Effects of size and morphology on swimming performance in juvenile brown trout (Salmo trutta L.)

Abstract

– Our study assesses swimming capacity (speed and stamina) and possible morphometric determinants of locomotor performance of juvenile brown trout (Salmo trutta L.). We addressed these issues at the individual level to have an approach of the functional significance of intraspecific variation in morphological design. Both swimming speed and endurance time showed significant positive relationships with fish length. Size‐corrected values of speed and endurance time were negatively correlated suggesting a phenotypic trade‐off between burst and prolonged swimming. Size was also highly correlated with all the morphological variables measured. Therefore, we used the residuals of the regressions of those variables on fish length to remove the effect of body size. A principal components analysis (PCA) summarised the 12 morphological variables into two factors, which accounted for 44.3% of the variance. PC1 combined several measures of body depth and width, whereas PC2 represented mainly postanal length relative to abdomen length. Relationships between the scores of the two factors and size‐corrected values of maximum swimming speed and endurance time were weak. PC2 showed a significant positive relationship with endurance time; that is, individuals with longer caudal regions were able to swim against water flow for longer periods of time. Stoutness (PC1) showed a marginally significant negative correlation with endurance time. The lack of stronger relationships could be because of the low morphometric variability among the test individuals, all proceeding from the same population, reared in a common environment, and measured at the same ontogenetic stage.

Temperature-mediated morphology changes during metamorphic climax in the African clawed frog, Xenopus laevis

“…A reduction of SVL on the completion of metamorphosis will reduce the achievable burst speed of individuals that metamorphosed at higher temperatures. Burst speed has been shown to be largely dependent on SVL in Xenopus and many other species (Wilson and Franklin, 2000;Ojanguren and Brana, 2003;Walsh et al, 2007a) and can impact on an individual's survival (Eidietis, 2005;Husak, 2006). Both of these factors may reduce the survival probability of juveniles that metamorphosed at higher temperatures (Beck and Congdon, 2000;Altwegg and Reyer, 2003;Chelgren et al, 2006).…”

The trade-off between growth rate and locomotor performance varies with perceived time until breeding

“…We quantified swimming performance as the length of time a fish could swim against a constant strong current of water; this measure of swimming stamina has been used in previous studies (Ojanguren and Braña, 2000;Ojanguren and Braña, 2003;Royle et al, 2006) using several different species including sticklebacks (Álvarez and Metcalfe, 2005); the full details of the experimental setup are given elsewhere (see Álvarez and Metcalfe, 2005;Royle et al, 2006). Swimming performance in both experiments was measured twice: (1) when fish in the different manipulation groups had finished the phase of compensatory growth and had converged on the same mean size prior to breeding; and (2) 18weeks later (after the breeding season).…”

Fish hatchering and its effects on the morphology of Prochilodus lineatus (Actinopterygii: Prochilodontidae)

“…In this respect, a range of studies conducted, mainly in temperate countries, has demonstrated the existence of wide morphological differences between wild and farmed fish (Taylor, 1986;Swain et al, 1991;Pakkasmaa et al, 1998;Hard et al, 2000;Ojanguren and Brana, 2003;Cramon-Taubadel et al, 2005;Berejikian and Tezak, 2005;Solem et al, 2006;Belk et al, 2008).…”