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Evans OJ, Norman J, Carter LJ, Hutchinson T, Don A, Wright RM, Tuhtan JA, Toming G, Bolland JD. Rethinking fish-friendliness of pumps by shifting focus to both safe and timely fish passage for effective conservation. Sci Rep 2024; 14:17888. [PMID: 39095511 PMCID: PMC11297292 DOI: 10.1038/s41598-024-67870-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024] Open
Abstract
Globally, catadromous freshwater eels of the genus Anguilla are of conservation concern, including critically endangered European eel (Anguilla anguilla). Pumping stations that move river water to a higher elevation severely impact eels during their seaward spawning migration. Fish-friendly pumps can mitigate fish injury and mortality but here we uniquely rethink a fish-friendly pump as a fish passage solution. In this pluriannual study, the seasonal timing of pump operation was misaligned with the typical silver eel migration period. Eels were almost exclusively nocturnal but night-time pumping represented as little as 5.6% a year. Night-time eel approaches were primarily influenced by pump duration and temperature, but did not align with lunar phase, unlike in unregulated rivers. After reaching the pumping station, eel passage was influenced by weedscreen aperture and increased when the aperture was increased. Passive sensor collision suggested non-pump infrastructure could cause injury and mortality to eels. It is therefore recommended pump operation should align with the timing of silver eel migration, weedscreen and pump entrance efficiencies should be maximised, and non-pump infrastructure must have low fish injury risk. Ultimately, considering the entire structure a fish passage solution will help ensure fish-friendly pumps have high conservation value for anguillid eels globally.
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Affiliation(s)
- Oliver J Evans
- Hull International Fisheries Institute, University of Hull, Hull, UK
- Energy and Environment Institute, University of Hull, Hull, HU6 7RX, UK
| | - Josh Norman
- Hull International Fisheries Institute, University of Hull, Hull, UK
| | - Liam J Carter
- Hull International Fisheries Institute, University of Hull, Hull, UK
| | - Thomas Hutchinson
- Hull International Fisheries Institute, University of Hull, Hull, UK
| | - Andrew Don
- Environment Agency, Rivers House, East Quay, Bridgwater, Somerset, TA6 4YS, UK
| | - Rosalind M Wright
- Environment Agency, Inworth Road, Rivers House, Threshelfords Business Park, Feering, CO5 9SE, UK
| | - Jeffrey A Tuhtan
- Department of Computer Systems, Tallinn University of Technology, Ehitajate Tee 5, 19086, Tallinn, Estonia
| | - Gert Toming
- Department of Computer Systems, Tallinn University of Technology, Ehitajate Tee 5, 19086, Tallinn, Estonia
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Ono Y, Tsuchida S, Hirasaka K, Myosho T, Fujimoto S, Shimizu K, Yagi M. Environmental DNA Reveals Geographic Distributions of Two eel Species, Anguilla japonica and A. marmorata, in Western Kyushu, Japan. Zoolog Sci 2024; 41:392-399. [PMID: 39093285 DOI: 10.2108/zs230103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/22/2024] [Indexed: 08/04/2024]
Abstract
Some anguillid eels migrate thousands of kilometers from their spawning grounds, dispersing across vast geographic areas to fresh and brackish water habitats, where they settle and grow. Japanese eels (Anguilla japonica) and giant mottled eels (A. marmorata) are both found in Japan, although their distributions differ, and their exact distributions are poorly known. We assumed that topographic distribution patterns of Japanese and giant mottled eels must differ among and within rivers along the northwest coast of Kyushu, Japan. Environmental DNA (eDNA) analysis was conducted at 87 sites in 23 rivers. Japanese eel eDNA was detected in 19 rivers (82.6%) and that of giant mottled eels was detected in eight (34.8%). We detected giant mottled eel eDNA in five rivers where they were previously unknown. eDNA for Japanese eels was detected at six of nine sites in the north (66.7%), 13 of 23 sites in Omura (56.5%), and 37 of 55 sites in the south (67.3%). In contrast, giant mottled eel eDNA was detected at one of nine sites in the north (11.1%), no sites in Omura, and 15 of 55 sites in the south (27.3%). There was no correlation between eDNA concentrations of the two species at 10 sites in the five rivers where eDNA of both species was detected. These findings suggest differences in the distribution of the two eel species and the northern distributional limit of giant mottled eels in the area facing the East China Sea.
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Affiliation(s)
- Yurika Ono
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Shimpei Tsuchida
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Katsuya Hirasaka
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Taijun Myosho
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Shingo Fujimoto
- Integrated Technology Center, University of the Ryukyus, Okinawa 903-0213, Japan
| | - Kenichi Shimizu
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Mitsuharu Yagi
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan,
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3
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Koster W, Church B, Crook D, Dawson D, Fanson B, O'Connor J, Stuart I. Factors influencing migration of short-finned eels (Anguilla australis) over 3 years from a wetland system, Lake Condah, south-east Australia, downstream to the sea. JOURNAL OF FISH BIOLOGY 2024; 104:1824-1835. [PMID: 38483100 DOI: 10.1111/jfb.15726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/07/2024] [Accepted: 02/27/2024] [Indexed: 06/27/2024]
Abstract
Anguillid eel populations are under threat globally. A particularly vulnerable life-cycle stage is the migration of mature adult eels downstream from freshwater habitats through estuaries into the sea to spawn. This study investigated the factors associated with downstream migration of the short-finned eel Anguilla australis (Richardson 1841) from a coastal wetland (Lake Condah) in south-east Australia, using acoustic telemetry. Migration was associated with time of the year, higher water level and river flows, decreasing water temperature, and darker moon phases. Larger individuals and those in better condition were more likely to migrate from the wetland. Downstream migration peaked in spring, in contrast to the typical autumn migration period for other temperate anguillids. Variable responses, in comparison to other studies, highlight how migration cues may not be universal. In south-east Australia, short-finned eels may have evolved to migrate in multiple phases by first migrating to the estuary during typical seasonal spring flow pulses (e.g., to avoid being stranded in upland reaches during dry summer periods) and then migrating into the ocean in autumn. More research is needed to unravel these processes and causes, especially considering that the relationship between migration and hydrology may be complex and confounded (e.g., by human-induced disruptions to migratory pathways).
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Affiliation(s)
- Wayne Koster
- Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
| | - Ben Church
- Winda-Mara Aboriginal Corporation, Heywood, Victoria, Australia
| | - David Crook
- NSW Department of Primary Industries, Narrandera, New South Wales, Australia
| | - David Dawson
- Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
| | - Ben Fanson
- Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
| | - Justin O'Connor
- Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
| | - Ivor Stuart
- Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
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4
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Shuai F, Li H, Li J, Jiang T, Yang J, Yang W. Unravelling the life-history patterns and habitat preferences of the Japanese eel (Anguilla japonica) in the Pearl River, China. JOURNAL OF FISH BIOLOGY 2024; 104:387-398. [PMID: 36600527 DOI: 10.1111/jfb.15303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Eels have fascinated biologists for centuries due to their amazing long-distance migrations between freshwater habitats and very distant ocean spawning areas. The migratory life histories of the Japanese eel, Anguilla japonica, in the waters of south China are not very clear despite its ecological importance, and the need for fishery regulation and management. In this study, strontium (Sr) and calcium (Ca) microchemical profiles of the otoliths of silver eels were measured by X-ray electron probe microanalysis based on data collected from different habitats (including freshwater and brackish habitats), in the large subtropical Pearl River. The corresponding habitat preference characteristics were further analysed using redundancy analysis (RDA). A total of 195 Japanese eels were collected over 6 years. The collected individuals ranged from 180 to 771 mm in total length and from 8 to 612 g in body weight. Two-dimensional pictures of the Sr:Ca concentrations in otoliths revealed that the A. japonica in the Pearl River are almost entirely river eels, spending the majority of their lives in fresh water without exposure to salt water, while the catadromous migration time has delayed about 1 month in the Pearl River estuary in the past 20 years. RDA analysis further indicated that juveniles and adults preferred water with high salinity and high tide levels. Youth preferred habitats with high river fractals. Our findings contribute to a growing body of evidence showing that the eels are extremely scarce currently and conservation measures against them are imminent, including the protection of brackish and freshwater areas where they live in south China.
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Affiliation(s)
- Fangmin Shuai
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Haiyan Li
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Jie Li
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Tao Jiang
- Key Laboratory of Ecological Environment and Resources of Inland Fisheries, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Jian Yang
- Key Laboratory of Ecological Environment and Resources of Inland Fisheries, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Wanling Yang
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
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Ulmo‐Diaz G, Engman A, McLarney WO, Lasso Alcalá CA, Hendrickson D, Bezault E, Feunteun E, Prats‐Léon FL, Wiener J, Maxwell R, Mohammed RS, Kwak TJ, Benchetrit J, Bougas B, Babin C, Normandeau E, Djambazian HHV, Chen S, Reiling SJ, Ragoussis J, Bernatchez L. Panmixia in the American eel extends to its tropical range of distribution: Biological implications and policymaking challenges. Evol Appl 2023; 16:1872-1888. [PMID: 38143897 PMCID: PMC10739100 DOI: 10.1111/eva.13599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/25/2023] [Accepted: 09/06/2023] [Indexed: 12/26/2023] Open
Abstract
The American eel (Anguilla rostrata) has long been regarded as a panmictic fish and has been confirmed as such in the northern part of its range. In this paper, we tested for the first time whether panmixia extends to the tropical range of the species. To do so, we first assembled a reference genome (975 Mbp, 19 chromosomes) combining long (PacBio and Nanopore and short (Illumina paired-end) reads technologies to support both this study and future research. To test for population structure, we estimated genotype likelihoods from low-coverage whole-genome sequencing of 460 American eels, collected at 21 sampling sites (in seven geographic regions) ranging from Canada to Trinidad and Tobago. We estimated genetic distance between regions, performed ADMIXTURE-like clustering analysis and multivariate analysis, and found no evidence of population structure, thus confirming that panmixia extends to the tropical range of the species. In addition, two genomic regions with putative inversions were observed, both geographically widespread and present at similar frequencies in all regions. We discuss the implications of lack of genetic population structure for the species. Our results are key for the future genomic research in the American eel and the implementation of conservation measures throughout its geographic range. Additionally, our results can be applied to fisheries management and aquaculture of the species.
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Affiliation(s)
- Gabriela Ulmo‐Diaz
- Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
| | - Augustin Engman
- University of Tennessee Institute of Agriculture, School of Natural ResourcesKnoxvilleTennesseeUSA
| | | | | | - Dean Hendrickson
- Department of Integrative Biology and Biodiversity CollectionsUniversity of Texas at AustinAustinTexasUSA
| | - Etienne Bezault
- UMR 8067 BOREA, Biologie Organismes Écosystèmes Aquatiques (MNHN, CNRS, SU, IRD, UCN, UA)Université des AntillesPointe‐à‐PitreGuadeloupe
- Caribaea Initiative, Département de BiologieUniversité Des Antilles‐Campus de FouillolePointe‐à‐PitreGuadeloupeFrance
| | - Eric Feunteun
- UMR 7208 BOREABiologie Organismes Écosystèmes Aquatiques (MNHN, CNRS, SU,IRD, UCN, UA)Station Marine de DinardRennesFrance
- EPHE‐PSLCGEL (Centre de Géoécologie Littorale)DinardFrance
| | | | - Jean Wiener
- Fondation pour la Protection de la Biodiversité Marine (FoProBiM)CaracolHaiti
| | - Robert Maxwell
- Inland Fisheries SectionLouisiana Department of Wildlife and FisheriesLouisianaUSA
| | - Ryan S. Mohammed
- The University of the West Indies (UWI)St. AugustineTrinidad and Tobago
- Present address:
Department of Biological SciencesAuburn UniversityAuburnAlabamaUSA
| | - Thomas J. Kwak
- US Geological SurveyNorth Carolina Cooperative Fish and Wildlife Research UnitDepartment of Applied EcologyNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | | | - Bérénice Bougas
- Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
| | - Charles Babin
- Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
| | - Eric Normandeau
- Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
| | - Haig H. V. Djambazian
- McGIll Genome Centre, Department of Human GeneticsVictor Phillip Dahdaleh Institute of Genomic MedicineMcGill UniversityMontrealQuebecCanada
| | - Shu‐Huang Chen
- McGIll Genome Centre, Department of Human GeneticsVictor Phillip Dahdaleh Institute of Genomic MedicineMcGill UniversityMontrealQuebecCanada
| | - Sarah J. Reiling
- McGIll Genome Centre, Department of Human GeneticsVictor Phillip Dahdaleh Institute of Genomic MedicineMcGill UniversityMontrealQuebecCanada
| | - Jiannis Ragoussis
- McGIll Genome Centre, Department of Human GeneticsVictor Phillip Dahdaleh Institute of Genomic MedicineMcGill UniversityMontrealQuebecCanada
| | - Louis Bernatchez
- Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
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6
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Jacoby DMP, Piper AT. What acoustic telemetry can and cannot tell us about fish biology. JOURNAL OF FISH BIOLOGY 2023. [PMID: 37837176 DOI: 10.1111/jfb.15588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/29/2023] [Accepted: 10/11/2023] [Indexed: 10/15/2023]
Abstract
Acoustic telemetry (AT) has become ubiquitous in aquatic monitoring and fish biology, conservation, and management. Since the early use of active ultrasonic tracking that required researchers to follow at a distance their species of interest, the field has diversified considerably, with exciting advances in both hydrophone and transmitter technology. Once a highly specialized methodology, however, AT is fast becoming a generalist tool for those wishing to study or conserve fishes, leading to diversifying application by non-specialists. With this transition in mind, we evaluate exactly what AT has become useful for, discussing how the technological and analytical advances around AT can address important questions within fish biology. In doing so, we highlight the key ecological and applied research areas where AT continues to reveal crucial new insights and, in particular, when combined with complimentary research approaches. We provide a comprehensive breakdown of the state of the art for applications of AT, discussing the ongoing challenges, where its strengths lie, and how future developments may revolutionize fisheries management, behavioral ecology and species protection. Through selected papers we illustrate specific applications across the broad spectrum of fish biology. By bringing together the recent and future developments in this field under categories designed to broadly capture many aspects of fish biology, we hope to offer a useful guide for the non-specialist practitioner as they attempt to navigate the dizzying array of considerations and ongoing developments within this diverse toolkit.
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Affiliation(s)
- David M P Jacoby
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
- Institute of Zoology, Zoological Society of London, London, UK
| | - Adam T Piper
- Institute of Zoology, Zoological Society of London, London, UK
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7
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Vidal A, Phuong NN, Métais I, Gasperi J, Châtel A. Assessment of microplastic contamination in the Loire River (France) throughout analysis of different biotic and abiotic freshwater matrices. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 334:122167. [PMID: 37437763 DOI: 10.1016/j.envpol.2023.122167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/06/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
The contamination of microplastics (MP) in freshwater environments represent a major way for the MP transport in the environment. The assessment of MP pollution in freshwater compartments is then important to visualize the pressure and the impacts on medium, and to set up necessary measures. In this context, this study focused on the influence of anthropogenic activities of a medium French city (Angers) on MP levels in samples collected from the Loire River, the longest river in France. Abiotic and biotic matrices were collected upstream and downstream Angers. A first analysis was performed based on microscopy to determine the size, colour and shape of suspected MP and a complementary analysis by μ-FTIR (micro-Fourier Transform InfraRed) was conducted to determine the composition of plastic particles. Three organisms belonging to different trophic levels were studied: when the MP level was expressed per individual, the lowest abundance of MP was found in Tubifex sp. Followed by Corbicula fluminea, while the highest was measured in Anguilla anguilla. To establish the relationship with their habitat, the presence of MP in sediment and water was also analysed. Therefore, this works constitutes a complete overview of the MP levels in freshwater abiotic and biotic matrices. Overall, the presence of MP in analysed samples did not follow a particular pattern, neither in the sites nor matrices: the characteristics depending on a multifactorial outcome (feeding mode, organism size …). However, correlation of MP pattern between clams and sediment was quite evident, while the one between worms and their habitat was not. This demonstrates the relevance of investigating plastic contamination both in biotic and abiotic matrices. Finally, a standardisation of sampling and analytical analysis protocols would be helpful to make comparisons between studies more robust.
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Affiliation(s)
- Alice Vidal
- Laboratoire BIOSSE, Université Catholique de L'Ouest (UCO), 3 Place André Leroy, 49100, Angers, France.
| | - Ngoc-Nam Phuong
- Laboratoire Eau et Environnement, Université Gustave Eiffel, Allée des Ponts et Chaussées, 44340, Bouguenais, France
| | - Isabelle Métais
- Laboratoire BIOSSE, Université Catholique de L'Ouest (UCO), 3 Place André Leroy, 49100, Angers, France
| | - Johnny Gasperi
- Laboratoire Eau et Environnement, Université Gustave Eiffel, Allée des Ponts et Chaussées, 44340, Bouguenais, France
| | - Amélie Châtel
- Laboratoire BIOSSE, Université Catholique de L'Ouest (UCO), 3 Place André Leroy, 49100, Angers, France
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Williamson MJ, Pike C, Gollock M, Jacoby DMP, Piper AT. Anguillid eels. Curr Biol 2023; 33:R888-R893. [PMID: 37699341 DOI: 10.1016/j.cub.2023.07.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Anguillid eels have fascinated humans for centuries, but our knowledge of these mysterious fish is still scant. There are 19 species or subspecies in the genus Anguilla, which are found globally, except in the eastern Pacific and southern Atlantic. Their common label 'freshwater eels' is a misnomer - all anguillids are facultatively catadromous, born in marine environments, developing in continental waters, with a proportion never entering freshwater at all. Anguillid eels have several life history traits that have allowed them to exploit a broad range of habitats. As such, anguillid eels play an important ecological role in both marine and freshwater environments as well as being commercially valuable. Because of this, anguillid eels are under threat from multiple stressors, such as barriers to migration, pollution, parasites, disease, climate change and unsustainable exploitation. Six species are listed as Threatened in the Red List of Threatened Species, and four are listed as Data Deficient. Strengthening conservation and management of these species is essential, and further research provides an exciting opportunity to develop a greater understanding of this mysterious clade of fish.
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Affiliation(s)
- Michael J Williamson
- Institute of Zoology, Zoological Society of London, Outer Circle, Regent's Park, London NW1 4RY, UK; Department of Genetics, Evolution and Environment, University College London, Darwin Building, 99-105 Gower Street, London WC1E 6BT, UK.
| | - Charlotte Pike
- Conservation and Policy, Zoological Society of London, Outer Circle, Regent's Park, London NW1 4RY, UK
| | - Matthew Gollock
- Conservation and Policy, Zoological Society of London, Outer Circle, Regent's Park, London NW1 4RY, UK
| | - David M P Jacoby
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Adam T Piper
- Institute of Zoology, Zoological Society of London, Outer Circle, Regent's Park, London NW1 4RY, UK; Department of Genetics, Evolution and Environment, University College London, Darwin Building, 99-105 Gower Street, London WC1E 6BT, UK
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Liang Y, Liu H, Zhai S, Huang L, Huang W, Huang B, Xu J, Xiong J, Wang B. Effects of weaning American glass eels ( Anguilla rostrata) with the formula diet on intestinal microbiota and inflammatory cytokines genes expression. Heliyon 2023; 9:e16965. [PMID: 37346341 PMCID: PMC10279831 DOI: 10.1016/j.heliyon.2023.e16965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 04/27/2023] [Accepted: 06/02/2023] [Indexed: 06/23/2023] Open
Abstract
This study aimed to investigate the effects of weaning American glass eels (Anguilla rostrata) with the formula diet on intestinal microbiota and the expression of inflammatory cytokines genes. During the feeding trial, the control group (termed IF group) was fed with initial feed for 34 days, and the experimental group (termed FF group) was fed with initial feed for 30 days, and then weaned with the formula diet for 4 days. After feeding trial, intestines were subjected to microbiota analysis using 16S rDNA high-throughput sequencing, and expression of three inflammatory cytokines genes in gut were examined by qPCR. The results indicated that the species richness and diversity of intestinal microbiota exhibited significantly higher in FF group than that in IF group (P < 0.05). At the phylum level, the core intestinal microflora was the same for two groups. The most abundant phylum was Firmicutes in IF group, while it was Proteobacteria in FF group. Five genera were significantly higher in the IF group compared with the FF group, and Bacillus was the most major enriched biomarker at genus level. Nine genera were significantly higher in the FF group compared with the IF group, and Acidovorax was the most major enriched biomarker. Weaning from initial feeding diet to formula feeding diet enhanced the expression levels of TNF-α and IL-8, and there was no significant change in IL-1β expression between the two groups. These findings would be very useful to improve the diet formulation for weaning stage of American glass eels.
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Affiliation(s)
- Ying Liang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Zhanjiang, Guangdong, 524088, China
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, PR China, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Haizi Liu
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Shaowei Zhai
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Wenshu Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Bei Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Jisong Xu
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Jing Xiong
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, PR China, Xiamen, Fujian, 361021, China
| | - Bei Wang
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Zhanjiang, Guangdong, 524088, China
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Goymer A, Steele K, Jenkins F, Burgess G, Andrews L, Baumgartner N, Gubili C, Griffiths AM. For R-eel?! Investigating international sales of critically endangered species in freshwater eel products with DNA barcoding. Food Control 2023. [DOI: 10.1016/j.foodcont.2023.109752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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11
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Walther EJ, Zimmerman MS, Falke JA, Westley PAH. Species distributions and the recognition of risk in restoration planning: A case study of salmonid fishes. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2701. [PMID: 35751517 DOI: 10.1002/eap.2701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 04/06/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
One of the risks faced by habitat restoration practitioners is whether habitats included in restoration planning will be used by the target species or, conversely, whether habitats excluded from restoration planning would have benefited the target species. With the goal of providing a quantitative decision-making approach that represented varying levels of risk tolerance, we used multiple probability decision thresholds (PDT) to predict the range of occurrence for three anadromous fishes (Oncorhynchus spp.) in a watershed in southwestern Washington, USA. For each species, we compared the predicted range of occurrence to the distribution used for restoration planning and quantified the amount of habitat blocked by anthropogenic barriers. Coho salmon (O. kisutch) had the broadest predicted range of occurrence (3061.6-6357.9 km; 0.75-0.25 PDT), followed by steelhead trout (O. mykiss; 1828.8-2836.8 km) and chum salmon (O. keta; 1373.9-1629.1 km). For each species, the predicted range of occurrence was similar or greater than the distribution used for restoration planning, suggesting that the current plan may exclude habitats that would benefit each species. Coho salmon had the greatest percentage of habitat blocked by anthropogenic barriers, followed by steelhead trout and chum salmon, respectively. Modeling species distributions at multiple risk-tolerance scenarios acknowledges uncertainty in restoration planning and allows practitioners to weigh the ecological benefits and budgetary constraints when considering locations for restoration. To effectively communicate restoration science to support practitioners in decision-making, we developed an R Shiny application online user interface available at: https://shiny.wdfw-fish.us/ChehalisRiverBasinSalmonidRangeOfOccurence/.
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Affiliation(s)
- Eric J Walther
- Fish Ecology and Life Cycle Monitoring Unit, Science Division, Fish Program, Washington Department of Fish and Wildlife, Olympia, Washington, USA
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Mara S Zimmerman
- Fish Ecology and Life Cycle Monitoring Unit, Science Division, Fish Program, Washington Department of Fish and Wildlife, Olympia, Washington, USA
| | - Jeffrey A Falke
- Alaska Cooperative Fish and Wildlife Research Unit, United States Geological Survey, Fairbanks, Alaska, USA
| | - Peter A H Westley
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA
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12
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Wakiya R, Itakura H, Hirae T, Igari T, Manabe M, Matsuya N, Miyata K, Sakata MK, Minamoto T, Yada T, Kaifu K. Slower growth of farmed eels stocked into rivers with higher wild eel density. JOURNAL OF FISH BIOLOGY 2022; 101:613-627. [PMID: 35678211 DOI: 10.1111/jfb.15131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Farmed anguillid eels are frequently stocked into natural fresh waters to enhance eel resources, but little is known about what happens to these eels or their interactions with wild eels after stocking. A recent study observed a depressed survival and growth rate of farmed Japanese eels when they were reared with wild eels, which indicated that wild eels might interfere with the survival and growth of farmed-and-stocked eels through intraspecific competition. To contribute to improving eel stocking efficiency, the growth of farmed-and-stocked Japanese eels was compared among four rivers with different wild eel densities using mark-and-recapture studies. Based on the 2-year recapture survey after stocking, it was found that the density of the farmed-and-stocked eels was not significantly different among rivers. The daily growth rates of farmed-and-stocked eels in the rivers with lower wild eel density were significantly higher than those of the eels stocked into the rivers with higher wild eel density. The farmed-and-stocked eels moved significantly greater distances downstream than wild eels that showed sedentary behaviour. This and previous studies indicate that significant questions remain about the effectiveness of stocking farmed eels into water bodies where naturally recruited wild eels are present.
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Affiliation(s)
- Ryoshiro Wakiya
- Research and Development Initiative, Chuo University, Tokyo, Japan
| | - Hikaru Itakura
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland, USA
| | - Tatsumu Hirae
- Fisheries Technology and Development Center, Kagoshima, Japan
| | - Tadamitsu Igari
- Fisheries Technology and Development Center, Kagoshima, Japan
| | - Miyuki Manabe
- Fisheries Technology and Development Center, Kagoshima, Japan
| | - Noriaki Matsuya
- Inland Water Fisheries Institute, Aomori Prefectural Industrial Technology Research Center, Aomori, Japan
| | | | - Masayuki K Sakata
- Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - Toshifumi Minamoto
- Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - Takashi Yada
- Nikko Field Station, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Nikko, Japan
| | - Kenzo Kaifu
- Faculty of Law, Chuo University, Hachioji-shi, Japan
- The Zoological Society of London, London, UK
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13
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Menéndez D, Álvarez A, Acle S, Peón P, Ardura A, Garcia-Vazquez E. Microplastics across biomes in diadromous species. Insights from the critically endangered Anguilla anguilla. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 305:119277. [PMID: 35427676 DOI: 10.1016/j.envpol.2022.119277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Microplastic pollution affects freshwater and marine biota worldwide, microplastics occurring even inside the organisms. With highly variable effects, from physical damage to toxicity of plastic compounds, microplastics are a potential threat to the biodiversity, community composition and organisms' health. This emerging pollutant could overstress diadromous species, which are exposed to both sea and river water in their life cycle. Here we have quantified microplastics in young European eel Anguilla anguilla, a critically endangered catadromous fish, entering three rivers in southwestern Bay of Biscay. River water, sediments and seawater were also analysed for microplastics. The microplastic type was identified using Fournier-Transform Infrared spectroscopy and then searched for their hazard potential at the European Chemical Agency site. Both riverine and sea microplastic pollution were predictors of eels' microplastic profile (types of microplastics by shape and colour): A. anguilla juveniles entering European rivers already carry some marine microplastics and acquire more from river water. Potentially hazardous plastic materials were found from eels, some of them dangerous for aquatic life following the European Chemical Agency. This confirms microplastics as a potential threat for the species. Between-rivers differences for microplastics profiles persistent over years highlight the convenience of analysing and preventing microplastics at a local spatial scale, to save diadromous species from this stressor. Since the origin of microplastics present in glass eels seems to be dual (continental + seawater), new policies should be promoted to limit the entry of microplastics in sea and river waters.
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Affiliation(s)
- Daniel Menéndez
- Department of Functional Biology, University of Oviedo, 33006, Oviedo, Spain
| | - Almudena Álvarez
- Centro de Experimentación Pesquera, Dirección General de Pesca Marítima, Consejería de Medio Rural y Cohesión Territorial Del Principado de Asturias, Centro Integrado de Formación Profesional Del Mar 2(a) Planta, Avda. Príncipe de Asturias 74, 33212, Gijón, Spain
| | - Susana Acle
- BIOPARC Acuario de Gijón S.A., Playa de Poniente, S/n, 33212, Gijón, Spain
| | - Paloma Peón
- Centro de Experimentación Pesquera, Dirección General de Pesca Marítima, Consejería de Medio Rural y Cohesión Territorial Del Principado de Asturias, Centro Integrado de Formación Profesional Del Mar 2(a) Planta, Avda. Príncipe de Asturias 74, 33212, Gijón, Spain
| | - Alba Ardura
- Department of Functional Biology, University of Oviedo, 33006, Oviedo, Spain
| | - Eva Garcia-Vazquez
- Department of Functional Biology, University of Oviedo, 33006, Oviedo, Spain.
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14
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Denis J, Rabhi K, Le Loc’h F, Ben Rais Lasram F, Boutin K, Kazour M, Diop M, Gruselle MC, Amara R. Role of estuarine habitats for the feeding ecology of the European eel (Anguilla anguilla L.). PLoS One 2022; 17:e0270348. [PMID: 35793283 PMCID: PMC9261484 DOI: 10.1371/journal.pone.0270348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/08/2022] [Indexed: 11/26/2022] Open
Abstract
This study aims to characterize and compare the feeding ecology of the European eels (Anguilla anguilla L.) during the continental phase (i.e. yellow and silver) along a salinity gradient (i.e. lower, middle and upper) in six northern France estuaries (i.e. brackish water). The diet and stable isotopic (i.e. δ15N and δ13C values) compositions of eels collected with a fyke net in six estuaries (Slack, Wimereux, Liane, Canche, Authie and Somme estuaries) located along the French coast of the eastern English Channel per season over a year were described by combining gut content and stable isotope analyses. Eel guts were dominated by typical BW prey, Malacostraca and Actinopterygii (54% and 40%, respectively), with the gammare Gammarus zaddachi and the green crab Carcinus maenas (38% and 14%, respectively), and smaller yellow eels of A. anguilla and juvenile European flounder, Platichthys flesus (19% and 14%, respectively) being the most frequently found in their guts. The δ13C values of a majority of eels confirmed the sea- and brackish water-specific carbon resources. Dietary and isotopic niche revealed no clear change between total length, silvering stages and seasons, but a significant difference between salinity gradients and estuaries. Eels δ13C values showed significant enrichment from upper to lower along the estuaries while the δ15N values showed an inverse effect, with the lowest values in the lower part and highest in the upper part. Higher variability in δ13C values in larger estuaries suggested that eels feed on a wide range of food sources than in smaller estuaries. While eels in the smaller estuaries fed mainly on Actinopterygii prey, eels in the larger ones had a lower trophic level (i.e. δ15N values) and fed mainly on Malacostraca prey. This spatial difference in dietary and isotopic niche is discussed in relation to biological structure of eel and environmental variables.
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Affiliation(s)
- Jérémy Denis
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | - Khalef Rabhi
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | | | - Frida Ben Rais Lasram
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | - Kévin Boutin
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | - Maria Kazour
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | - Mamadou Diop
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
| | - Marie-Christine Gruselle
- Parc Naturel Marin des Estuaires Picards et de la Mer d’Opale, OFB,
Saint-Étienne-au-Mont, France
| | - Rachid Amara
- Université Littoral Côte d’Opale, Université Lille, CNRS, IRD, UMR 8187,
LOG, Laboratoire d’Océanologie et de Géosciences, Wimereux,
France
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15
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Parchemin C, Tapissier-Bontemps N, Sasal P, Faliex E. Anguilla sp. diseases diagnoses and treatments: The ideal methods at the crossroads of conservation and aquaculture purposes. JOURNAL OF FISH DISEASES 2022; 45:943-969. [PMID: 35526273 DOI: 10.1111/jfd.13634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
Anguilla anguilla, A. japonica and A. rostrata are the most fished and consumed eel species. However, these species are Critically Endangered, Endangered and Endangered, respectively. A combination of factors is thought to be responsible for their decline including fisheries, climate change, habitat destruction, barriers to migration, pollution and pathogens. Among them, viruses, bacteria and parasites are causing weakening of wild eels and serious economic losses for fishermen and eel farmers. Early detection of pathogens is essential to provide appropriate responses both for conservation reasons and to limit economic losses. Classic diagnosis approaches are time consuming and invasive and usual treatments, for example, antipathogenic substances are becoming obsolete because of pathogen resistance and environmental impact problems. The need for early and non-invasive diagnostic methods as well as effective and environmentally friendly treatments has increased. Vaccine development and diet supplementation have known a growing interest since their use could allow prevention of diseases. In this review, we summarize the main pathogens-viruses, bacteria and parasites-of the three northern temperate eel species, the methods used to detect these pathogens and the different treatments used. We discussed and highlighted the need for non-invasive, rapid and efficient detection methods, as well as effective and environmentally friendly treatments for both conservation and aquaculture purposes.
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Affiliation(s)
- Christelle Parchemin
- Centre de Recherches Insulaires et Observatoire de l'Environnement (CRIOBE), Université de Perpignan, Perpignan Cedex, France
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), Université de Perpignan, Perpignan Cedex, France
| | - Nathalie Tapissier-Bontemps
- Centre de Recherches Insulaires et Observatoire de l'Environnement (CRIOBE), Université de Perpignan, Perpignan Cedex, France
| | - Pierre Sasal
- Centre de Recherches Insulaires et Observatoire de l'Environnement (CRIOBE), Université de Perpignan, Perpignan Cedex, France
| | - Elisabeth Faliex
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), Université de Perpignan, Perpignan Cedex, France
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16
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Regional Population Structure of the European Eel at the Southern Limit of Its Distribution Revealed by Otolith Shape Signature. FISHES 2022. [DOI: 10.3390/fishes7030135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Given the European eel population’s marked decrease since the 1980s, it has become urgent to collect information describing its regional population structure to improve management plans. The Minho River (NW-Portugal, SW-Europe) is an important basin for the eel at the southern limit of its distribution, but the species is poorly described. Thus, we aimed to study the structure of the European eel population in the Minho River using otolith shape analysis, which has proven to be effective in discriminating fish groups experiencing different environmental conditions through ontogeny. Our results showed complete discrimination between the two main types of habitats studied (tributaries and estuaries). Otoliths of eels from the estuary were rectangular and elliptic, whereas in the tributaries they presented a more round and circular form. Eels collected in both habitats were mostly yellow-stage eels with a similar age range, but the eels from the tributaries showed smaller length-at-age and lower body condition than those collected in the estuary. Additionally, the sex ratio was skewed towards males in the tributaries and females in the estuary. This study reveals that there are at least two distinct groups of eels in this basin, likely with different development characteristics.
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Abstract
Despite our critical dependence on aquatic wildlife, we lack a complete understanding of the drivers of population stability and structure for most fish species. Social network analysis has been increasingly used to investigate animal societies as it explicitly links individual decision-making to population-level processes and demography. While the study of social structure is of great ecological interest, it is also potentially important for species of economic value or of conservation concern. To date however, there has been little focus on how social processes are likely to influence the conservation of fish populations. Here we identify applications for how a social network approach can help address broad fish conservation themes such as population structure, biological invasions or fisheries management. We discuss the burgeoning opportunities offered and challenges still faced by current technologies to integrate social network approaches within fish conservation.
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18
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North Equatorial Current and Kuroshio velocity variations affect body length and distribution of the Japanese eel Anguilla japonica in Taiwan and Japan. Sci Rep 2022; 12:2888. [PMID: 35190605 PMCID: PMC8861004 DOI: 10.1038/s41598-022-06669-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 02/01/2022] [Indexed: 11/23/2022] Open
Abstract
The larval stage of Japanese eel travels a substantial distance over a long duration through the North Equatorial Current (NEC) and the Kuroshio, and the spawning behavior of mature eels leads to monthly arrival waves in eastern Taiwan between November and February. The total length (TL) of the glass eel relates to its larval duration and age; therefore, the TL can indicate the larval duration. The monthly mean TLs of eels along eastern Taiwan from 2010 to 2021 were used to estimate the batch age, and the recruitment patterns and relative abundances were compared. The TLs of glass eels followed a normal distribution, and the estimated ages were highly correlated with their mean TLs. Early recruit TLs were significantly greater than those of late recruits. The mean tracer drift time was longer in early recruitment months (November–December) than in later dates (February–March). The recruitment lag between Taiwan and Japan was approximately 1–1.5 months, with relative more abundance in Taiwan for the early recruits and in Japan for the late recruits. Speculated cohorts followed the main streams of the NEC and Kuroshio, and the monthly velocity changes of these currents could affect the mean TLs as well as the distribution patterns of Japanese glass eels in Taiwan and Japan.
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19
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Current Dependent Dispersal Characteristics of Japanese Glass Eel around Taiwan. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10010098] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Japanese eel larvae are passively transported to the East Asian Continental Shelf by the North Equatorial Current, Kuroshio and Kuroshio intrusion currents, and coastal currents. Previous studies have investigated the dispersal characteristics and pathways of Japanese glass eels. However, there are still limitations in these studies. According to long-term (2010–2020) catch data from the Fisheries Agency in Taiwan, the distribution and time series of glass eels recruitment to Taiwan are closely related to the surrounding ocean currents. Recruitment begins in eastern Taiwan via the mainstream Kuroshio and in southern Taiwan via the Taiwan Strait Warm Current. In central Taiwan, recruitment occurs from southern Taiwan, as well as from mainland China via the southern branch of the China Coast Current (CCC). The latest recruitment occurred in northern Taiwan and mainly comprised glass eels from mainland China via the northern branch of the CCC. A stronger monsoon during the La Niña phase could affect the recruitment time series in northern and eastern Taiwan. This study suggests that the recruitment directionality of glass eels is an indicator of the flow field of ocean/coastal currents and elucidates the dispersal characteristics of glass eels in the waters around Taiwan.
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20
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Verhelst P, Reubens J, Coeck J, Moens T, Simon J, Van Wichelen J, Westerberg H, Wysujack K, Righton D. Mapping silver eel migration routes in the North Sea. Sci Rep 2022; 12:318. [PMID: 35013394 PMCID: PMC8748739 DOI: 10.1038/s41598-021-04052-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/13/2021] [Indexed: 11/09/2022] Open
Abstract
Recent developments in tracking technology resulted in the mapping of various marine spawning migration routes of the European eel (Anguilla anguilla). However, migration routes in the North Sea have rarely been studied, despite many large European rivers and hence potential eel growing habitat discharge into the North Sea. In this study, we present the most comprehensive map to date with migration routes by silver European eels in the North Sea and document for the first time successful eel migration through the English Channel. Migration tracks were reconstructed for 42 eels tagged in Belgium and 12 in Germany. Additionally, some eels moved up north to exit the North Sea over the British Isles, confirming the existence of two different routes, even for eels exiting from a single river catchment. Furthermore, we observed a wide range in migration speeds (6.8–45.2 km day−1). We hypothesize that these are likely attributed to water currents, with eels migrating through the English Channel being significantly faster than eels migrating northward.
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Affiliation(s)
- Pieterjan Verhelst
- Marine Biology Research Group, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium. .,Research Institute for Nature and Forest (INBO), Aquatic Management, Havenlaan 88, bus 73, 1000, Brussels, Belgium.
| | - Jan Reubens
- Flanders Marine Institute (VLIZ), Wandelaarkaai 7, 8400, Ostend, Belgium
| | - Johan Coeck
- Research Institute for Nature and Forest (INBO), Aquatic Management, Havenlaan 88, bus 73, 1000, Brussels, Belgium
| | - Tom Moens
- Marine Biology Research Group, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium
| | - Janek Simon
- Institute of Inland Fisheries E.V. Potsdam Sacrow, Im Königswald 2, 14469, Potsdam, Germany
| | - Jeroen Van Wichelen
- Research Institute for Nature and Forest (INBO), Aquatic Management, Havenlaan 88, bus 73, 1000, Brussels, Belgium
| | - Håkan Westerberg
- Institute of Freshwater Research, Swedish University of Agricultural Sciences (SLU), 178 93, Drottningholm, Sweden
| | - Klaus Wysujack
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - David Righton
- Centre for Environment, Fisheries, and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT, UK
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21
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Koster WM, Aarestrup K, Birnie-Gauvin K, Church B, Dawson D, Lyon J, O’Connor J, Righton D, Rose D, Westerberg H, Stuart I. First tracking of the oceanic spawning migrations of Australasian short-finned eels (Anguilla australis). Sci Rep 2021; 11:22976. [PMID: 34836978 PMCID: PMC8626517 DOI: 10.1038/s41598-021-02325-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/15/2021] [Indexed: 12/05/2022] Open
Abstract
Anguillid eel populations have declined dramatically over the last 50 years in many regions of the world, and numerous species are now under threat. A critical life-history phase is migration from freshwater to distant oceans, culminating in a single life-time spawning event. For many anguillids, especially those in the southern hemisphere, mystery still shrouds their oceanic spawning migrations. We investigated the oceanic spawning migrations of the Australasian short-finned eel (Anguilla australis) using pop-up satellite archival tags. Eels were collected from river estuaries (38° S, 142° E) in south-eastern temperate Australia. In 2019, 16 eels were tracked for up to about 5 months, ~ 2620 km from release, and as far north as the tropical Coral Sea (22° S, 155° E) off the north-east coast of Australia. Eels from southern Australia appeared to access deep water off the Australian coast via two main routes: (i) directly east via Bass Strait, or (ii) south-east around Tasmania, which is the shortest route to deep water. Tagged eels exhibited strong diel vertical migrations, alternating between the warm euphotic zone (~ 100-300 m, 15-20 °C) at night and the mesopelagic zone (~ 700-900 m, 6-8 °C) during the day. Marine predators, probably lamnid sharks, tuna, or marine mammals, ended many eel migrations (at least ~ 30%), largely before the eels had left the Australian continental shelf. The long and risky marine migrations of Australasian eels highlight the need for better information on the processes contributing to eel mortality throughout the life cycle, including the impacts of future changes to oceanic currents, predator abundance and direct anthropogenic disturbances.
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Affiliation(s)
- Wayne M. Koster
- grid.508407.e0000 0004 7535 599XDepartment of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg, VIC 3084 Australia
| | - Kim Aarestrup
- grid.5170.30000 0001 2181 8870Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Kim Birnie-Gauvin
- grid.5170.30000 0001 2181 8870Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Ben Church
- Gunditj Mirring Traditional Owner Aboriginal Corporation, Edgar Street, Heywood, VIC 3304 Australia
| | - David Dawson
- grid.508407.e0000 0004 7535 599XDepartment of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg, VIC 3084 Australia
| | - Jarod Lyon
- grid.508407.e0000 0004 7535 599XDepartment of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg, VIC 3084 Australia
| | - Justin O’Connor
- grid.508407.e0000 0004 7535 599XDepartment of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg, VIC 3084 Australia
| | - David Righton
- grid.14332.370000 0001 0746 0155Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, NR330HT Suffolk UK ,grid.8273.e0000 0001 1092 7967School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ UK
| | - Denis Rose
- Gunditj Mirring Traditional Owner Aboriginal Corporation, Edgar Street, Heywood, VIC 3304 Australia
| | - Håkan Westerberg
- grid.6341.00000 0000 8578 2742Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences, Stångholmsvägen 2, 178 93 Drottningholm, Sweden
| | - Ivor Stuart
- grid.508407.e0000 0004 7535 599XDepartment of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg, VIC 3084 Australia
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22
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Yokouchi K, Itakura H, Wakiya R, Yoshinaga T, Mochioka N, Kimura S, Kaifu K. Cumulative effects of low‐height barriers on distributions of catadromous Japanese eels in Japan. Anim Conserv 2021. [DOI: 10.1111/acv.12725] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. Yokouchi
- National Research Institute of Fisheries Science Japan Fisheries Research and Education Agency Yokohama Japan
- Center for International Collaborative Research Nagasaki University Nagasaki Japan
| | - H. Itakura
- Chesapeake Biological Laboratory University of Maryland Center for Environmental Science Solomons MD USA
- Atmosphere and Ocean Research Institute The University of Tokyo Kashiwa Japan
| | - R. Wakiya
- Atmosphere and Ocean Research Institute The University of Tokyo Kashiwa Japan
- Research and Development Initiative Chuo University Hachioji Japan
| | - T. Yoshinaga
- School of Marine Biosciences Kitasato University Sagamihara Japan
| | - N. Mochioka
- Faculty of Agriculture Kyushu University Fukuoka Japan
| | - S. Kimura
- Atmosphere and Ocean Research Institute The University of Tokyo Kashiwa Japan
| | - K. Kaifu
- Faculty of Law Chuo University Hachioji Japan
- The Zoological Society of London London UK
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23
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Bracamonte SE, Knopf K, Monaghan MT. Encapsulation of Anguillicola crassus reduces the abundance of adult parasite stages in the European eel (Anguilla anguilla). JOURNAL OF FISH DISEASES 2021; 44:771-782. [PMID: 33270932 DOI: 10.1111/jfd.13301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/23/2020] [Accepted: 10/25/2020] [Indexed: 06/12/2023]
Abstract
Encapsulation of the parasitic nematode Anguillicola crassus Kuwahara, Niimi & Hagaki is commonly observed in its native host, the Japanese eel (Anguilla japonica Temminck & Schlegel). Encapsulation has also been described in a novel host, the European eel (A. anguilla L.), and there is evidence that encapsulation frequency has increased since the introduction of A. crassus. We examined whether encapsulation of A. crassus provides an advantage to its novel host in Lake Müggelsee, NE Germany. We provide the first evidence that encapsulation was associated with reduced abundance of adult A. crassus. This pattern was consistent in samples taken 3 months apart. There was no influence of infection on the expression of the two metabolic genes studied, but the number of capsules was negatively correlated with the expression of two mhc II genes of the adaptive immune response, suggesting a reduced activation. Interestingly, eels that encapsulated A. crassus had higher abundances of two native parasites compared with non-encapsulating eels. We propose that the response of A. anguilla to infection by A. crassus may interfere with its reaction to other co-occurring parasites.
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Affiliation(s)
- Seraina E Bracamonte
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Berlin Center for Genomics in Biodiversity Research, Berlin, Germany
- Faculty of Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
- Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Klaus Knopf
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Faculty of Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Michael T Monaghan
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Berlin Center for Genomics in Biodiversity Research, Berlin, Germany
- Institut für Biologie, Freie Universität Berlin, Berlin, Germany
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24
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Lagarde R, Courret D, Grondin H, Faivre L, Ponton D. Climbing for dummies: recommendation for multi‐specific fishways for the conservation of tropical eels and gobies. Anim Conserv 2021. [DOI: 10.1111/acv.12699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- R. Lagarde
- Université de Perpignan Via Domitia Centre de Formation et de Recherche sur les Environnements Méditerranéens UMR 5110 Perpignan France
- CNRS Centre de Formation et de Recherche sur les Environnements Méditerranéens UMR 5110 Perpignan France
| | - D. Courret
- OFB DRAS Pôle R&D Ecohydraulique OFB‐IMFT‐Pprime Allée du professeur Camille Soula Toulouse France
| | | | - L. Faivre
- OCEA Consult’ Ravine des Cabris France
| | - D. Ponton
- ENTROPIE IRD Université de La Réunion CNRS Université de la Nouvelle‐Calédonie Ifremer c/o Institut Halieutique et des Sciences Marines (IH.SM) Université de Toliara Toliara Madagascar
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25
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Movements of Non-Migrant European Eels in an Urbanised Channel Linking a Mediterranean Lagoon to the Sea. WATER 2021. [DOI: 10.3390/w13060839] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Transitional ecosystems and, particularly, Mediterranean lagoons represent important habitats for the European eel (Anguilla anguilla) population. In these habitats many anthropogenic pressures can disturb eel movements and, in turn, negatively affect the population. Despite the importance of movements during the non-migrant growing stage in eels, this topic is understudied in Mediterranean lagoons. We thus aim to describe the diel and seasonal phenology and the effect of environmental drivers on non-migrant eel movements. Videos obtained from an Adaptive Resolution Imaging Sonar (ARIS) acoustic camera that continuously recorded from October 2018 to April 2020 were processed to evaluate the daily number of eels swimming toward the lagoon. More than 60% of the 7207 eels observed were females with a size >45 cm. Movements were year-round and predominantly during the night. A Boosted Regression Tree analysis demonstrated that, among the 10 environmental drivers studied, flow velocity, water temperature, discharge of the main tributary, wind velocity and atmospheric pressure, had the strongest influence on eel movement activity. Non-migrant eel movements should be better incorporated into lagoon management plans through actions such as limiting dredging activities from 18:00 to midnight, especially when the water flows toward the lagoon and when the water temperature is higher than 12 °C.
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26
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Jousseaume T, Roussel JM, Beaulaton L, Bardonnet A, Faliex E, Amilhat E, Acou A, Feunteun E, Launey S. Molecular detection of the swim bladder parasite Anguillicola crassus (Nematoda) in fecal samples of the endangered European eel Anguilla anguilla. Parasitol Res 2021; 120:1897-1902. [PMID: 33674925 DOI: 10.1007/s00436-021-07100-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 02/22/2021] [Indexed: 11/29/2022]
Abstract
The European eel Anguilla anguilla is listed as critically endangered by the IUCN. Among many threats, the introduced parasitic nematode Anguillicola crassus is suspected to alter the eels' swim bladder and jeopardize their reproductive oceanic migration. To date, gaining knowledge about the distribution and prevalence of A. crassus requires individual sacrifice (over 50,000 eels were sacrificed for epidemiology studies since 2010). This paper describes a non-lethal molecular protocol for identifying prevalence of A. crassus in A. anguilla, based on searching for A. crassus DNA in the feces of eels. Tests using three DNA microsatellite markers specific to the nematode showed that molecular detection provided similar results to visual examination of the swim bladder in up to 80% of the cases, and allowed for comparison of prevalence among sites. Easy to implement, this non-lethal protocol for detecting A. crassus could be valuable for management plans of this endangered species.
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Affiliation(s)
- Thibaut Jousseaume
- ESE, Ecology and Ecosystems Health, Agrocampus Ouest, INRAE, Rennes, France.,Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France
| | - Jean-Marc Roussel
- ESE, Ecology and Ecosystems Health, Agrocampus Ouest, INRAE, Rennes, France.,Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France
| | - Laurent Beaulaton
- Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France.,OFB, Direction de la Recherche et de l'Appui Scientifique, Rennes, France
| | - Agnès Bardonnet
- Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France.,INRAE, Université de Pau et des Pays de l'Adour, E2S UPPA, Collège STE, Ecobiop, St-Pée-sur-Nivelle, France
| | - Elisabeth Faliex
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (Cefrem), UMR 5110 CNRS-Université de Perpignan, Perpignan, France
| | - Elsa Amilhat
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (Cefrem), UMR 5110 CNRS-Université de Perpignan, Perpignan, France
| | - Anthony Acou
- Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France.,MNHN-Station de Biologie Marine de Dinard, CRESCO, Dinard, France
| | - Eric Feunteun
- MNHN-Station de Biologie Marine de Dinard, CRESCO, Dinard, France.,Biologie des Organismes et Ecosystèmes Aquatiques, MNHN, CNRS, Sorbonne Université, IRD, Université Caen Normandie, Université des Antilles, Station Marine, Dinard, France
| | - Sophie Launey
- ESE, Ecology and Ecosystems Health, Agrocampus Ouest, INRAE, Rennes, France. .,Management of Diadromous Fish in their Environment, OFB, INRAE, Agrocampus Ouest, Univ Pau Pays Adour, 65 rue de Saint-Brieuc, 35042, Rennes, France.
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27
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Pratt TC, Stanley DR, Schlueter S, La Rose JK, Weinstock A, Jacobson PT. Towards a downstream passage solution for out-migrating American eel (Anguilla rostrata) on the St. Lawrence River. AQUACULTURE AND FISHERIES 2021. [DOI: 10.1016/j.aaf.2021.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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28
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Truter M, Hadfield KA, Weyl OLF, Smit NJ. Pseudodactylogyrus anguillae (Yin & Sproston, 1948) from the giant mottled eel Anguilla marmorata Quoy & Gaimard, 1824, in the Phongolo River, South Africa: an invader on the African continent. Parasitol Res 2021; 120:1247-1268. [PMID: 33544226 DOI: 10.1007/s00436-021-07071-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 01/25/2021] [Indexed: 10/22/2022]
Abstract
The global invasive anguillid gill parasite Pseudodactylogyrus anguillae (Yin and Sproston, 1948) has only recently been documented from eels in South Africa. As there is no known eel trade in South Africa, the source of introduction of this parasite has been debated, and its status as an alien parasite was rendered uncertain. We report on the first infection of Pseudodactylogyrus anguillae from the giant mottled eel Anguilla marmorata from the Phongolo River (South Africa) using classic morphological and molecular methodologies and clarify the introduction status category of this parasite as alien and invasive.
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Affiliation(s)
- Marliese Truter
- Water Research Group, Unit for Environmental Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa. .,DSI/NRF Research Chair in Inland Fisheries and Freshwater Ecology, South African Institute for Aquatic Biodiversity, Makhanda, 6139, South Africa.
| | - Kerry A Hadfield
- Water Research Group, Unit for Environmental Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Olaf L F Weyl
- DSI/NRF Research Chair in Inland Fisheries and Freshwater Ecology, South African Institute for Aquatic Biodiversity, Makhanda, 6139, South Africa
| | - Nico J Smit
- Water Research Group, Unit for Environmental Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
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29
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Zan ND, Taha H, Arai T. First record of cannibalism in the giant mottled eel Anguilla marmorata (Actinopterygii: Anguilliformes) as revealed by DNA barcoding. ZOOLOGIA 2021. [DOI: 10.1590/s1984-4689.v38.e21007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Bourillon B, Acou A, Trancart T, Belpaire C, Covaci A, Bustamante P, Faliex E, Amilhat E, Malarvannan G, Virag L, Aarestrup K, Bervoets L, Boisneau C, Boulenger C, Gargan P, Becerra-Jurado G, Lobón-Cerviá J, Maes GE, Pedersen MI, Poole R, Sjöberg N, Wickström H, Walker A, Righton D, Feunteun É. Assessment of the quality of European silver eels and tentative approach to trace the origin of contaminants - A European overview. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140675. [PMID: 32927526 DOI: 10.1016/j.scitotenv.2020.140675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
The European eel is critically endangered. Although the quality of silver eels is essential for their reproduction, little is known about the effects of multiple contaminants on the spawning migration and the European eel management plan does not take this into account. To address this knowledge gap, we sampled 482 silver eels from 12 catchments across Europe and developed methods to assess three aspects of eel quality: muscular lipid content (N = 169 eels), infection with Anguillicola crassus (N = 482), and contamination by persistent organic pollutants (POPs, N = 169) and trace elements (TEs, N = 75). We developed a standardized eel quality risks index (EQR) using these aspects for the subsample of 75 female eels. Among 169 eels, 33% seem to have enough muscular lipids content to reach the Sargasso Sea to reproduce. Among 482 silver eels, 93% were infected by A. crassus at least once during their lifetime. All contaminants were above the limit of quantification, except the 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), Ag and V. The contamination by POPs was heterogeneous between catchments while TEs were relatively homogeneous, suggesting a multi-scale adaptation of management plans. The EQR revealed that eels from Warwickshire were most impacted by brominated flame-retardants and agricultural contaminants, those from Scheldt were most impacted by agricultural and construction activities, PCBs, coal burning, and land use, while Frémur eels were best characterized by lower lipid contents and high parasitic and BTBPE levels. There was a positive correlation between EQR and a human footprint index highlighting the capacity of silver eels for biomonitoring human activities and the potential impact on the suitability of the aquatic environment for eel population health. EQR therefore represents a step forward in the standardization and mapping of eel quality risks, which will help identify priorities and strategies for restocking freshwater ecosystems.
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Affiliation(s)
- Bastien Bourillon
- Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS FRE 2030, Sorbonne Université, IRD 207, Université de Caen Normandie, Université des Antilles, Centre de Recherche et d'Enseignement sur les Systèmes Côtiers, station de biologie marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France.
| | - Anthony Acou
- UMS 2006 Patrimoine Naturel (PatriNat, OFB/CNRS/MNHN), Centre de Recherche et d'Enseignement sur les Systèmes Côtiers, station de biologie marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France; OFB, Management of Diadromous Fish in their Environment OFB-INRAE-Agrocampus Ouest-UPPA, 65 rue de Saint Brieuc, 35042 Rennes Cedex, France
| | - Thomas Trancart
- Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS FRE 2030, Sorbonne Université, IRD 207, Université de Caen Normandie, Université des Antilles, Centre de Recherche et d'Enseignement sur les Systèmes Côtiers, station de biologie marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France
| | - Claude Belpaire
- Institute for Nature and Forest Research (INBO), Dwersbos 28, 1630 Linkebeek, Belgium
| | - Adrian Covaci
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS - Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle, France; Institut Universitaire de France (IUF), 1 rue Descartes, 75005 Paris, France
| | - Elisabeth Faliex
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (Cefrem), UMR 5110 CNRS-Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, F-66860 Perpignan Cedex, France
| | - Elsa Amilhat
- Centre de Formation et de Recherche sur les Environnements Méditerranéens (Cefrem), UMR 5110 CNRS-Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, F-66860 Perpignan Cedex, France
| | - Govindan Malarvannan
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Laure Virag
- Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS FRE 2030, Sorbonne Université, IRD 207, Université de Caen Normandie, Université des Antilles, Centre de Recherche et d'Enseignement sur les Systèmes Côtiers, station de biologie marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France
| | - Kim Aarestrup
- DTU AQUA, National Institute of Aquatic Resources, Section for Freshwater Fisheries Ecology, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Lieven Bervoets
- University of Antwerp, Systemic Physiological and Ecotoxicological Research group (SPHERE), Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Catherine Boisneau
- UMR 7324 CItés, TERitoires, Environnement et Sociétés (CITERES, CNRS, Université de Tours), 33 Allée Ferdinand de Lesseps, 37200 Tours, France
| | - Clarisse Boulenger
- OFB, Management of Diadromous Fish in their Environment OFB-INRAE-Agrocampus Ouest-UPPA, 65 rue de Saint Brieuc, 35042 Rennes Cedex, France; INRAE, UMR 985, INRA-Agrocampus, Ecologie et Santé des Ecosystèmes, Rennes Cedex, France
| | - Paddy Gargan
- Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin 24, Ireland
| | - Gustavo Becerra-Jurado
- Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin 24, Ireland; Institute for European Environmental Policy, Department of Biodiversity and Ecosystem Services, Rue Joseph II 36-38, 1000 Brussels, Belgium
| | - Javier Lobón-Cerviá
- Department of evolutionary Ecology, National Museum of Natural Science (CSIC), C/. Jose Gutiérrez Abascal 2, Madrid 28006, Spain
| | - Gregory E Maes
- Aquaculture, Department of Biosystems, KU Leuven, 3001 Leuven, Belgium; Center for Human Genetics, UZ Leuven - Genomics Core, KU Leuven, Leuven 3000, Belgium; Centre for Sustainable Tropical Fisheries and Aquaculture, College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
| | - Michael Ingemann Pedersen
- DTU AQUA, National Institute of Aquatic Resources, Section for Freshwater Fisheries Ecology, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Russell Poole
- Marine Institute, Fisheries Ecosystems Advisory Services, Newport, Co. Mayo, Ireland
| | - Niklas Sjöberg
- Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Freshwater Research, Stångholmsvägen 2, SE-178 93 Drottningholm, Sweden
| | - Håkan Wickström
- Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Freshwater Research, Stångholmsvägen 2, SE-178 93 Drottningholm, Sweden
| | - Alan Walker
- Centre for Environment Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, England, United Kingdom
| | - David Righton
- Centre for Environment Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, England, United Kingdom
| | - Éric Feunteun
- Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS FRE 2030, Sorbonne Université, IRD 207, Université de Caen Normandie, Université des Antilles, Centre de Recherche et d'Enseignement sur les Systèmes Côtiers, station de biologie marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France
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31
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Itakura H, Wakiya R. Habitat preference, movements and growth of giant mottled eels, Anguilla marmorata, in a small subtropical Amami-Oshima Island river. PeerJ 2020; 8:e10187. [PMID: 33194404 PMCID: PMC7646302 DOI: 10.7717/peerj.10187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/24/2020] [Indexed: 02/02/2023] Open
Abstract
Although anguillid eel populations have decreased remarkably in recent decades, few detailed ecological studies have been conducted on tropical eels such as the giant mottled eel whose range extends across the whole Indo-Pacific. This species was studied throughout the entire 0.5 km mainstem reaches of Oganeku River on the subtropical Amami-Oshima Island of Japan over a two-year period using four sampling periods to understand its habitat preference, early life-stage dispersal process, movements, and annual growth using a mark-recapture experiment conducted with quantitative electrofishing. A total of 396 juvenile growth-phase A. marmorata eels were caught and tagged, with 48 individuals being recaptured at least once. Their density irrespective of size of eels was most strongly determined by distance from the river mouth, followed by riverbank type according to random forest models. Eel density decreased with increasing distance from the freshwater tidal limit located about 100-150 m from the river mouth. Eels preferred vegetated riverbanks, while they avoided those of concrete and sand. The density of small eels (total length: TL < 240 mm) was also associated with depth and velocity, with small eels tending to prefer riffle or run habitats. In contrast, large eels (TL ≥ 240 mm) were found in habitats of any depth and velocity. The TL of eels had a minimum peak at around the tidal limit, and it increased with increasing distance from the tidal limit. The observed density and size gradients of eels in relation to the distance from the river mouth suggested that A. marmorata initially recruited to freshwater tidal limit areas and then dispersed in both downstream and upstream directions. The growth rate of eels varied greatly among individuals that were at large for various periods of time and ranged from 0 to 163.2 mm/year (mean ± SD of 31.8 ± 31.0 mm/year). Of the recaptured eels, 52.1% were recaptured in a section that was different from the original capture section, and their mean ± SD distance travelled was 46.5 ± 72.5 m (median = 20 m). 47.9% of the eels were recaptured from the original section of capture (i.e., <10 m distances travelled), suggesting that they had strong fidelity to specific habitats with limited movements. The distance travelled of eels that had moved was greater for small eels (range = 10-380 m; mean ± SD = 84.4 ± 121.9 m) than large individuals (range = 10-120 m; mean ± SD = 30.9 ± 31.0 m), which indicates that the mobility of the eels declines as they grow. This is the first clear detailed documentation of the spatial distribution, growth, and movements of tropical eels in a small river system in relation to environmental conditions that provides an example of how future studies can be conducted in other areas to understand how conservation efforts can be most efficiently targeted for maximum success.
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Affiliation(s)
- Hikaru Itakura
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, United States of America
- Graduate School of Science, Kobe University, Kobe, Hyogo, Japan
| | - Ryoshiro Wakiya
- Research and Development Initiative, Chuo University, Bunkyo-ku, Tokyo, Japan
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba, Japan
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32
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Currie HAL, Flores Martin N, Espindola Garcia G, Davis FM, Kemp PS. A mechanical approach to understanding the impact of the nematode Anguillicoloides crassus on the European eel swimbladder. J Exp Biol 2020; 223:jeb219808. [PMID: 32748794 DOI: 10.1242/jeb.219808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/30/2020] [Indexed: 11/20/2022]
Abstract
One of the most detrimental factors in the drastic decline of the critically endangered European eel (Anguilla anguilla) was the inadvertent introduction of the invasive nematode Anguillicoloides crassus Infection primarily affects the swimbladder, a gas-filled organ that enables the eel to control its depth in the water. A reduction in swimbladder function may be fatal for eel undergoing their spawning migration to the Sargasso Sea, a journey of over 5000 km. Although the physiological damage caused by this invasive parasite is well studied through the use of quantifiable gross pathological indices, providing a good measure of the swimbladder health status, they cannot separate the role of mechanical and morphological damage. Our study examined the appropriateness of three commonly used indices as a measure of mechanical damage by performing uniaxial tensile tests on swimbladder specimens obtained from an infected eel population. When the test results were compared with the gross pathological indices it was found that thickness correlated most strongly with mechanical damage, both confirming and, more importantly, explaining the counterintuitive findings of earlier work. In a damaged swimbladder, the immune response leads to a trade-off; increasing wall thickness raises the pressure required for organ rupture but decreases strength. The results indicate that for moderate infection the mechanical integrity of the swimbladder can be maintained. For severe infection, however, a reduction in mechanical integrity may reach a tipping point, thereby affecting the successful completion of their oceanic migration.
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Affiliation(s)
- Helen A L Currie
- International Centre for Ecohydraulics Research, Faculty of Engineering and Physical Sciences, Boldrewood Innovation Campus, University of Southampton, Southampton SO16 7QF, UK
| | - Nicholas Flores Martin
- International Centre for Ecohydraulics Research, Faculty of Engineering and Physical Sciences, Boldrewood Innovation Campus, University of Southampton, Southampton SO16 7QF, UK
| | - Gerardo Espindola Garcia
- International Centre for Ecohydraulics Research, Faculty of Engineering and Physical Sciences, Boldrewood Innovation Campus, University of Southampton, Southampton SO16 7QF, UK
| | - Frances M Davis
- International Centre for Ecohydraulics Research, Faculty of Engineering and Physical Sciences, Boldrewood Innovation Campus, University of Southampton, Southampton SO16 7QF, UK
| | - Paul S Kemp
- International Centre for Ecohydraulics Research, Faculty of Engineering and Physical Sciences, Boldrewood Innovation Campus, University of Southampton, Southampton SO16 7QF, UK
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Capoccioni F, Leone C, Belpaire C, Malarvannan G, Poma G, De Matteis G, Tancioni L, Contò M, Failla S, Covaci A, Ciccotti E. Quality assessment of escaping silver eel (Anguilla anguilla L.) to support management and conservation strategies in Mediterranean coastal lagoons. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:570. [PMID: 32770417 DOI: 10.1007/s10661-020-08533-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Silver eel samples, collected from the lagoons of Fogliano and Caprolace (Italy), were investigated for a broad range of contaminants (29 polychlorinated biphenyls, 9 polybrominated diphenyl ethers, 5 dichlorodiphenyltrichloroethane, 5 chlordanes, hexachlorobenzene, 3 hexachlorocyclohexane, and 5 metals). Concentrations of targeted compounds stand for a general low contamination pattern. Infestation by Anguillicola crassus and virus infections were also examined. No parasite infestation was found, while infected silver eels had a low prevalence for EVEX, and, for the first time in the Mediterranean area, for AngHV-1. Overall, a good quality status of escaping silver eels, for both lagoons, was highlighted by the use of integrative Indexes. A quality assessment of the ecological status of the two lagoons was carried out developing an expert judgment approach, in order to characterize the habitat of eel stocks. A Final Pressure Index was derived, whose values showed an overall limited global anthropogenic impact acting on both lagoons. Results stand for the suitability of an integrated approach to assess lagoon habitats and eel local stocks quality. This could be proposed as a tool to identify sites yielding high quality eel spawners in the Mediterranean region, in order to set up suitable management frameworks, providing elements to appraise and discuss the potential of coastal lagoons in the Mediterranean region towards the recovery of the eel global stock.
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Affiliation(s)
- Fabrizio Capoccioni
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy.
| | - Chiara Leone
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
| | - Claude Belpaire
- Institute for Nature and Forest Research (INBO), Linkebeek, Belgium
| | | | - Giulia Poma
- Toxicological Centre, University of Antwerp, Wilrijk, Belgium
| | - Giovanna De Matteis
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Lorenzo Tancioni
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
| | - Michela Contò
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Sebastiana Failla
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Wilrijk, Belgium
| | - Eleonora Ciccotti
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
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Itakura H, Wakiya R, Gollock M, Kaifu K. Anguillid eels as a surrogate species for conservation of freshwater biodiversity in Japan. Sci Rep 2020; 10:8790. [PMID: 32472008 PMCID: PMC7260186 DOI: 10.1038/s41598-020-65883-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/06/2020] [Indexed: 11/17/2022] Open
Abstract
To monitor and manage biodiversity, surrogate species (i.e., indicator, umbrella and flagship species) have been proposed where conservation resources are focused on a limited number of focal organisms. Using data obtained from 78 sites across six rivers in the mainland Japan and the Amami-Oshima Island, we demonstrate that two anguillids – the Japanese eel (Anguilla japonica) and the giant mottled eel (A. marmorata) – can act as surrogate species for conservation of freshwater biodiversity. Anguillid eels were the widest topographically-distributed species ranging from near the mouth to the upper reaches of rivers. Moreover, stable isotopic analyses indicated that eels are likely one of the highest-order predators in freshwater ecosystems. A significant positive relationship was found between the density of eels and the number of other diadromous species collected. However, the optimal models revealed that both the density of eels and the number of other diadromous species were significantly negatively correlated with distance from the river mouth and cumulative height of trans-river structures from the river mouth to each site. This suggests the positive relationship between eel density and number of other diadromous species was indirect and related to river-ocean connectivity. Given their catadromous life-cycle, and global commercial and cultural importance, as a taxa, anguillid eels can act as indicator, umbrella and flagship species, and a comprehensive surrogate for conservation of freshwater biodiversity.
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Affiliation(s)
- Hikaru Itakura
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, 146 Williams St., Solomons, MD, 20688, USA. .,Graduate School of Science, Kobe University, 1-1 Rokkoudaichou, Nadaku, Kobe, Hyogo, 657-8501, Japan.
| | - Ryoshiro Wakiya
- Research and Development Initiative, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan.,Atmosphere and Ocean Research Institute, the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
| | - Matthew Gollock
- The Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Kenzo Kaifu
- Faculty of Law, Chuo University, 724-1 Higashinakano, Hachioji-shi, Tokyo, 192-0393, Japan
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35
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Frankowski J, Lübke K, Coke M, Weyl OLF. Genetic variability and demographic history of Anguilla mossambica (Peters, 1852) from continental Africa and Madagascar. JOURNAL OF FISH BIOLOGY 2020; 96:1251-1259. [PMID: 31777080 DOI: 10.1111/jfb.14220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
In this study, population genetic and demographic parameters were inferred using sequence data from 151 individuals of Anguilla mossambica originating from continental south and south-east Africa and Madagascar. The analyses were based on a 532 bp segment of the mitochondrial cytochrome b gene. The absence of genetic structuring was observed thereby supporting the hypothesis of panmixia for the endemic A. mossambica. The overall nucleotide diversity π = 0.002 and the haplotype diversity reached h = 0.691. Significant negative values from several tests of neutrality and mismatch analysis pointed to fluctuating historical population sizes. Bayesian averaging resulted in higher support for population growth models vs. a constant population-size model. Population decline and subsequent growth most likely predated the last glacial and were probably related to extended periods of extreme drought followed by wetter and more stable hydroclimate between 150 and 75,000 years before present (kBP). According to this scenario the female effective population size has increased since 110 kBP by c. two orders of magnitude to a recent level of about 650,000 (219,317-2,292,000).
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Affiliation(s)
- Jens Frankowski
- Institute of Fisheries, Mecklenburg-Vorpommern Research Centre for Agriculture and Fisheries, Gülzow, Germany
| | - Kay Lübke
- Department of Animal Physiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | | | - Olaf L F Weyl
- DST/NRF, South African Institute for Aquatic Biodiversity, Grahamstown/Makhanda, South Africa
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Barth JMI, Gubili C, Matschiner M, Tørresen OK, Watanabe S, Egger B, Han YS, Feunteun E, Sommaruga R, Jehle R, Schabetsberger R. Stable species boundaries despite ten million years of hybridization in tropical eels. Nat Commun 2020; 11:1433. [PMID: 32188850 PMCID: PMC7080837 DOI: 10.1038/s41467-020-15099-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 02/07/2020] [Indexed: 02/01/2023] Open
Abstract
Genomic evidence is increasingly underpinning that hybridization between taxa is commonplace, challenging our views on the mechanisms that maintain their boundaries. Here, we focus on seven catadromous eel species (genus Anguilla) and use genome-wide sequence data from more than 450 individuals sampled across the tropical Indo-Pacific, morphological information, and three newly assembled draft genomes to compare contemporary patterns of hybridization with signatures of past introgression across a time-calibrated phylogeny. We show that the seven species have remained distinct for up to 10 million years and find that the current frequencies of hybridization across species pairs contrast with genomic signatures of past introgression. Based on near-complete asymmetry in the directionality of hybridization and decreasing frequencies of later-generation hybrids, we suggest cytonuclear incompatibilities, hybrid breakdown, and purifying selection as mechanisms that can support species cohesion even when hybridization has been pervasive throughout the evolutionary history of clades.
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Affiliation(s)
- Julia M I Barth
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Chrysoula Gubili
- Fisheries Research Institute, Hellenic Agricultural Organisation-DEMETER, Nea Peramos, 64 007, Kavala, Greece
| | - Michael Matschiner
- Department of Palaeontology and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006, Zurich, Switzerland.
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway.
| | - Ole K Tørresen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Shun Watanabe
- Faculty of Agriculture, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Bernd Egger
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Yu-San Han
- Institute of Fisheries Science, College of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Eric Feunteun
- Laboratoire Biologie des Organismes et Écosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, Université de Caen Normandie, Université des Antilles, IRD, 61 Rue Buffon, CP 53, 75231, Paris Cedex 05, France
- MNHN-Station Marine de Dinard, Centre de Recherche et d'Enseignement Sur les Systèmes Côtiers (CRESCO), 38 Rue du Port Blanc, 35800, Dinard, France
| | - Ruben Sommaruga
- Department of Ecology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - Robert Jehle
- School of Science, Engineering and Environment, University of Salford, Salford Crescent, Salford, M5 4WT, UK.
| | - Robert Schabetsberger
- Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.
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Estimation of the spawning time of Japanese eels in the open ocean. Sci Rep 2020; 10:4172. [PMID: 32144285 PMCID: PMC7060335 DOI: 10.1038/s41598-020-61029-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/31/2020] [Indexed: 12/01/2022] Open
Abstract
To understand the spawning ecology of the Japanese eel, the spawning time of this species was estimated based on measurements of the ascending speed of eggs and previously obtained data. Two types of water temperature parameters were calculated assuming an arbitrary spawning time. The ‘incubation temperature’ of 53 eggs collected in the spawning area was estimated based on the developmental stage of each egg and experimentally determined relationships between water temperature and incubation duration. The ‘experienced temperature’ of eggs ascending in the water column after spawning was estimated based on an ascending egg speed of 3.69 m/h and spawning depth of 230 m determined from a pop-up satellite archival tag release experiment on silver eels conducted in the same area. The incubation and experienced temperatures of the eggs coincided only at 20:20–22:30 h, 3 days prior to the new moon. This period is only a few hours after the diel vertical migration of Japanese eels in the evening, when adults move up from a depth of ~800 m (approximately 5 °C) to shallower waters of 200–250 m depth (approximately 20 °C). Our findings will facilitate improvements in aquaculture techniques and the detection of eel spawning events in the open ocean.
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Hagihara S, Aoyama J, Sudo R, Limbong D, Ijiri S, Adachi S, Tsukamoto K. Reproductive physiological characteristics of tropical Celebes eels Anguilla celebesensis in relation to downstream migration and ovarian development. JOURNAL OF FISH BIOLOGY 2020; 96:558-569. [PMID: 31837014 DOI: 10.1111/jfb.14231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Downstream-migrating (n = 64) and non-migrating (n = 21) female Celebes eels Anguilla celebesensis were captured from the Poso Lake-River system on Sulawesi Island, Indonesia, and their reproductive physiological characteristics were examined. A histological observation of the ovaries revealed that most non-migrating eels were at the perinucleolus (43%) or oil-droplet (48%) stage, whereas most migrating eels were at the early vitellogenic (36%) or midvitellogenic (61%) stage. Transcript levels of gonadotropin genes (fshb, lhb) in the pituitary gland and concentrations of sex steroids [11-ketotestosterone (11-KT), testosterone, 17β-oestradiol (E2 )] in blood plasma of migrating eels were significantly higher than those of non-migrating eels. The fshb messenger (m)RNA levels were lower in perinucleolus and oil-droplet stages and then significantly increased in the early vitellogenic stage. The lhb mRNA levels in vitellogenic-stage eels were significantly higher than those in perinucleolus- and oil-droplet-stage eels. The 11-KT levels of eels at the oil-droplet and vitellogenic stages were significantly higher than those of eels at the perinucleolus stage. The E2 levels at the vitellogenic stage were significantly higher than those at the perinucleolus and oil-droplet stages. These dynamics of the reproductive hormones represented the physiological background of oogenesis in A. celebesensis that has remarkably well-developed oocytes just before downstream migration.
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Affiliation(s)
- Seishi Hagihara
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Jun Aoyama
- International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Iwate, Japan
| | - Ryusuke Sudo
- Minami-izu Laboratory, National Research Institute of Aquaculture, Japan Fisheries Research and Education Agency, Shizuoka, Japan
| | | | - Shigeho Ijiri
- Graduate School of Fisheries Sciences, Hokkaido University, Hokkaido, Japan
| | - Shinji Adachi
- Graduate School of Fisheries Sciences, Hokkaido University, Hokkaido, Japan
| | - Katsumi Tsukamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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Richards JL, Sheng V, Yi CW, Ying CL, Ting NS, Sadovy Y, Baker D. Prevalence of critically endangered European eel ( Anguilla anguilla) in Hong Kong supermarkets. SCIENCE ADVANCES 2020; 6:eaay0317. [PMID: 32181342 PMCID: PMC7056311 DOI: 10.1126/sciadv.aay0317] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/11/2019] [Indexed: 05/27/2023]
Abstract
European eel (Anguilla anguilla) is a critically endangered species requiring CITES permits for international trade. Despite the fact that no imports to Hong Kong were declared within the last 2 years, our study found that this species is still commonly sold in major supermarket chains across Hong Kong. In a COI barcoding survey of 49 retail vendors encompassing 13 brands, 9 of 13 carried A. anguilla, and 45% of all eel products available at retail outlets (n = 49) were unambiguously identified as A. anguilla. Considering the visual similarity of eel species and disproportionate amount of undeclared A. anguilla available for consumption, this finding raises urgent concerns regarding the enforcement of international CITES trade regulations. Furthermore, the prevalence of A. anguilla in supermarkets highlights how illicit wildlife products are not solely limited to specialized affluent buyers; some species have entered mainstream distribution networks for the average consumer.
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Affiliation(s)
- John L. Richards
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - Victoria Sheng
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - Chung Wing Yi
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Chan Lai Ying
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Ng Sin Ting
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Yvonne Sadovy
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - David Baker
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
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40
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Hanzen C, Lucas MC, OʼBrien G, Calverley P, Downs CT. Surgical implantation of radio tags in three eel species (Anguilla spp.) in South Africa. JOURNAL OF FISH BIOLOGY 2020; 96:847-852. [PMID: 32003468 DOI: 10.1111/jfb.14270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
Studies have reported poor survival of surgically tagged freshwater fishes in warm African waters. This study aimed to assess the applicability of using radio telemetry (and surgical implantation of tags) for Anguilla spp. Nineteen yellow eels (Anguilla bengalensis, A. marmorata and A. mossambica) were surgically implanted with radio tags between October 2018 and January 2019 in the Thukela River, South Africa. Most eels were alive 6 months after tagging, and recaptured eels displayed advanced or complete healing at the incision site. Therefore, this method appears suitable for African freshwater eels.
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Affiliation(s)
- Céline Hanzen
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Martyn C Lucas
- University of Durham, Department of Biosciences, Durham, UK
| | - Gordon OʼBrien
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
- University of Mpumalanga, School of Biology and Environmental Sciences, Nelspruit, South Africa
| | - Peter Calverley
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Colleen T Downs
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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Kuroki M, Miller MJ, Feunteun E, Sasal P, Pikering T, Han YS, Faliex E, Acou A, Dessier A, Schabetsberger R, Watanabe S, Kawakami T, Onda H, Higuchi T, Takeuchi A, Shimizu M, Hewavitharane CA, Hagihara S, Taka T, Kimura S, Mochioka N, Otake T, Tsukamoto K. Distribution of anguillid leptocephali and possible spawning areas in the South Pacific Ocean. PROGRESS IN OCEANOGRAPHY 2020; 180:102234. [PMID: 33184522 PMCID: PMC7116347 DOI: 10.1016/j.pocean.2019.102234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Seven South Pacific anguillid eel species live from New Guinea to French Polynesia, but their spawning areas and life histories are mostly unknown despite previous sampling surveys. A July-October 2016 research cruise was conducted to study the spawning areas and times, and larval distributions of South Pacific anguillid eels, which included a short 155°E station-line northeast of New Guinea and five long transects (5-25°S, 160°E-140°W) crossing the South Equatorial (SEC) and other currents. This survey collected nearly 4000 anguilliform leptocephali at 179 stations using an Isaacs-Kidd Midwater Trawl accompanied by 104 CTD casts. Based on mor-phometric observations and DNA sequencing, 74 anguillid leptocephali were collected, which in the southern areas included 29 larvae of six species: Anguilla bicolor pacifica, A. marmorata, A. australis, A. reinhardtii, A. megastoma, and A. obscura (all anguillid species of the region were caught except A. dieffenbachii). Small A. australis (9.0-16.8 mm) and A. reinhardtii (12.4, 12.5 mm) leptocephali were collected south of the Solomon Islands, other A. australis (10.8-12.0 mm) larvae were caught northwest of Fiji along with an A. obscura (20.0 mm) larva, and an A. marmorata (7.8 mm) larva was collected near Samoa. Considering collection sites, larval ages from otolith analysis, and westward SEC drift, multiple spawning locations occurred from south of the Solomon Islands and the Fiji area (16-20 days old larvae) to near Samoa (19 days old larva) during June and July in areas where high-salinity Subtropical Underwater (STUW, ~150 m depth) and the warm, low-salinity surface Fresh Pool were present. Five long hydrographic sections showed the strong Fresh Pool in the west and the STUW formation area in the east.
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Affiliation(s)
- Mari Kuroki
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Michael J. Miller
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Eric Feunteun
- Muséum National d’Histoire Naturelle, BOREA (Biologie des Organismes et Ecosystèmes Aquatiques), Station marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France
| | - Pierre Sasal
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan Via Domitia, 58 Avenue Paul Alduy, 66860 Perpignan, France
| | - Timothy Pikering
- Secretariat of the Pacific Community, 3 Luke Street, Nabua, Suva, Fiji
| | - Yu-San Han
- Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Elisabeth Faliex
- Centre de Formation et de Recherche sur les Environnements Méditerranéens, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France
| | - Anthony Acou
- Muséum National d’Histoire Naturelle, BOREA (Biologie des Organismes et Ecosystèmes Aquatiques), Station marine de Dinard, 38 rue du Port Blanc, 35800 Dinard, France
- UMS Patrimoine Naturel (Patrinat), AFB-MNHN-CNRS, CP 41, 36 rue Geoffroy Saint-Hilaire, 75005 Paris, France
| | - Aurélie Dessier
- Université de La Rochelle, Batiment ILE, LIENSs, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | | | - Shun Watanabe
- Department of Fisheries, Faculty of Agriculture, Kindai University, Nara 631-8505, Japan
| | - Tatsuya Kawakami
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Hiroaki Onda
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Takatoshi Higuchi
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Aya Takeuchi
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Madoka Shimizu
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Chinthaka A. Hewavitharane
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- School of Marine Studies, Faculty of Science, The University of the South Pacific, Laucala Bay Road, Suva, Fiji
| | - Seishi Hagihara
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Terumasa Taka
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Shingo Kimura
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Noritaka Mochioka
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tsuguo Otake
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Katsumi Tsukamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
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Miller MJ, Westerberg H, Sparholt H, Wysujack K, Sørensen SR, Marohn L, Jacobsen MW, Freese M, Ayala DJ, Pohlmann JD, Svendsen JC, Watanabe S, Andersen L, Møller PR, Tsukamoto K, Munk P, Hanel R. Spawning by the European eel across 2000 km of the Sargasso Sea. Biol Lett 2019; 15:20180835. [PMID: 30966898 DOI: 10.1098/rsbl.2018.0835] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It has been known for about a century that European eels have a unique life history that includes offshore spawning in the Sargasso Sea about 5000-7000 km away from their juvenile and adult habitats in Europe and northern Africa. Recently hatched eel larvae were historically collected during Danish, German and American surveys in specific areas in the southern Sargasso Sea. During a 31 day period of March and April 2014, Danish and German research ships sampled for European eel larvae along 15 alternating transects of stations across the Sargasso Sea. The collection of recently hatched eel larvae (≤12 mm) from 70° W and eastward to 50° W showed that the European eel had been spawning across a 2000 km wide region of the North Atlantic Ocean. Historical collections made from 1921 to 2007 showed that small larvae had also previously been collected in this wide longitudinal zone, showing that the spatial extent of spawning has not diminished in recent decades, irrespective of the dramatic decline in recruitment. The use of such a wide spawning area may be related to variations in the onset of the silver eel spawning migration, individual differences in their long-term swimming ability, or aspects of larval drift.
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Affiliation(s)
- Michael J Miller
- 1 Department of Marine Science and Resources, Nihon University , Fujisawa 252-0880 , Japan
| | - Håkan Westerberg
- 2 Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences , Stångholmsvägen 2, 17893, Drottningholm , Sweden
| | - Henrik Sparholt
- 3 National Institute of Aquatic Resources, Technical University of Denmark , 2800 Lyngby , Denmark
| | - Klaus Wysujack
- 4 Thünen Institute of Fisheries Ecology , Herwigstrasse 31, 27572 Bremerhaven , Germany
| | - Sune R Sørensen
- 3 National Institute of Aquatic Resources, Technical University of Denmark , 2800 Lyngby , Denmark
| | - Lasse Marohn
- 4 Thünen Institute of Fisheries Ecology , Herwigstrasse 31, 27572 Bremerhaven , Germany
| | - Magnus W Jacobsen
- 5 National Institute of Aquatic Resources, Technical University of Denmark , 8600 Silkeborg , Denmark.,6 Department of Bioscience, Aarhus University , DK-8000 Aarhus C , Denmark
| | - Marko Freese
- 4 Thünen Institute of Fisheries Ecology , Herwigstrasse 31, 27572 Bremerhaven , Germany
| | - Daniel J Ayala
- 3 National Institute of Aquatic Resources, Technical University of Denmark , 2800 Lyngby , Denmark
| | - Jan-Dag Pohlmann
- 4 Thünen Institute of Fisheries Ecology , Herwigstrasse 31, 27572 Bremerhaven , Germany
| | - Jon C Svendsen
- 3 National Institute of Aquatic Resources, Technical University of Denmark , 2800 Lyngby , Denmark
| | - Shun Watanabe
- 7 Department of Fisheries, Kindai University , Nara 631-8505 , Japan
| | - Line Andersen
- 6 Department of Bioscience, Aarhus University , DK-8000 Aarhus C , Denmark
| | - Peter R Møller
- 8 Natural History Museum of Denmark, University of Copenhagen , 2100 Copenhagen , Denmark
| | - Katsumi Tsukamoto
- 1 Department of Marine Science and Resources, Nihon University , Fujisawa 252-0880 , Japan
| | - Peter Munk
- 3 National Institute of Aquatic Resources, Technical University of Denmark , 2800 Lyngby , Denmark
| | - Reinhold Hanel
- 4 Thünen Institute of Fisheries Ecology , Herwigstrasse 31, 27572 Bremerhaven , Germany
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Bracamonte SE, Johnston PR, Monaghan MT, Knopf K. Gene expression response to a nematode parasite in novel and native eel hosts. Ecol Evol 2019; 9:13069-13084. [PMID: 31871630 PMCID: PMC6912882 DOI: 10.1002/ece3.5728] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/19/2019] [Accepted: 09/19/2019] [Indexed: 01/19/2023] Open
Abstract
Invasive parasites are involved in population declines of new host species worldwide. The high susceptibilities observed in many novel hosts have been attributed to the lack of protective immunity to the parasites which native hosts acquired during their shared evolution. We experimentally infected Japanese eels (Anguilla japonica) and European eels (Anguilla anguilla) with Anguillicola crassus, a nematode parasite that is native to the Japanese eel and invasive in the European eel. We inferred gene expression changes in head kidney tissue from both species, using RNA-seq data to determine the responses at two time points during the early stages of infection (3 and 23 days postinfection). At both time points, the novel host modified the expression of a larger and functionally more diverse set of genes than the native host. Strikingly, the native host regulated immune gene expression only at the earlier time point and to a small extent while the novel host regulated these genes at both time points. A low number of differentially expressed immune genes, especially in the native host, suggest that a systemic immune response was of minor importance during the early stages of infection. Transcript abundance of genes involved in cell respiration was reduced in the novel host which may affect its ability to cope with harsh conditions and energetically demanding activities. The observed gene expression changes in response to a novel parasite that we observed in a fish follow a general pattern observed in amphibians and mammals, and suggest that the disruption of physiological processes, rather than the absence of an immediate immune response, is responsible for the higher susceptibility of the novel host.
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Affiliation(s)
- Seraina E. Bracamonte
- Leibniz‐Institute of Freshwater Ecology and Inland FisheriesBerlinGermany
- Berlin Center for Genomics in Biodiversity ResearchBerlinGermany
- Faculty of Life SciencesHumboldt‐Universität zu BerlinBerlinGermany
| | - Paul R. Johnston
- Leibniz‐Institute of Freshwater Ecology and Inland FisheriesBerlinGermany
- Berlin Center for Genomics in Biodiversity ResearchBerlinGermany
- Institut für BiologieFreie Universität BerlinBerlinGermany
| | - Michael T. Monaghan
- Leibniz‐Institute of Freshwater Ecology and Inland FisheriesBerlinGermany
- Berlin Center for Genomics in Biodiversity ResearchBerlinGermany
- Institut für BiologieFreie Universität BerlinBerlinGermany
| | - Klaus Knopf
- Leibniz‐Institute of Freshwater Ecology and Inland FisheriesBerlinGermany
- Faculty of Life SciencesHumboldt‐Universität zu BerlinBerlinGermany
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Cresci A, Durif CM, Paris CB, Shema SD, Skiftesvik AB, Browman HI. Glass eels ( Anguilla anguilla) imprint the magnetic direction of tidal currents from their juvenile estuaries. Commun Biol 2019; 2:366. [PMID: 31602415 PMCID: PMC6783477 DOI: 10.1038/s42003-019-0619-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/17/2019] [Indexed: 01/08/2023] Open
Abstract
The European eel (Anguilla anguilla) hatches in the Sargasso Sea and migrates to European and North African freshwater. As glass eels, they reach estuaries where they become pigmented. Glass eels use a tidal phase-dependent magnetic compass for orientation, but whether their magnetic direction is innate or imprinted during migration is unknown. We tested the hypothesis that glass eels imprint their tidal-dependent magnetic compass direction at the estuaries where they recruit. We collected 222 glass eels from estuaries flowing in different cardinal directions in Austevoll, Norway. We observed the orientation of the glass eels in a magnetic laboratory where the magnetic North was rotated. Glass eels oriented towards the magnetic direction of the prevailing tidal current occurring at their recruitment estuary. Glass eels use their magnetic compass to memorize the magnetic direction of tidal flows. This mechanism could help them to maintain their position in an estuary and to migrate upstream.
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Affiliation(s)
- Alessandro Cresci
- Department of Ocean Sciences, Rosenstiel School of Marine & Atmospheric Science, 4600 Rickenbacker, Causeway, FL 33149-1098 USA
- Institute of Marine Research, Austevoll Research Station, Sauganeset 16, N-5392 Storebø, Norway
| | - Caroline M. Durif
- Institute of Marine Research, Austevoll Research Station, Sauganeset 16, N-5392 Storebø, Norway
| | - Claire B. Paris
- Department of Ocean Sciences, Rosenstiel School of Marine & Atmospheric Science, 4600 Rickenbacker, Causeway, FL 33149-1098 USA
| | | | - Anne Berit Skiftesvik
- Institute of Marine Research, Austevoll Research Station, Sauganeset 16, N-5392 Storebø, Norway
| | - Howard I. Browman
- Institute of Marine Research, Austevoll Research Station, Sauganeset 16, N-5392 Storebø, Norway
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Vasconi M, Lopez A, Galimberti C, Moreno Rojas JM, Muñoz Redondo JM, Bellagamba F, Moretti VM. Authentication of farmed and wild european eel (Anguilla anguilla) by fatty acid profile and carbon and nitrogen isotopic analyses. Food Control 2019. [DOI: 10.1016/j.foodcont.2019.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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46
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New PCR primers for metabarcoding environmental DNA from freshwater eels, genus Anguilla. Sci Rep 2019; 9:7977. [PMID: 31138865 PMCID: PMC6538671 DOI: 10.1038/s41598-019-44402-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 05/16/2019] [Indexed: 11/09/2022] Open
Abstract
Freshwater eels of the genus Anguilla comprise 16 species that include three subspecies and are characterized by their unique catadromous life cycles. Their life histories and nocturnal life styles make it difficult to observe them in freshwater and marine habitats. To investigate their distribution and ecology in aquatic environments, we developed new PCR primers for metabarcoding environmental DNA (eDNA) from Anguilla. The new primers (MiEel) were designed for two conserved regions of the mitochondrial ATP6 gene, which amplify a variable region with sufficient interspecific variations ranging from five to 22 nucleotide differences (one to three nucleotide differences between three subspecies pairs). We confirmed the versatility of the MiEel primers for all freshwater eels using tissue DNA extracts when analyzed separately. The metabarcoding combined with the MiEel primers using mock communities enabled simultaneous detection of Anguilla at the species level. Analysis of eDNA samples from aquarium tanks, a controlled pond and natural rivers demonstrated that the MiEel metabarcoding could successfully detect the correct Anguilla species from water samples. These results suggested that eDNA metabarcoding with MiEel primers would be useful for non-invasively monitoring the presence of the endangered anguillid eels in aquatic environments where sampling surveys are difficult.
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47
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Dispersal Characteristics and Pathways of Japanese Glass Eel in the East Asian Continental Shelf. SUSTAINABILITY 2019. [DOI: 10.3390/su11092572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Japanese eel Anguilla japonica is an important aquaculture fish species in the East Asian countries of Japan, China, Korea, and Taiwan. All glass eel fry are captured from the wild and understanding the recruitment patterns of the glass eel is important. The larvae of A. japonica are passively transported to the East Asian Continental Shelf by the North Equatorial Current, the Kuroshio, the Kuroshio intrusion currents, and coastal currents. In each location, recruitment time is diverse: It is November in Taiwan and April in the Yalu River. How the glass eels reach recruitment areas remains poorly understood. Here, we combine information from larval ages based on otolith increments, simulated drifting paths on the East Asian Continental Shelf, and main fishing seasons in each location of East Asia. We identify five main recruitment blocks: (1) The main Kuroshio, (2) The Taiwan Strait Warm Current, (3) The Taiwan Warm Current, (4) The Yellow Sea Warm Current and (5) The branch of Yellow Sea Warm Current. The counted age of the glass eels is significantly underestimated for the later recruits, possibly due to the cessation of the otolith edge growth under low water temperatures. This study clarifies the eel’s larval characteristics and transport mechanisms in the East Asia Continental Shelf, providing important information for its recruitment dynamics in the marine stage.
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48
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Miller MJ, Marohn L, Wysujack K, Freese M, Pohlmann JD, Westerberg H, Tsukamoto K, Hanel R. Morphology and gut contents of anguillid and marine eel larvae in the Sargasso Sea. ZOOL ANZ 2019. [DOI: 10.1016/j.jcz.2019.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Watz J, Nilsson PA, Degerman E, Tamario C, Calles O. Climbing the ladder: an evaluation of three different anguillid eel climbing substrata and placement of upstream passage solutions at migration barriers. Anim Conserv 2019. [DOI: 10.1111/acv.12485] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Watz
- RivEM Department of Environmental and Life Sciences Karlstad University Karlstad Sweden
- Faculty of Environmental Earth Science Hokkaido University Sapporo Japan
| | - P. A. Nilsson
- RivEM Department of Environmental and Life Sciences Karlstad University Karlstad Sweden
- Department of Biology ‐ Aquatic Ecology Lund University Lund Sweden
| | - E. Degerman
- Department of Aquatic Resources Institute of Freshwater Research Swedish University of Agricultural Sciences Örebro Sweden
| | - C. Tamario
- Department of Aquatic Resources Institute of Freshwater Research Swedish University of Agricultural Sciences Örebro Sweden
| | - O. Calles
- RivEM Department of Environmental and Life Sciences Karlstad University Karlstad Sweden
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Weaning European glass eels (Anguilla anguilla) with plant protein-based diets and its effects on intestinal maturation. Comp Biochem Physiol A Mol Integr Physiol 2018; 228:43-50. [PMID: 30414916 DOI: 10.1016/j.cbpa.2018.10.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 10/30/2018] [Indexed: 11/22/2022]
Abstract
Weaning glass eels with compound diets (36% proteins, 16% lipids) differing in their fishmeal (FM) level (50, 75 and 100% FM replaced by a blend of plant proteins, PP) was compared to a group fed cod roe. Weaning lasted for 20 days and then, eels were fed compound diets for 70 days, whereas the other group was only fed cod roe (90 days). Diets were tested with four replicates and evaluated in terms of growth, survival, glass eels metamorphosis into elvers, oxidative stress status and activity of digestive enzymes. Although glass eels are traditionally fed with fish roe and progressively weaned onto compound diets, results revealed that this strategy should not be prolonged for a long time, since feeding glass eels with cod roe for 90 days negatively affected their growth (2 times lower than fish fed compound diets), delayed their metamorphosis, as well as the maturation of their digestive function as the ratio of alkaline phosphatase and leucine-alanine peptidase indicated. Weaning glass eels onto compound diets differing in their FM levels did not affect their growth, metamorphic stage nor the activity of pancreatic enzymes (total alkaline proteases, trypsin, bile salt-activated lipase and α-amylase), although 75% FM replacement by PP sources delayed the level of intestinal maturation in eels. In comparison to glass eels fed the 100% FM diet, survival was negatively affected in groups fed diets with 50 and 75% FM replacement by PP ingredients, which indicated that further improvement is needed in diet formulation for this stage of development.
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