Abstract
Effective management of exploited populations is based on an understanding of population dynamics and evolutionary processes. In spatially structured populations, dispersal is a central process that ultimately can affect population growth and viability. It can be influenced by environmental conditions, individual phenotypes, and stochastic factors. However, we have a limited knowledge of the relative contribution of these components and its interactions, and which traits can be used as reliable predictors of the dispersal ability. Here, we conducted a longitudinal field experiment aimed to identify traits which can be used as proxy for dispersal in juvenile brown trout (Salmo trutta L.). We measured body size and standard metabolic rates, and estimated body shapes for 212 hatchery-reared juvenile fish that were marked with individual codes and released in a small coastal stream in northwest Spain. We registered fish positions and distances to the releasing point after 19, 41, 60 and 158 days in the stream. We detected a high autocorrelation of dispersal distances, demonstrating that most individuals settle down relatively soon and then hold stable positions over the study period. Body size and fish shape were reliable predictors of dispersal, with bigger and more robust-set individuals being more likely to settle closer to the release site than smaller and more elongated fish. In addition, the analysis of spacing and spatial patterns indicated that the dispersal of introduced fish could affect the distribution of resident conspecifics. All together, these results suggest that stocking programs aimed to the enhancement of overexploited populations at fine spatial scales can be optimized by adjusting the size and shape of the introduced fish to specific management targets and environmental conditions.
Highlights
Effective management of exploited populations is based on an understanding of population dynamics and evolutionary processes
Intrinsic factors can arise from consistent individual differences and extreme competitive asymmetries, or if dispersal ability is under genetic c ontrol[7,8,9,10]
We explore whether body size, metabolic rate, and body shape can be used as predictors of dispersal and conform a dispersal syndrome, which may be helpful for designing efficient stocking programs
Summary
Effective management of exploited populations is based on an understanding of population dynamics and evolutionary processes. We were aimed to investigate the drivers of secondary dispersal and settlement in a freshwater fish (brown trout, Salmo trutta) whose populations are largely subjected to invasive management (e.g., exploitation, stocking, and introduction in novel environments) by combining physiological and morphometric data with a longitudinal field experiment maintained over more than five months. In this context, we explore whether body size, metabolic rate, and body shape can be used as predictors of dispersal and conform a dispersal syndrome, which may be helpful for designing efficient stocking programs. Individuals with a higher metabolic rate, more robust shape or larger size could be more prone to disperse[24] because it can promote the exploration and settlement in new, more favourable grounds, since highly competitive individuals might overcome priority effects (the ‘explorer’ hypothesis)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
