Laboratory experiment on survival, growth and tag retention following PIT injection into the body cavity of juvenile brown trout (Salmo trutta)

1. The growth of brown trout (Salmo trutta), fed on Gammarus pulex, in their first and second years has been studied. 2. The growth in weight varies considerably from week to week but, generally speaking, it increases with increasing size of the fish. It is assumed that in these experiments the second point of inflection of the normal S-shaped growth curve was not reached because the fish were too young. 3. In all the fishes studied there was a period of slow growth during the winter and during the summer. Growth is at its maximum at temperatures between 50 and 60° F. 4. By careful adjustment of the rations it was possible to keep the body weight of the fish approximately constant from week to week. The amount of food required for this purpose varied from 51 to 270 mg./g. of body weight per week, but was mainly between 70 and 102 mg. and was apparently affected by the water temperature, being higher when the water was warmer. 5. Starved fish lost more weight at higher temperatures than at lower, but the loss of weight could not be related to the amount of food required to maintain the body weight constant at a given temperature. 6. The appetite of fully fed fish increases as the temperature rises to 60° F. but generally declines at temperatures higher than this. Between 40 and 50° F. the amount of growth made is roughly directly proportional to the amount of food eaten, but above 50° no such simple relation exists. 7. G. pulex is a very efficient food for trout; generally speaking about 5 g. of this food produce 1 g. increase in weight. If from this amount the quantity required to maintain the body weight constant is subtracted, it is found that 1 g. increase in weight is produced by about 3 g. of food available for growth. 8. The average weight of the Gammarus used as food in this experiment was 0.026 g., and it is estimated that for every gram increase of weight each fish consumed between 200 and 300 Gammarus.

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

Environmental Sciences Europe ◽

10.1186/s12302-020-00327-4 ◽

2020 ◽

Vol 32 (1) ◽

Cited By ~ 3

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

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

Hydrobiologia ◽

10.1007/s10750-016-2720-z ◽

2016 ◽

Vol 775 (1) ◽

pp. 139-151 ◽

Cited By ~ 20

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

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

Canadian Journal of Zoology ◽

10.1139/z03-047 ◽

2003 ◽

Vol 81 (4) ◽

pp. 684-692 ◽

Cited By ~ 19

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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Genetic variation of body size, condition and pyloric caeca number in juvenile brown trout, Salmo trutta L.

Aquaculture Research ◽

10.1111/j.1365-2109.2006.01474.x ◽

2006 ◽

Vol 37 (6) ◽

pp. 637-642 ◽

Cited By ~ 11

Author(s):

Jean M Blanc ◽

Huguette Poisson

Keyword(s):

Genetic Variation ◽

Body Size ◽

Brown Trout ◽

Salmo Trutta ◽

Pyloric Caeca ◽

Brown Trout Salmo Trutta ◽

Size Condition ◽

Juvenile Brown Trout

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0155 ◽

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.

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