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.

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 Assessing the suitable habitat for reintroduction of brown trout (Salmo trutta forma fario ) in a lowland river: A modeling approach

2018 ◽  
Vol 8 (10) ◽  
pp. 5191-5205
Author(s):  
Pieter Boets ◽  
Sacha Gobeyn ◽  
Alain Dillen ◽  
Eddy Poelman ◽  
Peter L. M. Goethals
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Suitable Habitat ◽  
Lowland River ◽  
Modeling Approach ◽  
Brown Trout Salmo Trutta

scholarly journals The response of a brown trout (Salmo trutta) population to reintroduced Eurasian beaver (Castor fiber) habitat modification

2021 ◽  
pp. 1-11
Author(s):  
Robert J. Needham ◽  
Martin Gaywood ◽  
Angus Tree ◽  
Nick Sotherton ◽  
Dylan Roberts ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Low Cost ◽  
Fork Length ◽  
Freshwater Ecosystems ◽  
Habitat Modification ◽  
Castor Fiber ◽  
Suitable Habitat ◽  
Eurasian Beaver ◽  
Brown Trout Salmo Trutta

Globally, freshwaters are the most degraded and threatened of all ecosystems. In northern temperate regions, beaver (Castor spp.) reintroductions are increasingly used as a low-cost and self-sustaining means to restore river corridors. River modifications by beavers can increase availability of suitable habitat for fish, including salmonids. This study investigated the response of a population of brown trout (Salmo trutta) to reintroduced Eurasian beaver (Castor fiber) habitat modifications in northern Scotland. The field site comprised two streams entering a common loch; one modified by beavers, the other unaltered. Electrofishing and PIT telemetry surveys indicated abundance of post-young-of-the-year (post-YOY) trout was higher in the modified stream. Considering juvenile year groups (YOY and post-YOY) combined, abundance and density varied with year and season. In the modified stream, fork length and mass were greater, there was a greater variety of age classes, and mean growth was positive during all seasons. Beavers had profound effects on the local brown trout population that promoted higher abundances of larger size classes. This study provides important insight into the possible future effect of beavers on freshwater ecosystems.

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.

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 Life History Tactics in Cohorts of a Partial Migratory Brown Trout (Salmo trutta L.) Population

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ivan C. Olsson ◽  
Larry A. Greenberg
Keyword(s):  
Body Size ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Female Fecundity ◽  
Trout Population ◽  
Delayed Reproduction ◽  
Brown Trout Salmo Trutta ◽  
Downstream Section ◽  
And Migration ◽  
Brown Trout Population

We monitored temporal changes in body size for three cohorts of a partial migratory, lake-migrating brown trout population. We tested if body mass differed between nonmigratory males, migrants, and other members of the cohort (females and immature males). We hypothesized that large-sized individuals would mature as nonmigratory males or migrate at younger ages than small-sized individuals. As previous studies have shown that female fecundity is influenced by body size and that more trout from the downstream section (D) of the stream migrated than from the upstream section (U), we hypothesized that there would be a greater proportion of mature males in D than U. We found that body size of males that reproduced was similar to migrants that migrated the subsequent spring and larger than other cohort members. Reproducing males had a larger body size than equal-aged males that delayed reproduction. Similarly, individuals that migrated had a larger body size than equal-aged individuals that migrated subsequently. The proportion of mature males was greater in D than in U. The fact that body size differentiation occurred late in ontogeny and that age of maturation and migration varied within cohorts suggests that the decision to mature or migrate might be conditionally dependent.

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