Capture–Recapture Experiment with Fly-Caught Brown (Salmo trutta) and Rainbow Trout (S. gairdneri)

1986 ◽  
Vol 43 (4) ◽  
pp. 896-899 ◽  
Author(s):  
L. D. Favro ◽  
P. K. Kuo ◽  
J. F. McDonald
Keyword(s):  
Rainbow Trout ◽  
Data Base ◽  
Brown Trout ◽  
Salmo Trutta ◽  
The Other ◽  
Capture Recapture ◽  
Capture Method

A data base on angler-captured brown (Salmo trutta) and rainbow trout (S. gairdneri) in the Au Sable River of Michigan is analyzed and compared with electrofishing data. The angling recapture frequency for brown trout increases rapidly with increasing length, while the recapture frequency for rainbow trout is independent of length. Anglers caught a greater number of fish over 33 cm long than did the electrofishers in the same water. The anglers and the electrofishers appear to have captured fish from different subpopulations; therefore, conclusions based on data obtained by one capture method may not be applicable to the other.

scholarly journals Higher mortality of the less suitable brown trout host compared to the principal Atlantic salmon host when infested with freshwater pearl mussel (Margaritifera margaritifera) glochidia

2021 ◽  
Author(s):  
Janhavi Marwaha ◽  
Per Johan Jakobsen ◽  
Sten Karlsson ◽  
Bjørn Mejdell Larsen ◽  
Sebastian Wacker
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Host Species ◽  
Salmo Trutta ◽  
The Other ◽  
Margaritifera Margaritifera ◽  
Pearl Mussel ◽  
Suitable Host ◽  
Freshwater Pearl Mussel ◽  
Host Interaction

AbstractThe freshwater pearl mussel (Margaritifera margaritifera) is a highly host-specific parasite, with an obligate parasitic stage on salmonid fish. Atlantic salmon (Salmo salar) and brown trout (Salmo trutta f. trutta and Salmo trutta f. fario) are the only hosts in their European distribution. Some M. margaritifera populations exclusively infest either Atlantic salmon or brown trout, while others infest both hosts with one salmonid species typically being the principal host and the other a less suitable host. Glochidial abundance, prevalence and growth are often used as parameters to measure host suitability, with the most suitable host species displaying the highest parameters. However, it is not known if the degree of host specialisation will negatively influence host fitness (virulence) among different host species. In this study we examined the hypothesis that glochidial infestation would result in differential virulence in two salmonid host species and that lower virulence would be observed on the most suitable host. Atlantic salmon and brown trout were infested with glochidia from two M. margaritifera populations that use Atlantic salmon as their principal host, and the difference in host mortality among infested and control (sham infested) fish was examined. Higher mortality was observed in infested brown trout (the less suitable host) groups, compared to the other test groups. Genetic assignment was used to identify offspring from individual mother mussels. We found that glochidia from individual mothers can infest both the salmonid hosts; however, some mothers displayed a bias towards either salmon or trout. We believe that the differences in host-dependent virulence and the host bias displayed by individual mothers were a result of genotype × genotype interactions between the glochidia and their hosts, indicating that there is an underlying genetic component for this parasite-host interaction.

scholarly journals State-dependent behavior and alternative behavioral strategies in brown trout (Salmo trutta L.) fry

2015 ◽  
Author(s):  
Joacim Näslund ◽  
Jörgen I Johnsson
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Population Based ◽  
Swimming Activity ◽  
The Other ◽  
Behavioral Strategies ◽  
Food Ration ◽  
State Dependent ◽  
Behavioral Trials ◽  
Bodily State

Animals generally adjust their behavior in response to bodily state (e.g. size and energy reserves) to optimize energy intake in relation to mortality risk, weighing predation probability against starvation. Here we investigated whether brown trout adjust their behavior in relation to feeding history (energetic status) and body size during a major early-life selection bottleneck, when fast growth also appear to be important. We manipulated growth using different food ration schemes over two consecutive time periods (P1 = 12 days, P2 = 23 days), excluding social effects through individual isolation. During these experimental periods the fish were fed either high or low food rations in a crossed design. In behavioral trials following the treatment, where acute hunger levels were standardized among all treatments, fish that were initially fed high rations (P1) and thereafter low rations (P2) had on average 15-21% higher swimming activity than the other groups, but large within-treatment variation rendered only weak statistical support for the effect. Furthermore, fish on low ration during P2 tended to be more aggressive than fish on high ration. Size was related to behavioral expression, with larger fish being more active and aggressive. Swimming activity and active aggression were positively correlated, forming a behavioral syndrome in the studied population. Based on these behavioral traits we could also distinguish two behavioral clusters, one consisting of more active and aggressive individuals, and the other consisting of less active and aggressive individuals. This indicates that two behavioral strategies may exist in young brown trout.

scholarly journals Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout (Oncorhynchus Mykiss) and Brown Trout (Salmo Trutta Morpha fario)

10.3791/56894 ◽  
2018 ◽  
Author(s):  
Radosław Kajetan Kowalski ◽  
Beata Sarosiek ◽  
Sylwia Judycka ◽  
Katarzyna Dryl ◽  
Joanna Grudniewska ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Salmonid Fish ◽  
Air Stripping
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