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Pettitt-Wade H, Hussey NE, Gallagher CP, Lea EV, Orrell DL, Loseto LL. Contrasting intra-individual variation in size-based trophic and habitat shifts for two coastal Arctic fish species. Oecologia 2023:10.1007/s00442-023-05423-9. [PMID: 37488308 PMCID: PMC10386975 DOI: 10.1007/s00442-023-05423-9] [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: 02/27/2022] [Accepted: 07/09/2023] [Indexed: 07/26/2023]
Abstract
Within and among species variation in trophic and habitat shifts with body size can indicate the potential adaptive capacity of species to ecosystem change. In Arctic coastal ecosystems, which experience dramatic seasonal shifts and are undergoing rapid change, quantifying the trophic flexibility of coastal fishes with different migratory tactics has received limited attention. We examined the relationships among body length and condition (Fulton's K, phase angle from Bioelectrical Impedance Analysis) with trophic and habitat shifts (differences in δ15N and δ13C between blood tissues with different turnover rates) of two abundant and culturally important species, anadromous Arctic char (Salvelinus alpinus, n = 38) and sedentary Greenland cod (Gadus ogac, n = 65) during summer in coastal marine waters near Ulukhaktok, Northwest Territories, Canada. Habitat shifts (δ13C) increased with length (i.e., pelagic to benthic-littoral) and crossed-equilibrium (zero) at mid-sizes for both species. Seasonal trophic shifts (δ15N) were generally positive (i.e., increasing trophic level) for Arctic char and negative for Greenland cod. As hypothesised, intra-individual variation in size-based trophic shifts (δ15N-length residuals) increased with length for Arctic char. However, there were no trends with length in Greenland cod. Our findings highlight the importance of flexibility through ontogeny and mobility for Arctic char, whereas Greenland cod were generalist to localized prey and habitat across all sizes. The significant effect of body condition (phase angle) on size-based trophic shifts in Arctic char, and size-based habitat shifts in Greenland cod, highlight the potential trade-offs of contrasting life history strategies and capacity for ontogenetic niche plasticity.
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Affiliation(s)
- Harri Pettitt-Wade
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, R3T 2N6, Canada.
- Integrative Biology, University of Windsor, Windsor, ON, N9B 3P4, Canada.
| | - Nigel E Hussey
- Integrative Biology, University of Windsor, Windsor, ON, N9B 3P4, Canada
| | - Colin P Gallagher
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, R3T 2N6, Canada
| | - Ellen V Lea
- Fisheries and Oceans Canada, Inuvik, NT, X0E 0T0, Canada
| | - Danielle L Orrell
- Integrative Biology, University of Windsor, Windsor, ON, N9B 3P4, Canada
| | - Lisa L Loseto
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, R3T 2N6, Canada
- Environment and Geography, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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Brown-Vuillemin S, Tremblay R, Chabot D, Sirois P, Robert D. Feeding ecology of redfish (Sebastes sp.) inferred from the integrated use of fatty acid profiles as complementary dietary tracers to stomach content analysis. JOURNAL OF FISH BIOLOGY 2023; 102:1049-1066. [PMID: 36794305 DOI: 10.1111/jfb.15348] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 02/13/2023] [Indexed: 05/13/2023]
Abstract
In the northern Gulf of St. Lawrence (nGSL), redfish (Sebastes mentella and Sebastes fasciatus combined) are at record levels of abundance following the strong recruitment of three consecutive cohorts in 2011-2013 and have become by far the most abundant demersal fish in the region. Understanding redfish trophic relationships is essential for the effective management and conservation of species in the nGSL ecosystem. To date, description and quantification of redfish diet in the region have been restricted to conventional stomach content analysis (SCA). Using analysis of fatty acid (FA) profiles as complementary dietary tracers, the authors conducted multivariate analyses on 350 livers of redfish which were collected in combination with stomach contents during a bottom-trawl scientific survey in August 2017. The predator FA profiles were compared to those of eight different redfish prey types identified as dietary important with SCA. Results suggested similitude between SCA and FA results, with zooplankton prey being more related to small (<20 cm) and medium (20-30 cm) redfish (16:1n7, 20:1n?, 22:1n9 and 20:5n3) than large (≥30 cm) ones, whereas shrimp prey seemed more related to large redfish size classes (18:2n6 and 22:6n3) relative to the small and medium ones. Although the SCA offers a glimpse in the diet only based on the most recently consumed prey, analysis of FA profiles provides a mid-term view indicating pelagic zooplankton consumption on calanoid copepod and confirming high predation pressure on shrimp. This study constitutes the first attempt of combining FA with SCA to assess the diet of redfish, highlights the benefits of FA as a qualitative tool and suggests improvements for future studies.
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Affiliation(s)
- Sarah Brown-Vuillemin
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Quebec, Canada
| | - Réjean Tremblay
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Quebec, Canada
| | - Denis Chabot
- Institut Maurice-Lamontagne, Pêches et Océans Canada, Mont-Joli, Quebec, Canada
| | - Pascal Sirois
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Dominique Robert
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Quebec, Canada
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Broad feeding niches of capelin and sand lance may overlap those of polar cod and other native fish in the eastern Canadian Arctic. Polar Biol 2020. [DOI: 10.1007/s00300-020-02738-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ontogenetic patterns in lipid and fatty acid biomarkers of juvenile polar cod (Boreogadus saida) and saffron cod (Eleginus gracilis) from across the Alaska Arctic. Polar Biol 2020. [DOI: 10.1007/s00300-020-02648-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Regional and temporal variation in fatty acid profiles of polar cod (Boreogadus saida) in Alaska. Polar Biol 2018. [DOI: 10.1007/s00300-018-2386-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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