The influence of spawning habitat restoration on juvenile brown trout (Salmo trutta) density

2007 ◽  
Vol 64 (3) ◽  
pp. 509-515 ◽  
Author(s):  
Daniel Palm ◽  
Eva Brännäs ◽  
Fabio Lepori ◽  
Kjell Nilsson ◽  
Stefan Stridsman
Keyword(s):  
Brown Trout ◽  
Habitat Complexity ◽  
Salmo Trutta ◽  
Habitat Restoration ◽  
Size Composition ◽  
Spawning Habitat ◽  
Gravel Beds ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout

Between 1992 and 2003, we assessed the density of age-0+ brown trout (Salmo trutta) in a channelized stream in northern Sweden, which was restored using two different schemes. One section of the stream was restored by the addition of boulders and reconstruction of gravel beds (boulder + gravel section), whereas another section was restored through addition of boulders only (boulder-only section). In addition, we compared the substrate size composition of gravel beds and the egg-to-fry survival between the two stream sections, and we related the density of age-0+ brown trout to the area of reconstructed gravel beds. After the restoration, the density of age-0+ brown trout increased significantly in the boulder + gravel section and was positively correlated with the area of reconstructed gravel beds. By contrast, the density of age-0+ brown trout did not change in the boulder-only treatment. Egg-to-fry survival was significantly higher in the boulder + gravel section compared with the boulder-only section, probably because of the higher content of sand and fines in the gravel beds of the latter treatment. This study shows that the density of age-0+ brown trout was limited by the availability and quality of spawning substrate rather than by the structural habitat complexity.

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.

Testing a model of drift-feeding using three-dimensional videography of wild brown trout, Salmo trutta, in a New Zealand river

2003 ◽  
Vol 60 (12) ◽  
pp. 1462-1476 ◽  
Author(s):  
Nicholas F Hughes ◽  
John W Hayes ◽  
Karen A Shearer ◽  
Roger G Young
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Focal Point ◽  
Three Dimensional ◽  
Size Composition ◽  
Invertebrate Drift ◽  
Intake Rate ◽  
Drift Feeding ◽  
Foraging Area ◽  
Brown Trout Salmo Trutta

We tested the assumptions and predictions of a foraging model for drift-feeding fish. We used three-dimensional videography to describe the foraging behavior of brown trout, Salmo trutta, mapped water depth and velocity in their foraging area, sampled invertebrate drift to determine length class specific drift densities, and captured trout to determine the size composition of their diet. The model overestimated the fish's prey capture rate and gross energy intake rate by a factor of two. Most of this error resulted from the fact that prey detection probabilities within the fish's foraging area averaged only half the expected value. This was the result of a rapid decrease in capture probability with increasing lateral distance from the fish's focal point. Some of the model's assumptions were accurate: equations for predicting reaction distance and minimum prey size supported reliable predictions of the shape and size of the fish's foraging area and the size composition of the diet. Other assumptions were incorrect: fish detected prey within the predicted reaction volume, not on its upstream surface as expected, fish intercepted prey more slowly than the expected maximum sustainable swimming speed, and fish captured about two-thirds of their prey downstream of their focal point, rather than upstream.

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