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Rademaker M, van Leeuwen A, Smallegange IM. Why we cannot always expect life history strategies to directly inform on sensitivity to environmental change. J Anim Ecol 2024; 93:348-366. [PMID: 38303132 DOI: 10.1111/1365-2656.14050] [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: 02/07/2023] [Accepted: 12/20/2023] [Indexed: 02/03/2024]
Abstract
Variation in life history traits in animals and plants can often be structured along major axes of life history strategies. The position of a species along these axes can inform on their sensitivity to environmental change. For example, species with slow life histories are found to be less sensitive in their long-term population responses to environmental change than species with fast life histories. This provides a tantalizing link between sets of traits and population responses to change, contained in a highly generalizable theoretical framework. Life history strategies are assumed to reflect the outcome of life history tradeoffs that, by their very nature, act at the individual level. Examples include the tradeoff between current and future reproductive success, and allocating energy into growth versus reproduction. But the importance of such tradeoffs in structuring population-level responses to environmental change remains understudied. We aim to increase our understanding of the link between individual-level life history tradeoffs and the structuring of life history strategies across species, as well as the underlying links to population responses to environmental change. We find that the classical association between lifehistory strategies and population responses to environmental change breaks down when accounting for individual-level tradeoffs and energy allocation. Therefore, projecting population responses to environmental change should not be inferred based only on a limited set of species traits. We summarize our perspective and a way forward in a conceptual framework.
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Affiliation(s)
- Mark Rademaker
- Department of Coastal Systems, Royal NIOZ and Utrecht University, Texel, The Netherlands
| | - Anieke van Leeuwen
- Department of Coastal Systems, Royal NIOZ and Utrecht University, Texel, The Netherlands
| | - Isabel M Smallegange
- School of Natural & Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
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2
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Bandara KA, Politis SN, Sørensen SR, Benini E, Tomkiewicz J, Vadstein O. Effect of Food Amounts on Larval Performance, Bacteriome and Molecular Immunologic Development during First-Feeding Culture of European Eel. Microorganisms 2024; 12:355. [PMID: 38399759 PMCID: PMC10892360 DOI: 10.3390/microorganisms12020355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Production of European eel offspring has become a reality, but liquid diets during larval culture hold new challenges. This study focused on increasing food amounts without compromising well-being or healthy larvae-bacteria interactions. First-feeding larvae were fed two food amounts (Low = 0.5 mL food/L water vs. High = 1.5 mL food/L water) until 30 days post-hatch (dph). Results indicated that ~75% of larvae ingested the diet in both treatments, but upregulation of a stress/repair-related gene (hsp90) on 25 and 30 dph indicated nutritional inadequacy. Larvae fed a High amount of food were 3.68% bigger, while larvae in the Low-food group showed 45.2% lower gut fullness and upregulated expression of the gene encoding the "hunger hormone" ghrelin (ghrl), indicating signs of starvation. The High-food group larvae exhibited a healthier bacteriome with a higher abundance of potentially beneficial orders (Lactobacillales and Bacillales), whereas the Low-food group showed more potentially harmful orders (Vibrionales, Rhodobacterales, and Alteromonadales). While survival was initially lower in the High-food group, both treatments had comparable survival by the end of the experiment. In conclusion, feeding European eel larvae with High food amounts seemed beneficial, supported by increased gut fullness, reduced ghrl expression (no starvation), enhanced growth, and the presence of a healthier bacteriome.
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Affiliation(s)
- Kasun Anuruddha Bandara
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Sebastian Nikitas Politis
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Sune Riis Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Elisa Benini
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Olav Vadstein
- Department of Biotechnology and Food Science, NTNU—Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Asiedu DA, Søndergaard J, Jónasdóttir S, Juul-Pedersen T, Koski M. Concentration of mercury and other metals in an Arctic planktonic food web under a climate warming scenario. MARINE POLLUTION BULLETIN 2023; 194:115436. [PMID: 37660452 DOI: 10.1016/j.marpolbul.2023.115436] [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: 06/15/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 09/05/2023]
Abstract
Arctic marine ecosystems act as a global sink of mercury (Hg) and other metals, and high concentrations of these have been measured in higher trophic-level organisms. Nevertheless, the concentrations of metals at the basis of the marine food web in the Arctic is less known despite the likelihood of biomagnification from dietary sources. We investigated the concentrations of mercury (Hg) and other metals in different size fractions of plankton in West Greenland. All size fractions contained detectable levels of Hg (ranging from 4.8 to 241.3 ng g dw-1) at all stations, although with high geographic variability, likely reflecting the sources of mercury (e.g., meltwater). In many cases, the concentrations in the larger-size fractions were lower than in the smaller-size fractions, suggesting depuration through the metabolic activity of mesozooplankton. Concentrations of Cd, Pb, V, Ni, and Cr were higher than previously reported elsewhere in the Arctic.
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Affiliation(s)
- Delove Abraham Asiedu
- National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Jens Søndergaard
- Department of Ecoscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Sigrun Jónasdóttir
- National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Thomas Juul-Pedersen
- Greenland Climate Research Center, Greenland Institute of Natural Resources, Nuuk 3900, Greenland
| | - Marja Koski
- National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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4
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Bandara KA, Benini E, Politis SN, Conceição LEC, Santos A, Sørensen SR, Tomkiewicz J, Vadstein O. Exploring bacterial community composition and immune gene expression of European eel larvae (Anguilla anguilla) in relation to first-feeding diets. PLoS One 2023; 18:e0288734. [PMID: 37498931 PMCID: PMC10373994 DOI: 10.1371/journal.pone.0288734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023] Open
Abstract
European eel (Anguilla anguilla) is a commercially important species for fisheries and aquaculture in Europe and the attempt to close the lifecycle in captivity is still at pioneering stage. The first feeding stage of this species is characterized by a critical period between 20 to 24 days post hatch (dph), which is associated with mortalities, indicating the point of no return. We hypothesized that this critical period might also be associated with larvae-bacterial interactions and the larval immune status. To test this, bacterial community composition and expression of immune and stress-related genes of hatchery-produced larvae were explored from the end of endogenous feeding (9 dph) until 28 dph, in response to three experimental first-feeding diets (Diet 1, Diet 2 and Diet 3). Changes in the water bacterial community composition were also followed. Results revealed that the larval stress/repair mechanism was activated during this critical period, marked by an upregulated expression of the hsp90 gene, independent of the diet fed. At the same time, a shift towards a potentially detrimental larval bacterial community was observed in all dietary groups. Here, a significant reduction in evenness of the larval bacterial community was observed, and several amplicon sequence variants belonging to potentially harmful bacterial genera were more abundant. This indicates that detrimental larvae-bacteria interactions were likely involved in the mortality observed. Beyond the critical period, the highest survival was registered for larvae fed Diet 3. Interestingly, genes encoding for pathogen recognition receptor TLR18 and complement component C1QC were upregulated in this group, potentially indicating a higher immunocompetency that facilitated a more successful handling of the harmful bacteria that dominated the bacterial community of larvae on 22 dph, ultimately leading to better survival, compared to the other two groups.
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Affiliation(s)
- Kasun A Bandara
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
- Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Elisa Benini
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Sebastian N Politis
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | | | - André Santos
- SPAROS Lda, Área Empresarial de Marim, Lote C, Olhão, Portugal
| | - Sune Riis Sørensen
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Jonna Tomkiewicz
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Olav Vadstein
- Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
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5
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Roura Á, Doyle SR, Castro-Bugallo A, Hall NE, Gonzalez ÁF, Strugnell JM. Trophic ecology of Octopus vulgaris paralarvae along the Iberian Canary current eastern boundary upwelling system. Sci Rep 2023; 13:8744. [PMID: 37253926 PMCID: PMC10229560 DOI: 10.1038/s41598-023-35206-4] [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: 10/20/2022] [Accepted: 05/14/2023] [Indexed: 06/01/2023] Open
Abstract
Our knowledge of the diet of wild octopus paralarvae, Octopus vulgaris, is restricted to the first 2 weeks of its planktonic phase when they are selective hunters found near the coastline. These small paralarvae, bearing only three suckers per arm, are transported by oceanic currents from the coast towards offshore waters, where they complete the planktonic phase over 2 months. Here, we have investigated the trophic ecology of O. vulgaris paralarvae in two contrasting upwelling sub-regions of the Iberian Canary current (ICC) eastern boundary upwelling system and have evaluated dietary change as paralarvae develop (inferred by counting the number of suckers per arm, ranging from three to 15) along the coastal-oceanic gradient during their planktonic phase. Using high-throughput amplicon sequencing, we have characterised the diet of 100 paralarvae collected along the Northwest Iberian Peninsula (n = 65, three to five suckers per arm) and off the west coast of Morocco (n = 35, three to 15 suckers per arm), identifying up to 87 different prey species. The diet of paralarvae varied along the ICC, with crabs (53.4%), siphonophores (12.2%), copepods (12.3%), cnidarians (8.4%) and pteropods (3.7%) accounting for 90% of the variability detected off NW Iberian Peninsula, whereas off W Morocco, crabs (46.2%), copepods (23.1%), cnidarians (12.9%), krill (9.3%) and fishes (4.2%) explained 95.6% of the variability observed using frequency of observance (FOO%) data. Ontogenetic changes in the diet based on groups of paralarvae with similar numbers per arm were evidenced by the decreasing contribution of coastal meroplankton and an increase in oceanic holoplankton, including siphonophores, copepods, pteropods and krill. Trophic niche breadth values ranged from 0.06 to 0.67, with averaged values ranging from 0.23 to 0.33 (generalist = 1 and specialist = 0), suggesting that O. vulgaris paralarvae are selective predators through their ontogenetic transition between coastal and oceanic environments.
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Affiliation(s)
- Álvaro Roura
- La Trobe University, Melbourne, VIC, 3086, Australia.
- Ecology and Marine Resources, Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello 6, 36208, Vigo, Spain.
| | - Stephen R Doyle
- Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | | | - Nathan E Hall
- La Trobe University, Melbourne, VIC, 3086, Australia
- GMDx Group Ltd, Melbourne, VIC, Australia
| | - Ángel F Gonzalez
- Ecology and Marine Resources, Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello 6, 36208, Vigo, Spain
| | - Jan M Strugnell
- La Trobe University, Melbourne, VIC, 3086, Australia
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, QLD, 4810, Australia
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Beckmann LM, Soto-Angel JJ, Hosia A, Martell L. Odd family reunion: DNA barcoding reveals unexpected relationship between three hydrozoan species. PeerJ 2023; 11:e15118. [PMID: 37065693 PMCID: PMC10100810 DOI: 10.7717/peerj.15118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/02/2023] [Indexed: 04/18/2023] Open
Abstract
Knowledge of life histories is crucial for understanding ecological and evolutionary processes, but for many hydrozoan species only incomplete life cycles have been described due to challenges in linking hydromedusae with their polyp stages. Using a combination of DNA barcoding, morphology, and ecological information, we describe for the first time the polyp stage of Halopsis ocellata Agassiz, 1865 and re-describe that of Mitrocomella polydiademata (Romanes, 1876). Campanulinid hydroids referable to Lafoeina tenuis Sars, 1874 and collected in the same biogeographic region as the type locality of this species are shown to be the polyp stage of these two mitrocomid hydromedusae. The nominal species L. tenuis thus is a species complex that includes the polyp stage of medusae belonging to at least two genera currently placed in a different family. Consistent morphological and ecological differences were found between the polyps linked to each of these two hydromedusae, but molecular results suggest that yet other species may have morphologically similar hydroids. Polyps morphologically identified to L. tenuis are therefore better referred to as Lafoeina tenuis-type until further associations are resolved, particularly when occurring outside of the area of distribution of H. ocellata and M. polydiademata. Molecular identification integrated with traditional taxonomy is confirmed as an effective approach to link inconspicuous stages of marine invertebrates with hitherto unknown life cycles, especially in often-overlooked taxa. Disentangling the relationships between L. tenuis, H. ocellata, and M. polydiademata lays the ground for future research aimed at resolving the taxonomy and systematics of the enigmatic families Mitrocomidae and Campanulinidae.
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Stoner EW, Archer SK, Layman CA. Increased nutrient availability correlates with increased growth of the benthic jellyfish Cassiopea spp. FOOD WEBS 2022. [DOI: 10.1016/j.fooweb.2022.e00231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lüskow F, Christiansen B, Chi X, Silva P, Neitzel P, Brooks ME, Jaspers C. Distribution and biomass of gelatinous zooplankton in relation to an oxygen minimum zone and a shallow seamount in the Eastern Tropical North Atlantic Ocean. MARINE ENVIRONMENTAL RESEARCH 2022; 175:105566. [PMID: 35123181 DOI: 10.1016/j.marenvres.2022.105566] [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: 04/16/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
Physical and topographic characteristics can structure pelagic habitats and affect the plankton community composition. For example, oxygen minimum zones (OMZs) are expected to lead to a habitat compression for species with a high oxygen demand, while upwelling of nutrient-rich deep water at seamounts can locally increase productivity, especially in oligotrophic oceanic waters. Here we investigate the response of the gelatinous zooplankton (GZ) assemblage and biomass to differing oxygen conditions and to a seamount in the Eastern Tropical North Atlantic (ETNA) around the Cape Verde archipelago. A total of 16 GZ taxa (>1100 specimens) were found in the upper 1000 m with distinct species-specific differences, such as the absence of deep-living species Atolla wyvillei and Periphylla periphylla above the shallow seamount summit. Statistical analyses considering the most prominent groups, present at all stations, namely Beroe spp., hydromedusae (including Zygocanna vagans, Halicreas minimum, Colobonema sericeum, Solmissus spp.) and total GZ, showed a strong positive correlation of abundance with temperature for all groups, whereas oxygen had a weak negative correlation only with abundances of Beroe spp. and hydromedusae. To account for size differences between species, we established length-weight regressions and investigated total GZ biomass changes in relation to physical (OMZ) and topographic characteristics. The highest GZ biomass was observed at depths of lowest oxygen concentrations and deepest depth strata at the southeastern flank of the seamount and at two stations south of the Cape Verde archipelago. Our data suggest that, irrespective of their patchy distribution, GZ organisms are ubiquitous food web members of the ETNA, and their habitat includes waters of low oxygen content.
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Affiliation(s)
- Florian Lüskow
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2039-2207 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada; Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Bernd Christiansen
- Institute of Marine Ecosystem and Fishery Science, Universität Hamburg, Große Elbstraße 133, 22767, Hamburg, Germany
| | - Xupeng Chi
- GEOMAR, Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany; Key Laboratory of Marine Ecology & Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Nanhai Road 7, Qingdao, 266071, China
| | - Péricles Silva
- Instituto Nacional de Desenvolvimento das Pescas, Cova da Inglesa, CP132, Mindelo, São Vicente, Cape Verde
| | - Philipp Neitzel
- GEOMAR, Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany
| | - Mollie E Brooks
- National Institute of Aquatic Resources, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Cornelia Jaspers
- Centre for Gelatinous Plankton Ecology & Evolution, National Institute of Aquatic Resources, Technical University of Denmark, Kemitorvet, 2800, Kgs. Lyngby, Denmark.
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Kenzaki A, Okunishi S, Tomoda T, Shioura Y, Uchida M, Tezuka N, Maeda H. Observation of the feeding behaviour of reared Japanese eel Anguilla japonica leptocephali fed picocyanobacteria Synechococcus spp. JOURNAL OF FISH BIOLOGY 2022; 100:727-737. [PMID: 34958491 DOI: 10.1111/jfb.14986] [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: 07/01/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
The authors observed the feeding behaviour of artificially reared Japanese eel Anguilla japonica leptocephali, 7.5-19 mm total length (10-61 days post-hatch), fed Synechococcus sp., which is considered a potential food source of anguilliform larvae. Three strains of Synechococcus sp. (NIES-972, 976 and 979) were tested as the food material. Larvae across the entire length range could effectively ingest a suspension of pico-sized cyanobacteria (1-3 μm in diameter). Video observations of the mid-hindgut of larvae under an epifluorescence microscope confirmed that the movement of microvilli of the intestinal epithelium allowed the cell particles to circulate in the mid-hindgut, before becoming solidified in the anal region. Significant differences in food intake were observed between larvae fed two strains of Synechococcus (NIES-972 and 976), and among different cell densities, which suggests feeding selectivity and density dependence. Comparisons of feeding behaviour under the light group (9L:15D) and the dark group (24D) showed significantly higher food intake (measured as an index of intestinal fullness) in the light group, although substantial and continuous ingestion was observed in the dark group, indicating continuous feeding by swallowing sea water. The authors hypothesise that the feeding ecology of anguilliform leptocephali is based on a survival strategy whereby the larvae do not compete with various higher-trophic-level fishes for food in an oligotrophic environment.
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Affiliation(s)
- Akira Kenzaki
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima, Japan
| | - Suguru Okunishi
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
| | - Tsutomu Tomoda
- Glass Eel Production Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, Kagoshima, Japan
| | - Yuuya Shioura
- Glass Eel Production Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, Kagoshima, Japan
| | - Motoharu Uchida
- Momoshima Field Station, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, Hiroshima, Japan
| | - Naoaki Tezuka
- Coastal and Inland Fisheries Ecosystems Division, Fisheries Technology Institute, National Research and Development Agency, Fisheries Research and Education Agency, Hiroshima, Japan
| | - Hiroto Maeda
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
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Günther B, Fromentin JM, Metral L, Arnaud-Haond S. Metabarcoding confirms the opportunistic foraging behaviour of Atlantic bluefin tuna and reveals the importance of gelatinous prey. PeerJ 2021; 9:e11757. [PMID: 34447617 PMCID: PMC8366523 DOI: 10.7717/peerj.11757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/21/2021] [Indexed: 12/22/2022] Open
Abstract
Studies of the diet, feeding habits and trophic activity of top marine predators are essential for understanding their trophodynamics. The main direct method used for such studies thus far has been morphological inventories of stomach contents. This approach presents limitations such as missing gelatinous prey, which are usually digested too quickly to be detectable. Here, we analysed the stomachs of 48 Atlantic bluefin tuna (Thunnus thynnus, approximately 15 to 60 kg, including juveniles and adult fishes) collected from the Mediterranean Sea through the metabarcoding of two gene regions (cytochrome c oxidase subunit I (COI) and the ribosomal 18S-V1V2 region). The identified prey taxa and their relative read abundances (RRAs) estimated using COI results were in line with the findings of morphologically based inventories simultaneously performed on the same set of tuna samples. In both cases (and with the same rankings), the prey taxa included anchovy (Engraulis encrasicolus, here detected in more than 80% of samples, RRA = 43%), sardine (Sardina pilchardus, also approximately 80%, RRA = 30%), sprat (Sprattus sprattus, approximately 66%, RRA = 8%), mackerel (Scomber colias, approximately 44%, RRA = 7%) and cephalopods (approximately 15%, RRA = 1.4%). Another striking result was the detection, based on 18S (with which vertebrates were detected as the most abundant group, RRA = 61.6%), of a high prevalence and diversity of gelatinous organisms (RRA = 27.1%), including cnidarians (6.7%), salps (11.7%), and ctenophores (8.7%), the latter increasing with the size of the predator. These results thus support the hypothesis of the role of gelatinous prey in the diet of Atlantic bluefin tuna, suggesting that this species is even more generalist and opportunistic than previously thought. This study further confirms that DNA metabarcoding can be a powerful tool for assessing the diet and trophodynamics of top marine predators.
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Affiliation(s)
- Babett Günther
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France
| | | | - Luisa Metral
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France
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11
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18S rRNA gene sequences of leptocephalus gut contents, particulate organic matter, and biological oceanographic conditions in the western North Pacific. Sci Rep 2021; 11:5488. [PMID: 33658626 PMCID: PMC7930194 DOI: 10.1038/s41598-021-84532-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 02/15/2021] [Indexed: 11/09/2022] Open
Abstract
Eel larvae apparently feed on marine snow, but many aspects of their feeding ecology remain unknown. The eukaryotic 18S rRNA gene sequence compositions in the gut contents of four taxa of anguilliform eel larvae were compared with the sequence compositions of vertically sampled seawater particulate organic matter (POM) in the oligotrophic western North Pacific Ocean. Both gut contents and POM were mainly composed of dinoflagellates as well as other phytoplankton (cryptophytes and diatoms) and zooplankton (ciliophoran and copepod) sequences. Gut contents also contained cryptophyte and ciliophoran genera and a few other taxa. Dinoflagellates (family Gymnodiniaceae) may be an important food source and these phytoplankton were predominant in gut contents and POM as evidenced by DNA analysis and phytoplankton cell counting. The compositions of the gut contents were not specific to the species of eel larvae or the different sampling areas, and they were most similar to POM at the chlorophyll maximum in the upper part of the thermocline (mean depth: 112 m). Our results are consistent with eel larvae feeding on marine snow at a low trophic level, and feeding may frequently occur in the chlorophyll maximum in the western North Pacific.
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12
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New clues on the Atlantic eels spawning behavior and area: the Mid-Atlantic Ridge hypothesis. Sci Rep 2020; 10:15981. [PMID: 33024193 PMCID: PMC7538991 DOI: 10.1038/s41598-020-72916-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
The Sargasso Sea has long been considered as the only spawning area for Atlantic eels, despite the absence of direct observations. The present study raises a novel scenario, deviating from Schmidt’s dogma, begins with a review of historical and recent observations that were combined to build up a global theory on spawning ecology and migration behavior of Atlantic eels. From this, it is argued that a favorable spawning area could be located eastward of Sargasso Sea at the intersection between the Mid-Atlantic Ridge and the oceanic fronts. Ocean circulation models combined with 3D particle-tracking method confirmed that spawning at this specific area would result in larval distribution fitting the field observation. This study explores the hypothesis that leptocephali are able to swim and orientate to reach their specific growth areas. It proposes a novel framework about spawning ecology, based on orientation, navigation and meeting cues of silver eels to the spawning area. Together this framework may serve as a stepping-stone for solving the long-lasting mystery of eel reproduction which first came out 2,400 years ago and promotes the understanding of oceanic migration and reproduction of marine organisms.
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Šćekić I, Marinović Z, Lujić J, Müller T, Kitanović N, Urbányi B, Horváth Á. A novel strategy for conservation of European eel (Anguilla anguilla) genetic resources: Cryopreservation of ovarian stem cells. Cryobiology 2020; 95:151-156. [DOI: 10.1016/j.cryobiol.2020.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 11/30/2022]
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Marques R, Darnaude AM, Crochemore S, Bouvier C, Bonnet D. Molecular approach indicates consumption of jellyfish by commercially important fish species in a coastal Mediterranean lagoon. MARINE ENVIRONMENTAL RESEARCH 2019; 152:104787. [PMID: 31522875 DOI: 10.1016/j.marenvres.2019.104787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/05/2019] [Accepted: 09/07/2019] [Indexed: 06/10/2023]
Abstract
Until recently, jellyfish have been ignored as an important source of food, due to their low nutritional value. Here, quantitative PCR was used to detect and quantify the DNA of the jellyfish Aurelia coerulea in the gut contents of commercially important fish species from the Thau Lagoon. Individuals from five fish species were collected during two different periods: the bloom period, when the pelagic stages of A. coerulea are abundant, and the post-bloom period, when only the benthic stage - polyps - is present in the lagoon. The DNA of A. coerulea was detected in the guts of 41.9% of the fish analysed, belonging to four different species. The eel Anguilla anguilla and the seabream Sparus aurata were important jellyfish consumers during the bloom and post-bloom periods, respectively. These results provide new insights on the potential control of jellyfish populations and on jellyfish importance as a food source for exploited fishes.
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Affiliation(s)
- Raquel Marques
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France.
| | | | | | - Corinne Bouvier
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - Delphine Bonnet
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
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15
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Chow S, Inaba N, Nagai S, Kurogi H, Nakamura Y, Yanagimoto T, Tanaka H, Hasegawa D, Asakura T, Kikuchi J, Tomoda T, Kodama T. Molecular diet analysis of Anguilliformes leptocephalus larvae collected in the western North Pacific. PLoS One 2019; 14:e0225610. [PMID: 31774866 PMCID: PMC6881025 DOI: 10.1371/journal.pone.0225610] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/07/2019] [Indexed: 11/18/2022] Open
Abstract
Natural diets of leptocephalus larvae have been enigmatic. In this study, we collected DNA samples from the gut contents and body surface of leptocephali belonging to the five Anguilliform families (Anguillidae, Chlopsidae, Congridae, Muraenidae, and Serrivomeridae) from the northwest Pacific and performed next-generation 18S rDNA sequencing. Wide variety of eukaryotes was detected in both samples, from which eight eukaryotic groups (jellyfish, conoid parasite, tunicate, copepod, krill, segmented worm, fungi, and dinoflagellate) were selected on the basis of abundance. All groups except conoid parasites were common in both the samples. Cnidarian 18S rDNA reads were the most abundant in both the samples; however, the number of samples having cnidarian reads and the read counts were significantly higher in the body surface scraping samples than in the gut content samples, regardless of careful rinsing of the body surface. These results indicate that the cnidarian DNAs are most likely found because of cross contamination from the body surface and/or environment. 18S rDNA read counts of copepod and tunicate in the gut contents were greater than or comparable with those in the body surface scraping samples, which may correspond to the previous observations of fecal pellets and larvacean houses in the leptocephali gut. Thus, the present study supports previous implications that leptocephali utilize detritus materials, so called marine snow.
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Affiliation(s)
- Seinen Chow
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
- * E-mail:
| | - Nobuharu Inaba
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
- Civil Engineering Research Institute for Cold Region, Public Works Research Institute, Sapporo, Hokkaido, Japan
| | - Satoshi Nagai
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
| | - Hiroaki Kurogi
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
| | - Yoji Nakamura
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
| | - Takashi Yanagimoto
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
| | - Hideki Tanaka
- Aquaculture Research Institute, Kindai University, Higashimuro, Wakayama, Japan
| | - Daisuke Hasegawa
- Tohoku National Fisheries Research Institute, Japan Fisheries Research and Education Agency, Shiogama, Miyagi, Japan
| | - Taiga Asakura
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Tsutomu Tomoda
- Shibushi Station, National Research Institute of Aquaculture, Japan Fisheries Research and Education Agency, Shibushi, Kagoshima, Japan
| | - Taketoshi Kodama
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Kanazawa, Yokohama, Japan
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16
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Lundgreen RBC, Jaspers C, Traving SJ, Ayala DJ, Lombard F, Grossart HP, Nielsen TG, Munk P, Riemann L. Eukaryotic and cyanobacterial communities associated with marine snow particles in the oligotrophic Sargasso Sea. Sci Rep 2019; 9:8891. [PMID: 31222051 PMCID: PMC6586830 DOI: 10.1038/s41598-019-45146-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 05/31/2019] [Indexed: 11/09/2022] Open
Abstract
Marine snow aggregates represent heterogeneous agglomerates of dead and living organic matter. Composition is decisive for their sinking rates, and thereby for carbon flux to the deep sea. For oligotrophic oceans, information on aggregate composition is particularly sparse. To address this, the taxonomic composition of aggregates collected from the subtropical and oligotrophic Sargasso Sea (Atlantic Ocean) was characterized by 16S and 18S rRNA gene sequencing. Taxonomy assignment was aided by a collection of the contemporary plankton community consisting of 75 morphologically and genetically identified plankton specimens. The diverse rRNA gene reads of marine snow aggregates, not considering Trichodesmium puffs, were dominated by copepods (52%), cnidarians (21%), radiolarians (11%), and alveolates (8%), with sporadic contributions by cyanobacteria, suggesting a different aggregate composition than in eutrophic regions. Composition linked significantly with sampling location but not to any measured environmental parameters or plankton biomass composition. Nevertheless, indicator and network analyses identified key roles of a few rare taxa. This points to complex regulation of aggregate composition, conceivably affected by the environment and plankton characteristics. The extent to which this has implications for particle densities, and consequently for sinking rates and carbon sequestration in oligotrophic waters, needs further interrogation.
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Affiliation(s)
- Regitze B C Lundgreen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.,National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Cornelia Jaspers
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Evolutionary Ecology of Marine Fishes, Kiel, Germany.,National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Sachia J Traving
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Daniel J Ayala
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Fabien Lombard
- Sorbonne Université, CNRS-INSU, Laboratoire d'Océanographie de Villefranche, LOV UMR 7093, F-06230, Villefranche-sur-mer, France
| | - Hans-Peter Grossart
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) Berlin, Stechlin, Germany.,Potsdam University, Institute for Biochemistry and Biology, Potsdam, Germany
| | - Torkel G Nielsen
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Peter Munk
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
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17
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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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18
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Hays GC, Doyle TK, Houghton JD. A Paradigm Shift in the Trophic Importance of Jellyfish? Trends Ecol Evol 2018; 33:874-884. [DOI: 10.1016/j.tree.2018.09.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/03/2018] [Accepted: 09/03/2018] [Indexed: 12/22/2022]
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