The ontogenetic development of body segments and sexual dimorphism in brown trout (Salmo trutta L.)

1997 ◽  
Vol 75 (4) ◽  
pp. 651-655 ◽  
Author(s):  
F. G. Reyes-Gavilán ◽  
A. F. Ojanguren ◽  
F. Braña
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Head Length ◽  
Northern Spain ◽  
Morphometric Traits ◽  
Brown Trout Salmo Trutta ◽  
Selection For ◽  
Mature Fish

Nonmigratory brown trout (Salmo trutta L.) from northern Spain showed no between-sex differences in total length or mass and only moderate, but significant, dimorphism in some morphometric traits. The main dimorphic features were the sizes of the abdomen (larger in females) and head (larger in males, including the upper jaw), relative to each other and also to the post-anal length, the latter being considered a control for body size. Least-squares linear regressions of head length on abdomen length were homogeneous in both the slopes and the intercepts for immature fish of both sexes, but mature males exhibited significantly steeper slopes than mature females. Within each sex the slopes for immature and mature fish were homogeneous, and mature fish of both sexes had higher intercepts than immature ones. Therefore, immature individuals were monomorphic and mature individuals of both sexes diverged from the juvenile pattern, each in a particular fashion: males acquired a greater relative head length (particularly a longer jaw) and females a greater relative abdomen length. Sexual selection for larger head size relative to body size in males and fecundity selection for larger abdomen size relative to body size in females are hypothesized to be important in the evolution of sexual dimorphism in brown trout.

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.

Phylogeographical lineages in brown trout (Salmo trutta) : investigating microgeographical differentiation between native populations from Northern Spain

2002 ◽  
Vol 47 (10) ◽  
pp. 1879-1892 ◽  
Author(s):  
M. Elena Cagigas ◽  
Emilia Vázquez ◽  
Gloria Blanco ◽  
José A. Sánchez
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Northern Spain ◽  
Native Populations ◽  
Brown Trout Salmo Trutta

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.

Cryptic prey colouration increases search time in brown trout (Salmo trutta): effects of learning and body size

2008 ◽  
Vol 62 (10) ◽  
pp. 1613-1620 ◽  
Author(s):  
Jörgen I. Johnsson ◽  
Karin Kjällman-Eriksson
Keyword(s):  
Body Size ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Search Time ◽  
Brown Trout Salmo Trutta

Small-scale dispersal and population structure in stream-living brown trout (Salmo trutta) inferred by mark–recapture, pedigree reconstruction, and population genetics

2012 ◽  
Vol 69 (9) ◽  
pp. 1513-1524 ◽  
Author(s):  
Leif Asbjørn Vøllestad ◽  
Dimitar Serbezov ◽  
Arthur Bass ◽  
Louis Bernatchez ◽  
Esben Moland Olsen ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Isolation By Distance ◽  
Juvenile Fish ◽  
Age Groups ◽  
Small Scale ◽  
Mark Recapture ◽  
Small Stream ◽  
Brown Trout Salmo Trutta ◽  
Mature Fish

Many animals move among habitats, and even small-scale dispersal of individuals between habitat patches may have strong implications for population dynamics and structure. Here, we use long-term mark–recapture data combined with extensive genotyping and parentage assignment to investigate the importance of small-scale location change of resident brown trout ( Salmo trutta ) in a small stream (1500 m). During the first summer, juvenile fish dispersed downstream (mean displacement 200 m), with smaller juveniles dispersing longer distances. Downstream movement was also predominant during the first winter, but older fish moved little. This limited dispersal resulted in a significant isolation-by-distance structure for ages 1 and 2, but not for older age groups or for the mature fish. Individual pairwise relatedness coefficients decreased with waterway distance for mature fish during the 2002 and 2003 spawning seasons, but only weakly. Overall, between-site genetic differentiation was stronger for the younger age classes, and the signal decayed with age, indicating that the genetic structure observed in the stream is mainly driven by spatial aggregation of close relatives.

Sexual Dimorphism in Anal Fin of Brown Trout, Salmo trutta, and Close Relatives

1968 ◽  
Vol 25 (4) ◽  
pp. 813-815 ◽  
Author(s):  
C. G. Gruchy ◽  
V. D. Vladykov
Keyword(s):  
Sexual Dimorphism ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta ◽  
Close Relatives

not available

Development of galanin-like immunoreactivity in the brain of the brown trout (Salmo trutta fario), with some observations on sexual dimorphism

2003 ◽  
Vol 465 (2) ◽  
pp. 263-285 ◽  
Author(s):  
Miguel Angel Rodríguez ◽  
Ramón Anadón ◽  
Isabel Rodríguez-Moldes
Keyword(s):  
Sexual Dimorphism ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta ◽  
The Brain ◽  
Salmo Trutta Fario

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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