scholarly journals Individual differences in dominance-related traits drive dispersal and settlement in hatchery-reared juvenile brown trout

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jorge R. Sánchez-González ◽  
Alfredo G. Nicieza
Keyword(s):  
Body Size ◽  
Brown Trout ◽  
Environmental Conditions ◽  
Salmo Trutta ◽  
Spatial Scales ◽  
Juvenile Fish ◽  
Structured Populations ◽  
Dispersal Ability ◽  
Introduced Fish ◽  
Juvenile Brown Trout

AbstractEffective management of exploited populations is based on an understanding of population dynamics and evolutionary processes. In spatially structured populations, dispersal is a central process that ultimately can affect population growth and viability. It can be influenced by environmental conditions, individual phenotypes, and stochastic factors. However, we have a limited knowledge of the relative contribution of these components and its interactions, and which traits can be used as reliable predictors of the dispersal ability. Here, we conducted a longitudinal field experiment aimed to identify traits which can be used as proxy for dispersal in juvenile brown trout (Salmo trutta L.). We measured body size and standard metabolic rates, and estimated body shapes for 212 hatchery-reared juvenile fish that were marked with individual codes and released in a small coastal stream in northwest Spain. We registered fish positions and distances to the releasing point after 19, 41, 60 and 158 days in the stream. We detected a high autocorrelation of dispersal distances, demonstrating that most individuals settle down relatively soon and then hold stable positions over the study period. Body size and fish shape were reliable predictors of dispersal, with bigger and more robust-set individuals being more likely to settle closer to the release site than smaller and more elongated fish. In addition, the analysis of spacing and spatial patterns indicated that the dispersal of introduced fish could affect the distribution of resident conspecifics. All together, these results suggest that stocking programs aimed to the enhancement of overexploited populations at fine spatial scales can be optimized by adjusting the size and shape of the introduced fish to specific management targets and environmental conditions.

Competition among juvenile brown trout, grayling and landlocked Atlantic salmon in flumes - predicting effects of interspecific interactions on salmon reintroduction success

2020 ◽  
Author(s):  
Anna Hagelin ◽  
Eva Bergman
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Interspecific Interactions ◽  
Juvenile Fish ◽  
Active Species ◽  
Major Interest ◽  
Brown Trout Salmo Trutta ◽  
Riverine Habitats ◽  
Juvenile Brown Trout

Abstract Worldwide declines in salmonid populations have generated major interest in conservation and restoration of wild populations and riverine habitats. Species reintroductions to previous habitats raises questions about their potential impact on these systems. In River Klarälven, landlocked Atlantic salmon (Salmo salar) has been extinct from upper reaches for over 50 years due to hydropower dams. Here we study competitive interactions between salmon, grayling (Thymallus thymallus) and brown trout (Salmo trutta), that occur in the upper reaches of the river. We examine foraging rates, aggression and activity of juvenile fish in allopatry at three different densities and in sympatry with one or both potential competitors in laboratory flumes. Salmon captured prey less frequently in the presence of brown trout and grayling, whereas grayling and brown trout were unaffected by salmon, but affected each other. Grayling was the most aggressive and active species whereas salmon the least. Consequently, re-introduction of salmon probably will have little impact on grayling and brown trout, whereas grayling and brown trout could affect the success of re-introducing salmon.

scholarly journals Survival and growth rates of juvenile salmonids reared in lowland streams

2016 ◽  
Vol 24 (4) ◽  
pp. 187-200
Author(s):  
Janusz Golski ◽  
Jan Mazurkiewicz ◽  
Wojciech Andrzejewski ◽  
Antoni Przybył ◽  
Jerzy Kozak
Keyword(s):  
Body Weight ◽  
Brown Trout ◽  
Environmental Conditions ◽  
Salmo Trutta ◽  
Juvenile Fish ◽  
Stocking Density ◽  
Biological Parameters ◽  
Lowland Streams ◽  
Sea Trout ◽  
The Impact

Abstract The aim of this study was to assess the efficiency of propagating juvenile trout, Salmo trutta L. in small lowland streams and to evaluate the impact of the environmental conditions in the streams on the juvenile fish. Brown trout (Salmo trutta fario) and sea trout (Salmo trutta trutta) early fry fed under controlled conditions were used to stock third-order lowland streams. During summer, fall, and spring catches, fry were counted, measured, and weighed. The following parameters were calculated using the data collected: fry stocking density (ind. m-2); survival; specific mortality rate (SMR); length range; mean specimen length; body weight; mean body weight; specific growth rate (SGR); body condition (Fulton’s index). The ichthyological studies were accompanied by simultaneous analyses of environmental conditions that were performed monthly, and benthic macroinvertebrates were sampled in spring and fall. No differences were observed in the biological parameters analyzed between sea trout and brown trout. Variability in environmental parameters such as temperature, oxygenation, conductivity, and stream width and depth were associated with differentiation in the biological parameters of the fry. The results clearly indicate that the considerable potential of small lowland streams for the propagation of salmonid juvenile stages is currently underexploited.

Unidirectional Natural Hybridization between Brown Trout (Salmo trutta) and Atlantic Salmon (S. salar) in Newfoundland

1992 ◽  
Vol 49 (9) ◽  
pp. 1953-1958 ◽  
Author(s):  
Colin McGowan ◽  
William S. Davidson
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Dna Analysis ◽  
Juvenile Fish ◽  
Natural Hybridization ◽  
Major Influence ◽  
Isolating Mechanisms ◽  
Brown Trout Salmo Trutta ◽  
Sexually Mature

Protein electrophoresis and mitochondrial DNA analysis were used to detect the frequency and direction of natural hybridization between brown trout (Salmo trutta) and Atlantic salmon (S. salar) in nine Newfoundland rivers. In total, 37 hybrids were discovered in a sample of 792 juvenile fish for a regional frequency of 4.67%. Local frequencies ranged from 0.00 to 18.75% and were significantly heterogeneous. All of the hybrids sampled were produced from matings between female brown trout and male Atlantic salmon. Possible reasons for the breakdown of prereproductive isolating mechanisms between these species are considered. Reproductive characteristics of the populations involved appear to have a major influence on the dynamics of hybridization between these species in Newfoundland. It is proposed that an abundance of sexually mature Atlantic salmon parr in Newfoundland streams is responsible for both the frequency and direction of hybridization observed in this study.

scholarly journals Polystyrene microplastics do not affect juvenile brown trout (Salmo trutta f. fario) or modulate effects of the pesticide methiocarb

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Hannah Schmieg ◽  
Sven Huppertsberg ◽  
Thomas P. Knepper ◽  
Stefanie Krais ◽  
Katharina Reitter ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout

scholarly journals Investigating the phenology of seaward migration of juvenile brown trout (Salmo trutta) in two European populations

Hydrobiologia ◽  
2016 ◽  
Vol 775 (1) ◽  
pp. 139-151 ◽  
Author(s):  
E. R. Winter ◽  
J. S. Tummers ◽  
K. Aarestrup ◽  
H. Baktoft ◽  
M. C. Lucas
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Seaward Migration ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout ◽  
European Populations

Influence of food abundance on individual behaviour strategy and growth rate in juvenile brown trout (Salmo trutta)

2003 ◽  
Vol 81 (4) ◽  
pp. 684-692 ◽  
Author(s):  
Eva Brännäs ◽  
Sara Jonsson ◽  
Hans Lundqvist
Keyword(s):  
Brown Trout ◽  
Growth Rates ◽  
Salmo Trutta ◽  
Swimming Activity ◽  
Food Abundance ◽  
Individual Growth ◽  
Food Level ◽  
General Tendency ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout

We studied the benefit of being territorial as an effect of food abundance by measuring the proportions of individuals that displayed a territorial, floating (individuals occasionally displayed territorial behaviour), or nonterritorial (shoaling) behaviour strategy, and individual growth rates. Also, swimming activity was monitored as an indicator of emigration. Replicate groups of 12 juvenile brown trout (Salmo trutta) were released into an artificial stream channel, fed according to one of four food regimes for 10 days, and allocated to one of three behaviour categories. There was no significant relationship between food abundance and the number of territorial individuals. Instead, the proportions of individuals that displayed the alternative behaviour strategies, i.e., floating and nonterritorial, changed with food abundance. At the lowest food level, more individuals displayed nonterritorial than floating behaviour, but these two strategies were equally represented at the highest food level. The difference in growth rates with respect to behaviour category was highest at intermediate food levels. At the highest and lowest food levels, nonterritorial fish and floaters grew nearly as fast or as poorly, respectively, as the territorial individuals. Swimming activity between the two sections of the stream tank was greatest at the lowest food level, and there was a general tendency (not significant) for the floaters to exhibit the greatest activity.

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