Predicting site-specific overwintering of juvenile brown trout (Salmo trutta) using a habitat suitability index

2009 ◽  
Vol 66 (4) ◽  
pp. 540-546 ◽  
Author(s):  
Daniel Palm ◽  
Eva Brännäs ◽  
Kjell Nilsson
Keyword(s):  
Brown Trout ◽  
Habitat Suitability ◽  
Salmo Trutta ◽  
Late Summer ◽  
Late Winter ◽  
Habitat Suitability Index ◽  
Site Specific ◽  
Suitability Index ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Trout

Brown trout ( Salmo trutta ) site-specific overwintering was studied in an ice-covered stream in northern Sweden. We monitored 238 individually tagged juvenile trout (body length 120–204 mm) from late summer until late winter using portable passive integrated transponder tag equipment and related it to a habitat suitability index. Minimum habitat suitability index explained a large portion (66.8%) of the variation in the proportion of individuals that remained and overwintered at specific sites from late summer until late winter. Our study design detected three scales of overwinter movements: (i) individuals that remained within their tagging site (site-scale movements); (ii) individuals that moved to other reaches (reach-scale movements), which were probably the most common; and (iii) individuals that left the study stream (stream-scale movements). There were no differences in size at tagging among individuals that adopted different scales of movements. We suggest that habitat suitability index can be used as a tool to predict site specific residency and, thus, habitat conditions in stream reaches during winter.

Invertebrate accessibility and vulnerability in the analysis of brown trout (Salmo trutta L.) summer habitat suitability

2002 ◽  
Vol 18 (6) ◽  
pp. 533-553 ◽  
Author(s):  
V. de Crespin de Billy ◽  
B. Dumont ◽  
T. Lagarrigue ◽  
P. Baran ◽  
B. Statzner
Keyword(s):  
Brown Trout ◽  
Habitat Suitability ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta

scholarly journals Regional prediction of basin-scale brown trout habitat suitability

2014 ◽  
Vol 364 ◽  
pp. 26-31 ◽  
Author(s):  
S. Ceola ◽  
A. Pugliese
Keyword(s):  
Prediction Model ◽  
Brown Trout ◽  
Habitat Suitability ◽  
Salmo Trutta ◽  
Ecological Indices ◽  
Regional Prediction ◽  
Basin Scale ◽  
Brown Trout Salmo Trutta ◽  
The Usa ◽  
Flow Duration Curves

Abstract. In this study we propose a novel method for the estimation of ecological indices describing the habitat suitability of brown trout (Salmo trutta). Traditional hydrological tools are coupled with an innovative regional geostatistical technique, aiming at the prediction of the brown trout habitat suitability index where partial or totally ungauged conditions occur. Several methods for the assessment of ecological indices are already proposed in the scientific literature, but the possibility of exploiting a geostatistical prediction model, such as Topological Kriging, has never been investigated before. In order to develop a regional habitat suitability model we use the habitat suitability curve, obtained from measured data of brown trout adult individuals collected in several river basins across the USA. The Top-kriging prediction model is then employed to assess the spatial correlation between upstream and downstream habitat suitability indices. The study area is the Metauro River basin, located in the central part of Italy (Marche region), for which both water depth and streamflow data were collected. The present analysis focuses on discharge values corresponding to the 0.1-, 0.5-, 0.9-empirical quantiles derived from flow-duration curves available for seven gauging stations located within the study area, for which three different suitability indices (i.e. ψ10, ψ50 and ψ90) are evaluated. The results of this preliminary analysis are encouraging showing Nash-Sutcliffe efficiencies equal to 0.52, 0.65, and 0.69, respectively.

Recruitment and survival rate variability in fish populations: density-dependent regulation or further evidence of environmental determinants?

2014 ◽  
Vol 71 (2) ◽  
pp. 290-300 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Environmental Factors ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Survival Rates ◽  
Fish Populations ◽  
Data Set ◽  
Site Specific ◽  
Density Dependent ◽  
Long Term Study ◽  
Brown Trout Salmo Trutta

Recently, Minto et al. (2008) , based on a fishery data set including marine, estuarine, and freshwater fishes, described higher variability in the survival rates of juveniles at low rather than at high parental density in an inversely density-dependent fashion and suggested density-dependent mechanisms underpinning those patterns. This study, based on a long-term study of brown trout (Salmo trutta; a species and habitat not included in the Minto et al. (2008) analysis), documents that survival rates in these stream-living populations exhibit a pattern that matches exactly those reported by Minto et al. (2008) . Nevertheless, hypothesis testing rejected the occurrence of stock–recruitment relationships and the operation of density-dependent recruitment regulation. The patterns elucidated for these brown trout populations can be entirely explained by the operation of two single environmental factors, namely, stream discharge in March determining annual survival rates across streams and sites and site-specific depth determining site-specific survival rates. It is open to question that exactly the same patterns can be generated by two sets of opposing factors, density-dependent (i.e., Minto et al. 2008 ) and environmental factors (i.e., this study). The consistency of this pattern suggests that survival rates and recruitment are probably determined by environmental factors across fish populations and habitats.

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.

Habitat quality enhances spatial variation in the self-thinning patterns of stream-resident brown trout (Salmo trutta)

2008 ◽  
Vol 65 (9) ◽  
pp. 2006-2015 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Brown Trout ◽  
Carrying Capacity ◽  
Salmo Trutta ◽  
Common Mechanism ◽  
Second Phase ◽  
Two Phase ◽  
Site Specific ◽  
Habitat Factors ◽  
Brown Trout Salmo Trutta ◽  
Two Phases

This study explored the extent to which variation in habitat factors related to growth and density influence self-thinning patterns in stream-living brown trout ( Salmo trutta ). Analysis of 110 cohorts at 12 sites of four contrasting streams revealed density–mass relationships in two phases. Density of survivors decreased little during the first half of their lifetime. A second phase commenced as individuals attained a threshold mass upon which density declined linearly with increased mass. The slopes of the second phase were greater than predicted by space and food demands. Among sites, these slopes were related to threshold densities at the beginning of the second phase. In turn, elevations, threshold densities, and slopes depicted concave trajectories against site depth, whereas threshold masses increased linearly. Apparently, cohorts remain below the carrying capacity during the first half of their lifetime and self-thin during the second half. Space-limited habitats impose site-specific carrying capacities and site-specific self-thinning coefficients, suggesting a common mechanism underlying self-thinning and an unanticipated, emerging property: two-phase patterns with far more variation in self-thinning coefficients. Variability in growth and density exhibited by brown trout and other salmonids across regions suggests that two-phase patterns may occur broadly, and self-thinning coefficients may vary widely.

Seasonal changes in habitat use and preference by juvenile brown trout, Salmo trutta, in a northern boreal river

1997 ◽  
Vol 54 (3) ◽  
pp. 520-530 ◽  
Author(s):  
A Maki-Petäys ◽  
T Muotka ◽  
A Huusko ◽  
P Tikkanen ◽  
P Kreivi
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Aquatic Vegetation ◽  
Habitat Availability ◽  
Size Classes ◽  
Stream Management ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout ◽  
Boreal River ◽  
Juvenile Trout

By means of electrofishing, we examined seasonal and size-class variation in habitat preference by juvenile brown trout (Salmo trutta) in a third-order river in northern Finland. Larger trout preferred deeper stream areas than young-of-the-year fish. At the onset of winter, all trout size-classes moved into shallower water, but this mainly reflected seasonal variation in habitat availability. In winter, trout preferred slowly flowing stream areas, whereas in other seasons the mean water velocities used by trout parallelled habitat availability. In summer and autumn, age-0 fish favoured stream areas with large amounts of aquatic vegetation to provide cover. The largest trout (16-22 cm) occupied habitats with little cover throughout the year, and in winter, all trout avoided areas with high instream cover. In summer, all size-classes preferred small substrates, whereas in winter, areas with cobble-boulder substrates were preferred, especially by trout larger than 10 cm. Wintering trout often shelter among the interstitial spaces of coarse substrates, and to facilitate the survival of juvenile trout through winter, stream management programmes need to ensure that such particles are abundantly available in trout wintering areas.

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