Seasonal and spatial variation in the diet of brown trout (Salmo trutta L.) in the subarctic River Laxá, north-east Iceland

Gíslason, Gísli Már; Steingrímsson, Stefán Ó.

doi:10.1023/b:aeco.0000032052.04874.fb

Cited by 11 publications

(4 citation statements)

References 22 publications

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“…However, Pender & Kwak (2002) identified a positive selection for chironomids among age-0 trout, contrary to our data (brown trout <200 mm). Simulium is the dominant prey item of brown trout in subarctic streams in Iceland (Gislason & Steingrimsson 2004). …”

Section: Prey Utilisation Versus Available Benthosmentioning

confidence: 99%

Spatial and temporal variation in prey selection of brown trout in a cold Arkansas tailwater

Johnson

Coghlan

Harmon

2007

Ecology of Freshwater Fish

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– We examined prey utilisation patterns of brown trout (Salmo trutta Linnaeus) as related to available benthos in a cold tailwater (Little Red River, Arkansas) having low biodiversity of benthic macroinvertebrates and low availability of fish as prey. Benthic macroinvertebrates were sampled monthly in upstream and downstream sites over a 1‐year period. Stomach content analysis was also performed on 30 brown trout (10 each of three size classes) collected monthly from each site. Benthic and diet diversities were low at both sites, as isopods (Lirceus) accounted for 67% and 51% of the numerical abundance upstream and downstream, respectively, and 80% and 70% of all prey consumed by upstream and downstream brown trout. Physid snails (upstream) and chironomid larvae (downstream) accounted for most of the remaining prey taxa consumed. Piscivory and consumption of terrestrial invertebrates were rare. There was no clear relation between diet diversity and trout size. Densities of benthic macroinvertebrates and prey consumption were significantly greater upstream than downstream. Benthic macroinvertebrate assemblages and prey consumption were seasonally constant at both sites. Generally, prey consumption was consistent with availability of each prey in the benthos; the lack of benthic diversity and overwhelming abundance of one taxon (Lirceus) most likely contributed to food selection patterns. Although isopods are abundant within this tailwater to serve as a forage base, the displacement of native fish fauna because of the thermal regime of hypolimnetic release from Greers Ferry Reservoir probably serves as a major limitation to brown trout growth.

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Section: Prey Utilisation Versus Available Benthosmentioning

confidence: 99%

Spatial and temporal variation in prey selection of brown trout in a cold Arkansas tailwater

Johnson

Coghlan

Harmon

2007

Ecology of Freshwater Fish

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“…During the freshwater period the smolt feeds mostly on invertebrates (13). This results in a 100-200-fold weight gain over a period of approximately 2 years.…”

Section: Introductionmentioning

confidence: 99%

Body Burdens of Persistent Halogenated Compounds during Different Development Stages of Anadromous Brown Trout (Salmo trutta)

Svendsen

Vorkamp

Frederiksen

et al. 2007

Environ. Sci. Technol.

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Polychlorinated biphenyls (PCBs), DDTs, and polybrominated diphenyl ethers (PBDEs) were followed through the five life stages of a wild population of anadromous brown trout and related to variations in lipid content and exposure situations. Anadromous brown trout exhibits great variations in lipid content during its life cycle in the freshwater and marine environments. The results indicated substantial differences in PBDE and organochlorine exposure, with apparently more recent sources of PBDEs in the freshwater environment relative to the marine environment. Lipid and contaminant transfer were not always identical: The concentrations of PCBs, DDTs, and PBDEs (ng/g lipid weight) were about 15 times lower in the eggs compared to the muscle of their mother (e.g., 823 ng PCB/g Iw vs. 12,565 ng PCB/g lw, respectively). During the starving period from maiden to spawning trout the contaminant load increased by a higher factor than the lipid use. The data suggest a decoupling between lipid content and organohalogen concentrations for anadromous brown trout, which may contribute positively to reduce any potential negative effects of the transferred contaminants on eggs and fry.

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“…Diet specialization of juvenile fish can be due to experience and learning, whereas diet generalization may be caused by hunger (Andreassen et al, 2001). Therefore, the juvenile with similar productivity levels, was found to mostly eat benthic invertebrates, which included mainly blackfly larvae, chironomids, and freshwater snails (Gíslason & Steingrímsson, 2004). River management focusing on river primary productivity, such as those increasing algal production, altering habitat to promote the growth of algae, and using large woody debris, are possible options in creating a sustainable food source for the main macroinvertebrate prey items of juvenile S. salar (Thompson et al, 2018;Wootton, 2012).…”

Section: Dietary Niche Overlapmentioning

confidence: 99%

The prey availability and diet of juvenile Atlantic salmon (Salmo salar L.) in low‐productivity rivers in northern Europe

Lai,

Pálsson,

Guðbergsson

et al. 2024

Journal of Fish Biology

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The availability of resources varies across a species distributional range, and a low‐productivity area can make a species more vulnerable. We investigated the invertebrate composition and prey choice of juvenile Atlantic salmon (Salmo salar L.) in low‐productivity rivers in northeast Iceland, which is one of the species’ most northerly distributions. By sampling benthic and drift invertebrate populations, we found that prey availability was similar within and between rivers. Gut content samples showed that the main prey choice for juvenile S. salar was the Chironomidae. The type of food items consumed varied across different weight groups of S. salar, with smaller juveniles having more diverse diet. S. salar did not have a selection preference for chironomids, which indicates that they were eating the highly available prey in their environment, rather than hunting high biomass items such as terrestrial invertebrates and large Dipterans. Estimates of dietary niche showed that S. salar in these low‐productivity rivers relied on consuming what was most readily available, the chironomids, and that they must share resources with other salmonid species. This may be due to the low diversity of freshwater invertebrates (fewer prey options), whereas S. salar in nutrient‐rich rivers could rely more on terrestrial invertebrates as an additional subsidy in their diet. In conclusion, with limited prey choices, juvenile S. salar in nutrient‐poor rivers, especially in a biogeographically isolated region with low species diversity, may increase in vulnerability and decrease in adaptability to environmental change. Management methods that increase benthic prey abundance and diversity are recommended for conserving the S. salar population in a nutrient‐poor river.

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Seasonal and spatial variation in the diet of brown trout (Salmo trutta L.) in the subarctic River Laxá, north-east Iceland

Cited by 11 publications

References 22 publications

Spatial and temporal variation in prey selection of brown trout in a cold Arkansas tailwater

Spatial and temporal variation in prey selection of brown trout in a cold Arkansas tailwater

Body Burdens of Persistent Halogenated Compounds during Different Development Stages of Anadromous Brown Trout (Salmo trutta)

The prey availability and diet of juvenile Atlantic salmon (Salmo salar L.) in low‐productivity rivers in northern Europe

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