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.

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.

Densities of juvenile brown trout (Salmo trutta) in two subarctic rivers: assessing the predictive capability of habitat preference indices

1999 ◽  
Vol 56 (8) ◽  
pp. 1420-1427 ◽  
Author(s):  
Aki Mäki-Petäys ◽  
Timo Muotka ◽  
Ari Huusko
Keyword(s):  
Brown Trout ◽  
Habitat Preference ◽  
Salmo Trutta ◽  
Winter Habitat ◽  
High Discharge ◽  
Site Variation ◽  
Brown Trout Salmo Trutta ◽  
Negative Effect ◽  
Juvenile Brown Trout ◽  
Survival Density

We examined the applicability of habitat preference indices for predicting density variations of age-0 brown trout (Salmo trutta) in two rivers in northern Finland. Trout densities in these rivers were monitored for 7 or 8 years. Habitat suitability for trout fry was assessed using summer and winter preference curves for water velocity, depth, and substrate. Substrate suitability indices based on summer preference curves explained 21-74% of the among-site variation in trout densities. The negative effect of high discharge on trout abundance was best predicted by the composite depth × substrate index. Sites with the highest "apparent survival" (density of age-1 trout in year t versus density of age-0 trout in year t - 1) produced high indices when winter substrate curves for age-0 trout were used, indicating high immigration rates to these sites. Our study shows that when preference indices are used for predictive purposes, the mechanisms underlying habitat "bottlenecks" must be known. In boreal areas, winter presents a bottleneck period for juvenile salmonids, and we stress the importance of using winter habitat curves when habitat hydraulic models are applied to areas with severe winter conditions.

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