The When, What and Where of Freshwater Feeding

Johansen, Mette Dencker; Erkinaro, Jaakko; Amundsen, Per‐Arne

doi:10.1002/9781444327755.ch4

Cited by 18 publications

(22 citation statements)

References 104 publications

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“…Atlantic salmon (Salmo salar) are opportunistic feeders both in freshwater and at sea. In freshwater, juvenile salmon utilize a variety of habitats requiring different feeding strategies for benthic, pelagic, or surface-drifting prey (Thonney and Gibson, 1989;Johansen et al, 2011), with seasonal differences in prey species utilization (Amundsen et al, 2001;Grader and Letcher, 2006), and habitat shifts to facilitate active feeding (Stradmeyer and Thorpe, 1987;Erkinaro et al, 1998). Protein and lipid levels vary among juveniles from different habitats, with resulting differences in overall growth and energy status (Cunjak, 1992;Erkinaro and Niemelä, 1995;Dempson et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Characterizing the trophic position and shift in Atlantic salmon (Salmo salar) from freshwater to marine life-cycle phases using stable isotopes

Dixon

Power

Dempson

et al. 2012

ICES Journal of Marine Science

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Dixon, H. J., Power, M., Dempson, J. B., Sheehan, T. F., and Chaput, G. 2012. Characterizing the trophic position shift in Atlantic salmon (Salmo salar) from freshwater to marine life-cycle phases using stable isotopes. – ICES Journal of Marine Science, 69: 1646–1655. Marine survival and recruitment of Atlantic salmon (Salmo salar) are commonly thought to be influenced by linkages between marine temperature and growth. Salmon are opportunistic feeders that are likely to be affected by the quality and quantity of prey available. During the marine phase, salmon often target larger zooplankton and fish, with a preference for fish over crustaceans. European salmon recruitment appears to be linked to forage abundance, which affects post-smolt growth critically during the first summer at sea, but similar linkages have not been shown for North American populations. Here, trophic differences within and among populations and life stages of Atlantic salmon during the freshwater and marine life-history phases are investigated. Stable isotope methods were used to characterize trophic dynamics by sampling smolts and returning adult survivors from rivers spanning a broad geographic range in Canada (southern Labrador to the Bay of Fundy), as well as non-maturing salmon sampled at West Greenland. Analyses indicate that salmon undergo a marked change in feeding as they migrate from freshwater and show the expected high reliance on pelagic foodwebs in the marine environment. Documented changes in ocean climate, pH, and the possibility of regime shifts are likely to have significant impacts on pelagic feeding fish, including Atlantic salmon. Due to the similar marine feeding ecology suggested here for adults from different age groups, these changes could have a widespread effect on multiple life-history stages of Atlantic salmon.

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Section: Introductionmentioning

confidence: 99%

Characterizing the trophic position and shift in Atlantic salmon (Salmo salar) from freshwater to marine life-cycle phases using stable isotopes

Dixon

Power

Dempson

et al. 2012

ICES Journal of Marine Science

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“…In general, seasonal transition in the diets of juvenile S. salar moves from Ephemeroptera, Diptera and Plecoptera in spring, to Ephemeroptera, Diptera (including Simuliidae) and terrestrial insects in summer. By autumn, Trichoptera larvae become dominant, while in winter the diet shifts to a combination of Plecoptera, Ephemeroptera and Trichoptera (Johansen et al ., ). The sampling of juvenile individuals from the Kapisillit River in both years occurred in the late Arctic summer.…”

Section: Discussionmentioning

confidence: 97%

“…The sampling of juvenile individuals from the Kapisillit River in both years occurred in the late Arctic summer. Our findings correspond well to the overall feeding preferences of juvenile S. salar found elsewhere (Johansen et al ., ) .…”

Section: Discussionmentioning

confidence: 97%

Demographic and genetic description of Greenland's only indigenous Atlantic salmon Salmo salar population

Arnekleiv

Davidsen

Sheehan

et al. 2019

Journal of Fish Biology

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A survey of the Kapisillit River system was conducted in 2005 and 2012 to study the only indigenous Atlantic salmon Salmo salar population in Greenland. Little is known about its characteristics or its relationship with other S. salar populations across the species range. Juvenile S. salar were captured in all stations surveyed within the lower river with the highest densities lower in the river and decreasing densities with increasing distance from the river mouth. Captured juveniles ranged from 0+ to 7+ years old and the predominant smolt age was between 4 and 6 years. Median length of 0+ and 1+ juveniles in August-September was 38.8 and 70.4 mm, respectively. The proportion of mature male parr increased from 4% for 1+ year old fish to 95% for fish greater than 2 years old. Genetic analysis using 96 single nucleotide polymorphisms (SNP) revealed a high degree of genetic similarity between collections, extremely low genetic diversity and low estimates of effective population size (N e = 28.7; 95% CI = 19.7-42.4).Genetic comparison to range-wide S. salar populations demonstrated that the Kapisillit River S. salar is an outgroup of the eastern Atlantic stock complex, which is consistent with the hypothesised colonisation from the east. River morphology and the absence of glacier runoff are hypothesised to be the main reasons for the relatively high river temperatures supporting this self-sustaining population of S. salar. Given its uniqueness and persistence, this population represents an important part of range-wide biodiversity of S. salar.

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“…Fishes have the ability to apportion energy to lipid stores to prepare for periods of scarce resources, such as in winter ( Mogensen and Post, 2012 ). Cooler water temperatures in the autumn and winter can reduce activity and feeding rates of fishes ( Burel et al , 1996 ; Johansen et al , 2011 ), which can minimize energy expenditures and allow for increased energy storage ( Morales et al , 2012 ). Silver carp have also been observed to situate themselves in positions of low water velocity to conserve energy ( Calkins et al , 2012 ).…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal influences on the physiological condition of invasive silver carp

Liss

Sass

Suski

2013

Conservation Physiology

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The When, What and Where of Freshwater Feeding

Cited by 18 publications

References 104 publications

Characterizing the trophic position and shift in Atlantic salmon (Salmo salar) from freshwater to marine life-cycle phases using stable isotopes

Characterizing the trophic position and shift in Atlantic salmon (Salmo salar) from freshwater to marine life-cycle phases using stable isotopes

Demographic and genetic description of Greenland's only indigenous Atlantic salmon Salmo salar population

Spatial and temporal influences on the physiological condition of invasive silver carp

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