Growth and Early Maturation of Brown Trout Salmo trutta in the Alatsoya River (Republic of Karelia)

Pavlov, E. D.; Bush, A. G.; Kostin, V. V.; Павлов, Д. С.

doi:10.1134/s1995082920060115

Cited by 5 publications

(1 citation statement)

References 20 publications

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“…At the same time, it seems likely that smaller (more vulnerable) males may be selected to delay migration (until autumn or the following year), or become residents, and instead mature early as precocious parr, because in so doing, they can minimise predation risks and exploit female mimicry or sneak mating to achieve fertilisation (Esteve, 2005;Garcia-Vazquez et al, 2001;Sloat et al, 2014). In other systems, precocious parr have been documented in brown trout from 1 year of age (Dȩbowski & Dobosz, 2017;Pavlov et al, 2020), suggesting this is a potentially relevant consideration across the range of males tagged in this study.…”

Section: Discussionmentioning

confidence: 99%

Sex‐ and length‐dependent variation in migratory propensity in brown trout

Lavender,

Hunziker,

McLennan

et al. 2023

Ecology of Freshwater Fish

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In partially migratory species, individuals either migrate at some point(s) in life or reside within their natal habitat throughout life. For salmonid fish, migration creates opportunities for feeding and growth, but it is also associated with increased mortality risk. Such trade‐offs likely differ between the sexes, since reproductive output is more closely tied to body size in females than males. However, testing hypotheses on sex‐specific migratory behaviour in would‐be first‐time migratory salmonids is difficult, since sexes are generally morphologically indistinguishable prior to maturation. Previous studies have evaluated the influence of sex on migration based on dissection of migratory juveniles or the sex ratio of returning adults. However, both approaches are potentially biased by differential survival during migration. Here, we utilise advances in minimally invasive genetic sex‐determination methods for salmonids to investigate sex‐specific, spring out‐migration propensity in potamodromous brown trout (Salmo trutta) in a pre‐Alpine, central European lake. We show that there are marked differences in migratory behaviour between males and females, with small (~10 cm) females being approximately twice as likely to migrate out of their natal river in spring compared to similarly sized males, which generally migrate for the first time at larger sizes (in similar proportions to larger females). This study highlights how novel genetic sex‐determination techniques can provide insight into the sex‐ and size‐specific life‐history trade‐offs that shape migration propensity. Moving forward, these techniques should become useful tools for ecologists and fisheries managers.

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Section: Discussionmentioning

confidence: 99%

Sex‐ and length‐dependent variation in migratory propensity in brown trout

Lavender,

Hunziker,

McLennan

et al. 2023

Ecology of Freshwater Fish

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Seasonal trophic niche width and overlap of mottled sculpin and brown trout in a regulated high‐elevation river

Platis,

Kanno,

Johnson

et al. 2024

Ecology of Freshwater Fish

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In temperate ecosystems, resource availability fluctuates seasonally due to changes in environmental conditions and productivity. Intra‐ and inter‐specific trophic niche overlap under resource limitation is a measure of competitive interactions and influences species coexistence and community dynamics, but patterns of this overlap are influenced by anthropogenic activities. To investigate seasonal trophic niche dynamics of coexisting fish species in a flow‐altered river, we analysed prey resources, stomach content samples and stable isotope signatures of mottled sculpin Cottus bairdii and juvenile brown trout Salmo trutta in the Blue River, Colorado, USA, a high‐elevation oligotrophic river. Prey biomass (i.e. benthic macroinvertebrates) peaked in spring and declined through summer and autumn. Stomach content and stable isotope analysis results showed that diet composition of mottled sculpin and brown trout varied seasonally in response to changes in prey availability. Stomach content analysis results revealed that in autumn, both species exhibited the highest frequency of empty stomachs and expanded population trophic niches due to increased inter‐individual diet variation despite decreased individual trophic niche breadth. Inter‐specific trophic niche overlap was relatively high across all seasons, but the lowest degree of overlap occurred in autumn of both years when prey availability was lowest. Isotopic analysis revealed similar trends to stomach content analysis, of wider isotopic niches and reduced overlap in autumn compared to spring. Our data indicated that seasonal variation affected individual‐ and population‐level trophic niche dynamics and inter‐specific niche overlap between mottled sculpin and brown trout. This trophic segregation under resource limitation may serve as a mechanism that facilitates species coexistence in a flow‐regulated, oligotrophic river.

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