Density-dependent effects of prior residence and behavioural strategy on growth of stocked brown trout (Salmo trutta)

2004 ◽  
Vol 82 (10) ◽  
pp. 1638-1646 ◽  
Author(s):  
Eva Brännäs ◽  
Sara Jonsson ◽  
Kurt Brännäs
Keyword(s):  
Growth Rate ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Lower Growth ◽  
Density Dependent ◽  
Behavioural Strategy ◽  
Behavioural Factor ◽  
Brown Trout Salmo Trutta ◽  
Prior Residency ◽  
Effect On Growth

When animals face temporally periods of strong intraspecific competition, prior residency, available resources, and their competitive abilities in terms of size and behavioural strategy affect their chances of survival. Density, individual size, and behavioural strategy had the strongest effect on growth. The mean growth rate of both resident and intruding brown trout (Salmo trutta L., 1758) decreased with increasing density, and the largest individuals were the most successful ones independently of the density of prior residency. An aggressive behavioural factor was beneficial at the lowest and intermediate densities, whereas a nonaggressive behavioural factor was beneficial at higher densities. Prior residency had no overall significant effect on growth, as the effect was highly density-dependent. The difference in growth rate between introduced and resident individuals was significant only at high density and low food abundance per individual. The intruders had a significantly lower growth rate at high densities and fewer individuals had a high growth rate. These results suggest that stocking fish at densities exceeding the carrying capacity of the habitat results in fewer individuals that are able to compete for resources than if fewer individuals were stocked. Brood stock can then be used in a more efficient way.

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.

Spatial and temporal variation in the influence of density dependence on growth of stream-living brown trout (Salmo trutta)

2005 ◽  
Vol 62 (6) ◽  
pp. 1231-1242 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
High Growth ◽  
Spatial And Temporal Variation ◽  
Data Sets ◽  
Negative Power ◽  
Density Dependent ◽  
Brown Trout Salmo Trutta ◽  
Dependent Growth ◽  
Size At Age

The objective of this study was to investigate the extent to which, and the conditions under which, density operated on growth in stream-living brown trout (Salmo trutta). Observational data of 14 cohorts at four sites of Rio Chaballos (northwestern Spain) were examined. Consistent relationships between cohort-specific mass versus cohort-specific density and between year-to-year variations in brown trout mass at the end of five successive life stages versus mean densities corroborated one another and provided compelling evidence for the occurrence of density-dependent growth. However, density-dependent patterns varied in nature among sites to the extent that they were site-specific. A further comparison among 12 data sets revealed a smooth negative power trajectory between juvenile mass versus density. This plot suggested that detection of density-dependent growth might be facilitated in low density – high growth populations located at the steep wing relative to high density – slow growth populations. Current results emphasized the importance of density as a factor determining size-at-age and supported its operation as epiphenomena capable to obscure the effects of temperature on growth. The operation of density-dependent growth on numerical regulation of the population is further discussed.

Effect of Feeding Brown Trout (Salmo trutta) a Diet Pelleted in Dry and Moist Forms

1974 ◽  
Vol 31 (11) ◽  
pp. 1824-1826 ◽  
Author(s):  
Hugh A. Poston
Keyword(s):  
Growth Rate ◽  
Body Composition ◽  
Energy Density ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Dry Matter ◽  
High Moisture ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout ◽  
Effect Of Feeding

Growth rate, body composition, and intake of either dry matter or energy did not differ significantly (P > 0.05) between two groups of juvenile brown trout (Salmo trutta) fed either a low- or high-moisture semipurified diet at different rates to compensate for a diet energy density gradient. Feed/gain efficiency, on an as-fed basis, was significantly greater (P < 0.01) in fish fed the low-moisture diet, but did not differ (P > 0.05) when compared on the basis of dry matter or energy intake.

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