scholarly journals The Energetics of Feeding, Metabolism and Growth of Brown Trout (Salmo trutta L.) in Relation to Body Weight, Water Temperature and Ration Size

10.2307/3590 ◽  
1976 ◽  
Vol 45 (3) ◽  
pp. 923 ◽  
Author(s):  
J. M. Elliott
2011 ◽  
Vol 20 (4) ◽  
pp. 548-557 ◽  
Author(s):  
Linnea Lans ◽  
Larry A. Greenberg ◽  
Jens Karlsson ◽  
Olle Calles ◽  
Monika Schmitz ◽  
...  

1939 ◽  
Vol 16 (4) ◽  
pp. 446-473
Author(s):  
F. T. K. PENTELOW

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.


2012 ◽  
Vol 69 (5) ◽  
pp. 821-832 ◽  
Author(s):  
Irene Parra ◽  
Ana Almodóvar ◽  
Daniel Ayllón ◽  
Graciela G. Nicola ◽  
Benigno Elvira

This study looks at the relative influence of water temperature and density dependence on the spatial variation in body size of 126 brown trout ( Salmo trutta ) cohorts from 12 Iberian rivers over a 12-year period. Mean cohort mass and length of age groups 0+ to 2+ varied significantly among sampling sites because of the concurrent effect of water temperature and density dependence. Density in suitable habitat had a limiting role that influenced potential maximum growth of cohorts, and water temperature differentiated these cohorts in two groups of sites with high and low potential maximum growth. Water temperature had a positive cumulative effect on body size of all age classes. However, body size of age-0 trout was nonlinearly influenced by short-term exposure to extreme water temperature. Thus, extremely high temperatures became a limiting factor and had deleterious effects on growth. There were intracohort and intercohort effects of density dependence throughout the life span, which were mainly due to the density in the available suitable habitat of trout of the same age or older. The present study supports the hypothesis that both density-dependent and density-independent processes are crucial for the understanding of population dynamics and that their relative importance varies across scales of space and time.


2017 ◽  
Vol 74 (10) ◽  
pp. 1612-1627 ◽  
Author(s):  
Victor Bret ◽  
Hervé Capra ◽  
Véronique Gouraud ◽  
Nicolas Lamouroux ◽  
Jérémy Piffady ◽  
...  

Successful management and protection of wild animal populations relies on good understanding of their life cycles. Because population dynamics depends on intricate interactions of biological and ecological processes at various scales, new approaches are needed that account for the variability of demographic processes and associated parameters in a hierarchy of spatial scales. A hierarchical Bayesian model for the resident brown trout (Salmo trutta) life cycle was built to assess the relative influence of local and general determinants of mortality. The model was fitted to an extensive data set collected in 40 river reaches, combining abundance and environmental data (hydraulics, water temperature). Density-dependent mortality of juveniles increased at low water temperatures and decreased with shelter availability. High water temperature increased density-dependent mortality in adults. The model could help to predict monthly juvenile and adult mortality under scenarios of global warming and changes in shelter availability due to habitat degradation or restoration.


1991 ◽  
Vol 48 (10) ◽  
pp. 1838-1845 ◽  
Author(s):  
Bror Jonsson ◽  
Jan Henning L'Abée-Lund ◽  
Tor G. Heggberget ◽  
Arne J. Jensen ◽  
Bjørn O. Johnsen ◽  
...  

Longevity in 25 populations of anadromous brown trout (Salmo trutta) showed a significant trend with increasing life span at latitudes of 58–70°N in Norway, with the largest change from 58 to 60°N. Moreover, longevity was negatively correlated with temperature and growth rate in freshwater and at sea. Body size was negatively correlated with water temperature and growth rate in freshwater, but not with latitude or water temperature and growth rate at sea. Thus, conditions influencing development and metabolic rates in fresh water seem more important than conditions in the sea in determining variation in longevity and body size of anadromous brown trout. Our results support the hypothesis that interpopulation variation in longevity and body size is influenced by rate of metabolism, chiefly influenced by ambient water temperature.


2016 ◽  
Vol 73 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Victor Bret ◽  
Benjamin Bergerot ◽  
Hervé Capra ◽  
Véronique Gouraud ◽  
Nicolas Lamouroux

Environmental factors may cause synchronous density variations between populations. A better understanding of the processes underlying synchrony is fundamental to predicting resilience loss in metapopulations subject to environmental change. The present study investigated the determinants of synchrony in density time series of three age groups of resident brown trout (Salmo trutta) (0+, 1+, and adults) in 36 stream reaches. A series of Mantel tests were implemented to disentangle the relative effects on trout synchrony of geographical proximity, environmental synchrony in key environmental variables affecting trout dynamics (discharge, water temperature, hydraulics, and spawning substrate mobility), and density-dependent dispersal. Results indicated that environmental synchrony strongly explained trout synchrony over distances less than 75 km. This effect was partly due to a negative influence on 0+ trout of strong discharges during the emergence period and a more complex influence of substrate mobility during the spawning period. Dispersal between reaches had a weak influence on results. Juvenile and adult densities were strongly driven by survival processes and were not influenced by environmental synchrony. The results suggest that the environment can have general effects on population dynamics that may influence the resilience of metapopulations.


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