Growth of Young Migratory Brown Trout Salmo trutta Correlated with Water Temperature in Norwegian Rivers

10.2307/4883 ◽  
1990 ◽  
Vol 59 (2) ◽  
pp. 603 ◽  
Author(s):  
Arne J. Jensen
Keyword(s):  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta

Unravelling the effects of water temperature and density dependence on the spatial variation of brown trout (Salmo trutta) body size

2012 ◽  
Vol 69 (5) ◽  
pp. 821-832 ◽  
Author(s):  
Irene Parra ◽  
Ana Almodóvar ◽  
Daniel Ayllón ◽  
Graciela G. Nicola ◽  
Benigno Elvira
Keyword(s):  
Body Size ◽  
Spatial Variation ◽  
Density Dependence ◽  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Maximum Growth ◽  
Suitable Habitat ◽  
Brown Trout Salmo Trutta ◽  
Potential Maximum

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.

scholarly journals Understanding inter-reach variation in brown trout (Salmo trutta) mortality rates using a hierarchical Bayesian state-space model

2017 ◽  
Vol 74 (10) ◽  
pp. 1612-1627 ◽  
Author(s):  
Victor Bret ◽  
Hervé Capra ◽  
Véronique Gouraud ◽  
Nicolas Lamouroux ◽  
Jérémy Piffady ◽  
...  
Keyword(s):  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Hierarchical Bayesian ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Animal Populations ◽  
Brown Trout Salmo Trutta ◽  
Shelter Availability ◽  
Dependent Mortality

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.

Longevity, Body Size, and Growth in Anadromous Brown Trout (Salmo trutta)

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 ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Ambient Water ◽  
Ambient Water Temperature ◽  
Brown Trout Salmo Trutta ◽  
Interpopulation Variation ◽  
Temperature And Growth

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.

scholarly journals Influence of discharge, hydraulics, water temperature, and dispersal on density synchrony in brown trout populations (Salmo trutta)

2016 ◽  
Vol 73 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Victor Bret ◽  
Benjamin Bergerot ◽  
Hervé Capra ◽  
Véronique Gouraud ◽  
Nicolas Lamouroux
Keyword(s):  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Age Groups ◽  
Negative Influence ◽  
Spawning Period ◽  
Emergence Period ◽  
Discharge Water ◽  
Brown Trout Salmo Trutta ◽  
Influence Of Substrate

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.

scholarly journals Brown trout (Salmo trutta) growth and condition along a winter thermal gradient in temperate streams

2017 ◽  
Vol 74 (1) ◽  
pp. 56-64 ◽  
Author(s):  
W.E. French ◽  
B. Vondracek ◽  
L.C. Ferrington ◽  
J.C. Finlay ◽  
D.J. Dieterman
Keyword(s):  
Water Temperature ◽  
Brown Trout ◽  
Thermal Regime ◽  
Salmo Trutta ◽  
Stream Water ◽  
Juvenile Fish ◽  
Late Winter ◽  
Caloric Density ◽  
Significant Difference ◽  
Brown Trout Salmo Trutta

Winter harshness and the degree to which it can impact stream-dwelling salmonid populations has received considerable attention from fisheries biologists, although some debate exists regarding the importance of winter severity for local populations. Groundwater input may buffer stream water temperature and benefit fish in buffered versus unbuffered streams. Overwinter growth and condition of individual brown trout were measured in 24 groundwater-dominated streams, and the relations between winter growth and condition to stream thermal regime (quantified by regressions of air and water temperature) and diet quality (amount and caloric density of prey) were examined in a subset of 16 streams. Brown trout (Salmo trutta) growth rate (mg·g−1·day−1) was positive overwinter in 18 of 24 streams, and there was no significant change in condition between early and late winter. Juvenile fish grew faster than adults, but there was no significant difference in condition between adults and juveniles. Thermal regime positively influenced winter growth for both adults and juveniles, likely mediated through moderation of water temperature by groundwater, whereas diet had no significant effect on growth.

Difficulties in Aging Atlantic Salmon (Salmo salar) and Brown Trout (Salmo trutta) from Cold Rivers Due to Lack of Scales as Yearlings

1982 ◽  
Vol 39 (2) ◽  
pp. 321-325 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Age Determination ◽  
Considerable Proportion ◽  
Degree Days ◽  
Atlantic Salmon Salmo Salar ◽  
Brown Trout Salmo Trutta

Scales in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) from two cold Norwegian rivers first appeared when the salmon were 33–34 mm long (total length) and the trout were 35–38 mm long. A considerable proportion of the yearlings did not form scales in years with a low water temperature (less than 1000–1100 degree-days from May to October); these individuals lacked the first annulus in the scales. Scales with five circuli or more seldom occurred. The number of days per year with a water temperature above 6.5 °C was better correlated to the formation of scales in Atlantic salmon than the degree-days. In years when the water temperature exceeded 6.5 °C for more than 70–80 days, only minor errors arose in age determination of the salmon; when the temperature exceeded 6.5 °C for less than 70–80 days, some individuals lacked the first annulus in their scales.Key words: Atlantic salmon, brown trout, age determination, temperature, scale formation

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