The importance of recruitment for the production dynamics of stream-dwelling brown trout (Salmo trutta)

2005 ◽  
Vol 62 (11) ◽  
pp. 2484-2493 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Growth Patterns ◽  
Minor Role ◽  
Second Phase ◽  
Productive Capacity ◽  
Cohort Size ◽  
Two Phase ◽  
Brown Trout Salmo Trutta ◽  
Production Dynamics

The objective was to highlight the role of recruitment for production dynamics of stream brown trout (Salmo trutta). The analysis of 51 cohorts (hatched in 1986–1999) at four sites of Rio Chaballos (northwestern Spain) showed sinusoidal growth patterns with more intense growth in spring and summer and reduced growth in winter. Survivor abundance described two-phase trajectories over the lifetime (1000–1400 days after emergence). A first phase of negligible or no mortality was prolonged for 500–650 days. Severe mortality during the second phase differed among cohorts and among sites. Spatiotemporal variations in growth, mortality, density, spawner abundance, biomass, and production underlay variations in recruitment. Increased recruitment affected growth negatively (except at one site) and mortality positively. Cohort production decreased with increased growth at three sites but increased with increased growth at another site. Greater mortality typified the most productive cohorts. However, 90.8% and 83.6% of the variations in density and production, respectively, were explained by variations in recruitment. Thus, cohort size and production appeared to be determined by recruitment in which postrecruitment processes played a minor role. Recruitment reset the cohort's numerical and productive capacity, and increments in recruitment continued to increase cohort size and production over the recruitment magnitudes observed across sites and years.

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.

scholarly journals Temperature affects growth allometry and development patterns in brown trout (Salmo trutta) fry: a multitrait approach

2018 ◽  
Vol 75 (5) ◽  
pp. 714-722 ◽  
Author(s):  
Emilie Réalis-Doyelle ◽  
Enric Gisbert ◽  
Carles Alcaraz ◽  
Fabrice Teletchea ◽  
Alain Pasquet
Keyword(s):  
Brown Trout ◽  
Growth Phase ◽  
Salmo Trutta ◽  
Developmental Stages ◽  
Growth Patterns ◽  
Second Growth ◽  
Brown Trout Salmo Trutta ◽  
Allometric Analysis ◽  
The Impact ◽  
Skeletal Mineralization

To study the influence of temperature (4, 6, and 12 °C) on the development of brown trout (Salmo trutta) from hatching to the end of metamorphosis, an analysis of allometric growth patterns was conducted to identify two different groups of individuals, namely developmental phases at total lengths (TL) ranging from 2.72 cm at 4 °C to 2.22 cm at 12 °C. Then, a multitrait approach considering different variables like the survival rate, development time, morphometric characteristics, energetic value, and skeletal mineralization was conducted on these two groups. Results indicated that the first growth phase was slower at 4 °C, whereas the second was also slower at this temperature, even though swimming behavior was already present. However, at 12 °C, fry showed a delay in their development (i.e., lower levels of skeletal mineralization and energetic content) during the first growth phase, but they compensated during the second growth phase, reaching the same size in TL when compared with the other temperatures (4 and 6 °C); fry at 12 C° showed low energy reserves. Our study demonstrated that the use of an allometric analysis to identify different developmental stages coupled with a multitrait approach was more efficient than a classical distinction between biological stages (hatching, emergence, first food intake, and exogenous feeding), and this procedure is of interest when evaluating the impact of rearing conditions on early development in fish.

Differences in Brown Trout (Salmo trutta) Production among Contiguous Sections of an Entire Stream

1989 ◽  
Vol 46 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Raymond M. Newman ◽  
Thomas F. Waters
Keyword(s):  
Growth Rate ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Standing Stock ◽  
Production Factors ◽  
Habitat Differences ◽  
Brown Trout Salmo Trutta ◽  
Standing Stocks ◽  
Relative Differences ◽  
Production Dynamics

Production dynamics of a wild brown trout (Salmo trutta) population were examined for 3 yr in each of eight contiguous 305-m-long sections that constituted the entire length of South Branch Creek, a limestone stream in southeastern Minnesota. Total trout densities increased from about 1600/ha in 1980 to 2300/ha in 1982. There were large and significant differences in density among sections; relative differences among sections, however, were nearly constant over the 3 yr. Mean annual standing stock and production increased over the 3 yr from about 90 and 100 kg/ha, respectively, in 1980 to 150 and 174 kg/ha, respectively, in 1982. Standing stock and production also differed significantly among sections, but relative differences among sections were fairly constant over the 3 yr. The most productive sections had standing stocks and production rates that were 1.5–2 times higher than the least productive sections. Year strongly influenced growth rate, with growth in 1982 almost double that in 1981, but growth rates did not differ significantly among sections. Habitat differences among sections appeared to regulate density, size, standing stock, and production. Factors that affected the entire stream influenced recruitment and growth.

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