scholarly journals Migration strategies of brown trout ( Salmo trutta ) in a subarctic river system as revealed by stable isotope analysis

2018 ◽  
Vol 28 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Timo J. Ruokonen ◽  
Mikko Kiljunen ◽  
Jaakko Erkinaro ◽  
Panu Orell ◽  
Olli Sivonen ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Brown Trout ◽  
Stable Isotope Analysis ◽  
Salmo Trutta ◽  
Isotope Analysis ◽  
River System ◽  
Brown Trout Salmo Trutta ◽  
Migration Strategies

Estimating the contribution of sympatric anadromous and freshwater resident brown trout to juvenile production

2004 ◽  
Vol 55 (2) ◽  
pp. 185 ◽  
Author(s):  
K. Charles ◽  
J.-M. Roussel ◽  
R. A. Cunjak
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Isotope Analysis ◽  
Nitrogen Stable Isotope ◽  
Carbon And Nitrogen ◽  
Relative Contribution ◽  
Brown Trout Salmo Trutta ◽  
Resident Female ◽  
Freshwater Resident

Carbon and nitrogen stable isotope analysis was used to study the reproductive contributions of anadromous and freshwater resident female brown trout (Salmo trutta L.) in La Roche Brook (Normandy, France), where both forms live in sympatry. Sixty-nine emerging fry were sampled by electrofishing in three different locations in the lower, middle and upper reaches of the stream, in March–April 2002. A collection of samples with known origin (brown trout eggs and fin tissues and benthic invertebrates) allowed classification of each emerging fry as the progeny of freshwater resident (δ13C = –26.0‰ ± 0.8 s.d.; δ15N = 12.5‰ ± 1.4 s.d.) or anadromous (δ13C = –18.8‰ ± 0.6 s.d., δ15N = 14.8‰ ± 0.9 s.d.) female brown trout. It was then possible to estimate the relative contribution (33%) of anadromous females to the population of fry that emerged from redds in 2002 and to evaluate the extent to which freshwater and anadromous spawning grounds overlapped in the stream.

Stable isotope niche convergence in coexisting native and non-native salmonids across age classes

2020 ◽  
Vol 77 (8) ◽  
pp. 1359-1365 ◽  
Author(s):  
Julien Cucherousset ◽  
Libor Závorka ◽  
Sergine Ponsard ◽  
Régis Céréghino ◽  
Frédéric Santoul
Keyword(s):  
Stable Isotope ◽  
Brown Trout ◽  
Brook Trout ◽  
Native Species ◽  
Salmo Trutta ◽  
Niche Overlap ◽  
Age Classes ◽  
Terrestrial Invertebrates ◽  
Brown Trout Salmo Trutta ◽  
Native Salmonids

Niche divergence resulting from coevolution is commonly believed to favour coexistence among competing species; however, recent investigations have demonstrated that an unexpected niche convergence can occur when native and non-native species coexist. Yet, our understanding of the ontogenetic characteristics of this niche convergence remains limited. In the present study, we quantified the stable isotope niche of native brown trout (Salmo trutta) in allopatry and sympatry with non-native brook trout (Salvelinus fontinalis) across four age classes. Our results demonstrated that brown trout displayed a stable isotope niche closer to brook trout in sympatry than in allopatry, which was likely driven by an increased consumption of terrestrial invertebrates by sympatric brown trout. Stable isotope niche overlap was the strongest for young-of-the-year individuals and the intensity of overlap between sympatric native brown trout and non-native brook trout decreased during ontogeny. These findings indicate that niche convergence between the species occur at the earliest age class of the native species and are maintained across ontogeny.

scholarly journals Food Web Analysis of Jordanelle Reservoir, Utah, USA: Where Do All the Rainbows Go?

2018 ◽  
Vol 11 (1) ◽  
pp. 27-35
Author(s):  
Joshua A. Verde ◽  
Mark C. Belk
Keyword(s):  
Rainbow Trout ◽  
Stable Isotope ◽  
Food Web ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Yellow Perch ◽  
Fish Community ◽  
Isotope Analysis ◽  
Smallmouth Bass ◽  
Food Web Structure

Background: Reservoir communities in the intermountain west are typically dominated by a mix of introduced fishes. Due to the non-coevolved interactions present in these communities, energy flow and trophic interactions may not facilitate optimal growth and survival for all species. It is difficult to predict how well each species will survive in such novel communities. One such community is in Jordanelle Reservoir in northern Utah, USA. Recently, low survival and recruitment of stocked rainbow trout (Onchorhynchus mykiss) have been observed in Jordanelle Reservoir. Objective: We characterize the food web structure of the fish community in Jordanelle reservoir to infer competitive or predatory interactions that might lead to a poor return of stocked rainbow trout. Methods: We performed a stable isotope analysis on the fish community in Jordanelle Reservoir and carried out niche space analyses using the software package Stable Isotope Bayesian Ellipse (SIBER) in R. Results: Small rainbow trout exhibit high competitive overlap with brown trout (Salmo trutta), smallmouth bass (Micropterus dolomieu), and yellow perch (Perca flavescens). In addition, large brown trout and large smallmouth bass may feed heavily on small rainbow trout. Conclusion: Food web analysis suggests that rainbow trout encounter a highly competitive and potentially high predation environment in Jordanelle reservoir, leading to observed low return rates.

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