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Woronowicz KC, Esin EV, Markevich GN, Martinez CS, McMenamin SK, Daane JM, Harris MP, Shkil FN. Phylogenomic analysis of the Lake Kronotskoe species flock of Dolly Varden charr reveals genetic and developmental signatures of sympatric radiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.24.529919. [PMID: 38712299 PMCID: PMC11071292 DOI: 10.1101/2023.02.24.529919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Recent adaptive radiations provide evolutionary case studies, which provide the context to parse the relationship between genomic variation and the origins of distinct phenotypes. Sympatric radiations of the charr complex (genus Salvelinus) present a trove for phylogenetics as charrs have repeatedly diversified into multiple morphs with distinct feeding specializations. However, species flocks normally comprise only two to three lineages. Dolly Varden charr inhabiting Lake Kronotske represent the most extensive radiation described for the charr genus, containing at least seven lineages, each with defining morphological and ecological traits. Here, we perform the first genome-wide analysis of this species flock to parse the foundations of adaptive change. Our data support distinct, reproductively isolated lineages with little evidence of hybridization. We also find that specific selection on thyroid signaling and craniofacial genes forms a genomic basis for the radiation. Thyroid hormone is further implicated in subsequent lineage partitioning events. These results delineate a clear genetic basis for the diversification of specialized lineages, and highlight the role of developmental mechanisms in shaping the forms generated during adaptive radiation.
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Affiliation(s)
- Katherine C Woronowicz
- Department of Orthopaedics, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Evgeny V Esin
- AN Severtsov Institute of Ecology and Evolution, RAS; Leninskiy-33, 119071 Moscow, Russian Federation
| | - Grigorii N Markevich
- Kronotsky Nature Biosphere Reserve; Ryabikova-48, 68400 Yelizovo, Russian Federation
| | | | | | - Jacob M Daane
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Matthew P Harris
- Department of Orthopaedics, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Fedor N Shkil
- AN Severtsov Institute of Ecology and Evolution, RAS; Leninskiy-33, 119071 Moscow, Russian Federation
- NK Koltzov Institute of Developmental Biology, RAS; Vavilova-26, 119334 Moscow, Russian Federation
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2
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Moccetti P, Rodger JR, Bolland JD, Kaiser-Wilks P, Smith R, Nunn AD, Adams CE, Bright JA, Honkanen HM, Lothian AJ, Newton M, Joyce DA. Is shape in the eye of the beholder? Assessing landmarking error in geometric morphometric analyses on live fish. PeerJ 2023; 11:e15545. [PMID: 37605749 PMCID: PMC10440062 DOI: 10.7717/peerj.15545] [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: 10/14/2022] [Accepted: 05/22/2023] [Indexed: 08/23/2023] Open
Abstract
Geometric morphometrics is widely used to quantify morphological variation between biological specimens, but the fundamental influence of operator bias on data reproducibility is rarely considered, particularly in studies using photographs of live animals taken under field conditions. We examined this using four independent operators that applied an identical landmarking scheme to replicate photographs of 291 live Atlantic salmon (Salmo salar L.) from two rivers. Using repeated measures tests, we found significant inter-operator differences in mean body shape, suggesting that the operators introduced a systematic error despite following the same landmarking scheme. No significant differences were detected when the landmarking process was repeated by the same operator on a random subset of photographs. Importantly, in spite of significant operator bias, small but statistically significant morphological differences between fish from the two rivers were found consistently by all operators. Pairwise tests of angles of vectors of shape change showed that these between-river differences in body shape were analogous across operator datasets, suggesting a general reproducibility of findings obtained by geometric morphometric studies. In contrast, merging landmark data when fish from each river are digitised by different operators had a significant impact on downstream analyses, highlighting an intrinsic risk of bias. Overall, we show that, even when significant inter-operator error is introduced during digitisation, following an identical landmarking scheme can identify morphological differences between populations. This study indicates that operators digitising at least a sub-set of all data groups of interest may be an effective way of mitigating inter-operator error and potentially enabling data sharing.
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Affiliation(s)
- Paolo Moccetti
- Evolutionary and Ecological Genomics Group, School of Natural Sciences, University of Hull, Hull, United Kingdom
- Hull International Fisheries Institute, School of Natural Sciences, University of Hull, Hull, United Kingdom
- Energy and Environment Institute, University of Hull, Hull, United Kingdom
| | - Jessica R. Rodger
- Atlantic Salmon Trust Fellow, Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Jonathan D. Bolland
- Hull International Fisheries Institute, School of Natural Sciences, University of Hull, Hull, United Kingdom
| | - Phoebe Kaiser-Wilks
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Rowan Smith
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Andy D. Nunn
- Hull International Fisheries Institute, School of Natural Sciences, University of Hull, Hull, United Kingdom
| | - Colin E. Adams
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Jen A. Bright
- School of Natural Sciences, University of Hull, Hull, United Kingdom
| | - Hannele M. Honkanen
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Angus J. Lothian
- Atlantic Salmon Trust Fellow, Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Matthew Newton
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Domino A. Joyce
- Evolutionary and Ecological Genomics Group, School of Natural Sciences, University of Hull, Hull, United Kingdom
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3
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Secci-Petretto G, Englmaier GK, Weiss SJ, Antonov A, Persat H, Denys GPJ, Schenekar T, Romanov VI, Taylor EB, Froufe E. Evaluating a species phylogeny using ddRAD SNPs: Cyto-nuclear discordance and introgression in the salmonid genus Thymallus (Salmonidae). Mol Phylogenet Evol 2023; 178:107654. [PMID: 36336233 DOI: 10.1016/j.ympev.2022.107654] [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: 06/10/2022] [Revised: 10/05/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Hybridization and introgression are very common among freshwater fishes due to the dynamic nature of hydrological landscapes. Cyclic patterns of allopatry and secondary contact provide numerous opportunities for interspecific gene flow, which can lead to discordant paths of evolution for mitochondrial and nuclear genomes. Here, we used double digest restriction-site associated DNA sequencing (ddRADseq) to obtain a genome-wide single nucleotide polymorphism (SNP) dataset comprehensive for allThymallus (Salmonidae)species to infer phylogenetic relationships and evaluate potential recent and historical gene flow among species. The newly obtained nuclear phylogeny was largely concordant with a previously published mitogenome-based topology but revealed a few cyto-nuclear discordances. These incongruencies primarily involved the placement of internal nodes rather than the resolution of species, except for one European species where anthropogenic stock transfers are thought to be responsible for the observed pattern. The analysis of four contact zones where multiple species are found revealed a few cases of mitochondrial capture and limited signals of nuclear introgression. Interestingly, the mechanisms restricting interspecific gene flow might be distinct; while in zones of secondary contact, small-scale physical habitat separation appeared as a limiting factor, biologically based reinforcement mechanisms are presumed to be operative in areas where species presumably evolved in sympatry. Signals of historical introgression were largely congruent with the routes of species dispersal previously inferred from mitogenome data. Overall, the ddRADseq dataset provided a robust phylogenetic reconstruction of the genus Thymallus including new insights into historical hybridization and introgression, opening up new questions concerning their evolutionary history.
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Affiliation(s)
- Giulia Secci-Petretto
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences, U. Porto - University of Porto, Portugal
| | - Gernot K Englmaier
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | - Steven J Weiss
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria.
| | - Alexander Antonov
- Institute of Water and Ecological Problems, Far East Branch, Russian Academy of Sciences, ul. Kim Yu Chena 65, Khabarovsk, 680063 Russia
| | - Henri Persat
- Société Française d'Ichthyologie, Muséum National d'Histoire Naturelle Paris, France, 57 rue Cuvier CP26, 75005 Paris, France
| | - Gael P J Denys
- Unité Patrimoine Naturel - Centre d'expertise et de données (2006 OFB - CNRS - MNHN), Muséum national d'Histoire naturelle, 36 rue Geoffroy Saint-Hilaire CP 41, 75005 Paris, France; Biologie des organismes et écosystèmes aquatiques (BOREA 8067), MNHN, CNRS, IRD, SU, UCN, UA, 57 rue Cuvier CP26, 75005 Paris, France
| | - Tamara Schenekar
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | | | - Eric B Taylor
- Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z, Canada
| | - Elsa Froufe
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal.
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4
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Rochat EC, Paterson RA, Blasco‐Costa I, Power M, Adams CE, Greer R, Knudsen R. Temporal stability of polymorphic Arctic charr parasite communities reflects sustained divergent trophic niches. Ecol Evol 2022; 12:e9460. [PMID: 36349257 PMCID: PMC9636502 DOI: 10.1002/ece3.9460] [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: 05/13/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 11/08/2022] Open
Abstract
Polymorphic Arctic charr Salvelinus alpinus populations frequently display distinct differences in habitat use, diet, and parasite communities. Changes to the relative species densities and composition of the wider fish community have the potential to alter the habitat niche of sympatric Arctic charr populations. This study evaluated the temporal stability of the parasite community, diet, and stable isotopes (δ13C, δ15N) of three sympatric Arctic charr morphs (piscivore, benthivore, and planktivore) from Loch Rannoch, Scotland, in relation to changes to the fish community. All Arctic charr morphs displayed distinct differences in parasite communities, diet, and stable isotope signatures over time, despite the establishment of four new trophically transmitted parasite taxa, and increased fish and zooplankton consumption by the piscivorous and planktivore morphs, respectively. Native parasite prevalence also increased in all Arctic charr morphs. Overall, Loch Rannoch polymorphic Arctic charr morph populations have maintained their distinct trophic niches and parasite communities through time despite changes in the fish community. This result indicates that re‐stocking a native fish species has the potential to induce shifts in the parasite community and diet of Arctic charr morphs.
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Affiliation(s)
- Eloïse C. Rochat
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
- Natural History Museum of Geneva Geneva Switzerland
| | | | - Isabel Blasco‐Costa
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
- Natural History Museum of Geneva Geneva Switzerland
| | - Michael Power
- Department of Biology University of Waterloo Waterloo Canada
| | - Colin E. Adams
- Scottish Centre for Ecology & the Natural Environment University of Glasgow Glasgow UK
| | | | - Rune Knudsen
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
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Grenier G, Smalås A, Kjær R, Knudsen R. Environmentally Modulated Repeat Evolution of Polymorphic Arctic Charr Life History Traits. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.771309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sympatric Arctic charr, Salvelinus alpinus (L. 1758), morphs have flexible but repeated life history strategies tested across five Norwegian lakes. In several Scandinavian polymorphic Arctic charr populations differentiated by their diet and habitat use, a large littoral omnivorous (LO) morph commonly cooccurs with a smaller profundal spawning (PB/PZ) morph. A third, large piscivorous (PP) morph is also known to occur within a portion of Arctic charr populations in the profundal habitat along with the PB/PZ individuals. Life history traits, such as age at maturity, growth, and diet are known to differ among coexisting morphs. Notably, the PP morph was the longest morph with the oldest age at maturity while the PB/PZ morph showed the shortest lengths overall and youngest age with LO morph being intermediate in both traits. Growth parameters differed across all the morphs. When examining growth within morph groups, the LO morph was found to have different growth across all lakes, while similar reproductive investments and different energy acquisition patterns were seen within the PB/PZ and PP morphs. These results suggest repeat evolution in several life history strategies of reproductively isolated Arctic charr sympatric morphs, notably for the first time in the PP morph, while also highlighting the importance of the local environment in modulating life history traits.
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6
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Klobucar SL, Rick JA, Mandeville EG, Wagner CE, Budy P. Investigating the morphological and genetic divergence of arctic char ( Salvelinus alpinus) populations in lakes of arctic Alaska. Ecol Evol 2021; 11:3040-3057. [PMID: 33841765 PMCID: PMC8019052 DOI: 10.1002/ece3.7211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/17/2020] [Accepted: 12/08/2020] [Indexed: 12/03/2022] Open
Abstract
Polymorphism facilitates coexistence of divergent morphs (e.g., phenotypes) of the same species by minimizing intraspecific competition, especially when resources are limiting. Arctic char (Salvelinus sp.) are a Holarctic fish often forming morphologically, and sometimes genetically, divergent morphs. In this study, we assessed the morphological and genetic diversity and divergence of 263 individuals from seven populations of arctic char with varying length-frequency distributions across two distinct groups of lakes in northern Alaska. Despite close geographic proximity, each lake group occurs on landscapes with different glacial ages and surface water connectivity, and thus was likely colonized by fishes at different times. Across lakes, a continuum of physical (e.g., lake area, maximum depth) and biological characteristics (e.g., primary productivity, fish density) exists, likely contributing to characteristics of present-day char populations. Although some lakes exhibit bimodal size distributions, using model-based clustering of morphometric traits corrected for allometry, we did not detect morphological differences within and across char populations. Genomic analyses using 15,934 SNPs obtained from genotyping by sequencing demonstrated differences among lake groups related to historical biogeography, but within lake groups and within individual lakes, genetic differentiation was not related to total body length. We used PERMANOVA to identify environmental and biological factors related to observed char size structure. Significant predictors included water transparency (i.e., a primary productivity proxy), char density (fish·ha-1), and lake group. Larger char occurred in lakes with greater primary production and lower char densities, suggesting less intraspecific competition and resource limitation. Thus, char populations in more productive and connected lakes may prove more stable to environmental changes, relative to food-limited and closed lakes, if lake productivity increases concomitantly. Our findings provide some of the first descriptions of genomic characteristics of char populations in arctic Alaska, and offer important consideration for the persistence of these populations for subsistence and conservation.
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Affiliation(s)
- Stephen L. Klobucar
- Department of Watershed Sciences and the Ecology CenterUtah State UniversityLoganUTUSA
- Present address:
Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAKUSA
| | - Jessica A. Rick
- Department of BotanyUniversity of WyomingLaramieWYUSA
- Program in EcologyUniversity of WyomingLaramieWYUSA
| | - Elizabeth G. Mandeville
- Department of BotanyUniversity of WyomingLaramieWYUSA
- Wyoming Cooperative Fish and Wildlife Research UnitDepartment of Zoology and PhysiologyUniversity of WyomingLaramieWYUSA
- Present address:
Department of Integrative BiologyUniversity of GuelphGuelphONCanada
| | - Catherine E. Wagner
- Department of BotanyUniversity of WyomingLaramieWYUSA
- Program in EcologyUniversity of WyomingLaramieWYUSA
| | - Phaedra Budy
- Department of Watershed Sciences and the Ecology CenterUtah State UniversityLoganUTUSA
- U.S. Geological SurveyUtah Cooperative Fish and Wildlife Research UnitLoganUTUSA
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7
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Chavarie L, Voelker S, Hansen MJ, Bronte CR, Muir AM, Zimmerman MS, Krueger CC. Temporal instability of lake charr phenotypes: Synchronicity of growth rates and morphology linked to environmental variables? Evol Appl 2021; 14:1159-1177. [PMID: 33897827 PMCID: PMC8061271 DOI: 10.1111/eva.13188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/24/2022] Open
Abstract
Pathways through which phenotypic variation among individuals arise can be complex. One assumption often made in relation to intraspecific diversity is that the stability or predictability of the environment will interact with expression of the underlying phenotypic variation. To address biological complexity below the species level, we investigated variability across years in morphology and annual growth increments between and within two sympatric lake charr Salvelinus namaycush ecotypes in Rush Lake, USA. A rapid phenotypic shift in body and head shape was found within a decade. The magnitude and direction of the observed phenotypic change were consistent in both ecotypes, which suggests similar pathways caused the variation over time. Over the same time period, annual growth increments declined for both lake charr ecotypes and corresponded with a consistent phenotypic shift of each ecotype. Despite ecotype-specific annual growth changes in response to winter conditions, the observed annual growth shift for both ecotypes was linked, to some degree, with variation in the environment. Particularly, a declining trend in regional cloud cover was associated with an increase of early-stage (ages 1-3) annual growth for lake charr of Rush Lake. Underlying mechanisms causing changes in growth rates and constrained morphological modulation are not fully understood. An improved knowledge of the biology hidden within the expression of phenotypic variation promises to clarify our understanding of temporal morphological diversity and instability.
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Affiliation(s)
- Louise Chavarie
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
- Beaty Biodiversity Research CenterUniversity of British ColumbiaVancouverBCCanada
- Scottish Centre for Ecology and the Natural EnvironmentIBAHCM, Rowardennan, Loch LomondGlasgowUK
| | - Steve Voelker
- SUNY College of Environmental Science and ForestrySyracuseNYUSA
| | | | - Charles R. Bronte
- U.S. Fish and Wildlife ServiceGreen Bay Fish and Wildlife Conservation OfficeNew FrankenWIUSA
| | | | | | - Charles C. Krueger
- Department of Fisheries and WildlifeCenter for Systems Integration and SustainabilityMichigan State UniversityEast LansingMIUSA
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8
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Davidsen JG, Power M, Knudsen R, Sjursen AD, Kjaerstad G, Rønning L, Arnekleiv JV. Marine trophic niche use and life history diversity among Arctic charr Salvelinus alpinus in southwestern Greenland. JOURNAL OF FISH BIOLOGY 2020; 96:681-692. [PMID: 31970772 DOI: 10.1111/jfb.14261] [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: 01/08/2020] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
Life history strategies and potential marine niche use of Arctic charr Salvelinus alpinus (n = 237, 84-652 mm, total body length, LT ) were determined during the ice-free season (2012) at three different watercourses in south-western Greenland. All Arctic charr were collected from freshwater habitats. Based on stable isotopes of δ34 S, the Arctic charr were categorized as either marine- or freshwater-dependent feeders. The use of time-integrated trophic tracers (stable isotopes of δ13 C, δ15 N, δ34 S) suggested that several trophic groups of Arctic charr operate alongside within each fjord system. The groups suggested were one group that specialized in the marine habitat, in addition to two freshwater resident morphs (small-sized resident and/or large-growing cannibalistic individuals). Stomach contents consisted entirely of freshwater and terrestrial prey (i.e., insects), indicating that marine-dependent feeders also fed in freshwater habitats after return from their marine migration. Growth and maturity patterns further supported variable life history strategies within each watercourse. The life history strategy patterns and marine trophic niche use were consistent across the watercourses along several hundred kilometres of coastline. This study represents the first ecological baseline for partially anadromous populations of Greenland Arctic charr.
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Affiliation(s)
- Jan G Davidsen
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Michael Power
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Rune Knudsen
- Department of Arctic and Marine Biology, The Arctic University of Norway, Tromsø, Norway
| | - Aslak D Sjursen
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gaute Kjaerstad
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lars Rønning
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jo V Arnekleiv
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
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9
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Arostegui MC, Quinn TP. Ontogenetic and ecotypic variation in the coloration and morphology of rainbow trout (Oncorhynchus mykiss) in a stream–lake system. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Alternative ecotypes of diverse animal taxa exhibit distinct, habitat-specific phenotypes. Rainbow trout (Oncorhynchus mykiss), a salmonid fish, exhibits stream-resident (fluvial), lake-migrant (adfluvial) and ocean-migrant (anadromous) ecotypes throughout its range. We investigated the coloration, and morphology associated with swimming performance of wild, native non-anadromous rainbow trout in connected stream and lake habitats of a south-west Alaskan watershed to assess if they exhibited phenotypic diversity consistent with the presence of alternative fluvial and adfluvial ecotypes. Colour differences among rainbow trout of different size classes and habitats (stream or lake) indicated ecotype-specific pathways, diverging at the same point in ontogeny and resulting in different terminal coloration patterns. Specifically, lake-caught fish exhibited distinct silvering of the body, whereas stream-caught fish displayed banded coloration when small and bronze colour when larger. The morphology of lake-caught rainbow trout also differed from that of stream-caught fish in features associated with swimming performance, and they exhibited both shared and unique morphological patterns compared to sympatric Salvelinus species in those habitats [Dolly Varden (S. malma) in streams, and Arctic char (S. alpinus) in the lake]. Greater morphological variation within stream- than lake-caught rainbow trout, and their limited overlap in morphology, suggested population-specific partial migration. This study highlights the intraspecific diversity of migratory behaviour and how conservation of particular phenotypes depends on managing both for genotypes and for habitats.
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Affiliation(s)
- M C Arostegui
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - T P Quinn
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
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10
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Padrós F, Knudsen R, Blasco-Costa I. Histopathological characterisation of retinal lesions associated to Diplostomum species (Platyhelminthes: Trematoda) infection in polymorphic Arctic charr Salvelinus alpinus. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2018; 7:68-74. [PMID: 29988817 PMCID: PMC6032039 DOI: 10.1016/j.ijppaw.2018.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/12/2018] [Accepted: 01/20/2018] [Indexed: 01/01/2023]
Abstract
The eye represents an immune privileged organ where parasites can escape host reactions. This study provides the first systematic evidence of the pathology associated with Diplostomum sp. infection in the eye retina of fish (i.e. Arctic charr). Histological sections showed that the trematodes caused mechanical disengagement between the retinal pigmentary epithelium and the neurosensory retina, with damaged cones and rods in the outer segment and epithelium reduced to a single layer of pigmentary cells. The metacercariae were “floating” in possibly fluid-filled vesicles together with several round cells, mostly located in the anterio-dorsal and anterio-ventral areas of the eye near the iris. The round cells may indicate internal retinal damage repair mechanisms, without connections to the general immune system. Metacercariae intestines contained pigmented cellular debris indicating that they feed on retinal epithelium. These retinal lesions may have similar vision effects as focal retinal detachment in vertebrates. Diplostomum metacercaria alters fish visual acuity but may in a lesser degree lead to a severe or total visual impairment because of repairing mechanisms. The pathology in the retina seems thereby to be dependent on fish size, age and dose. Histological description of the distribution of Diplostomum in the eye of Arctic charr Salvelinus alpinus. Metacercaria specifically located in spaces formed between the retinal pigmentary epithelium and the neurosensory retina. Lesions display closer similarities with those observed in retinal detachment in other species. Changes in the frequency and distribution of the lesions between morphs are suggested.
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Affiliation(s)
- F Padrós
- Fish Diseases Diagnostic Service, BAVE, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
| | - R Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Langnes, P.O. Box 6050, 9037 Tromsø, Norway
| | - I Blasco-Costa
- Natural History Museum of Geneva, PO Box 6434, CH-1211 Geneva 6, Switzerland
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11
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Simonsen MK, Siwertsson A, Adams CE, Amundsen PA, Præbel K, Knudsen R. Allometric trajectories of body and head morphology in three sympatric Arctic charr ( Salvelinus alpinus (L.)) morphs. Ecol Evol 2017; 7:7277-7289. [PMID: 28944016 PMCID: PMC5606865 DOI: 10.1002/ece3.3224] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 05/26/2017] [Accepted: 06/01/2017] [Indexed: 01/01/2023] Open
Abstract
A study of body and head development in three sympatric reproductively isolated Arctic charr (Salvelinus alpinus (L.)) morphs from a subarctic lake (Skogsfjordvatn, northern Norway) revealed allometric trajectories that resulted in morphological differences. The three morphs were ecologically assigned to a littoral omnivore, a profundal benthivore and a profundal piscivore, and this was confirmed by genetic analyses (microsatellites). Principal component analysis was used to identify the variables responsible for most of the morphological variation of the body and head shape. The littoral omnivore and the profundal piscivore morph had convergent allometric trajectories for the most important head shape variables, developing bigger mouths and relatively smaller eyes with increasing head size. The two profundal morphs shared common trajectories for the variables explaining most of the body and head shape variation, namely head size relative to body size, placement of the dorsal and pelvic fins, eye size and mouth size. In contrast, the littoral omnivore and the profundal benthivore morphs were not on common allometric trajectories for any of the examined variables. The findings suggest that different selective pressures could have been working on traits related to their trophic niche such as habitat and diet utilization of the three morphs, with the two profundal morphs experiencing almost identical environmental conditions.
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Affiliation(s)
- Marianne Knutsdotter Simonsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Anna Siwertsson
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Colin Ean Adams
- Scottish Centre for Ecology and the Natural Environment IBAHCM, University of Glasgow Glasgow UK
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Kim Præbel
- Faculty of Biosciences, Fisheries and Economics The Norwegian College of Fishery Science UiT The Arctic University of Norway Tromsø Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
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