Individual isotopic specializations predict subsequent inter‐individual variation in movement in a freshwater fish

Abstract

Abstract. Despite many similarities and intuitive links between individual dietary specialization and behavioral inter-individual variation, these phenomena have been studied in isolation, and empirical data confirming relationships between these intraspecific variance sources are lacking. Here we use stable isotope analysis and acoustic telemetry to test the hypothesis that individual specialization in trophic (δ 15 N) and littoral/pelagic prey reliance (δ 13 C) covary with inter-individual variation in movement in a group of 34 free-swimming burbot (Lota lota). By performing stable isotope analysis on tissues with differing isotopic turnover rates (anal fin and dorsal muscle), in 24 lethally sampled burbot, we demonstrate that individual specialization in trophic niche (δ 15 N) and littoral/pelagic prey reliance (δ 13 C) occurred within the population. By performing stable isotope analysis on anal fins of a group of telemetry tagged burbot, we were able to show that interactions between trophic niche and littoral/pelagic prey reliance, explained a significant proportion of the subsequent between-individual variance in mean movement rates. These findings demonstrate an empirical connection between behavioral inter-individual variation and dietary specialization, thus providing a substantial expansion of our understanding of the wider ecological consequences of these interesting phenomena.

Beaver activity increases habitat complexity and spatial partitioning by steelhead trout

“…Interestingly, there appears to be no apparent cost in growth rates for highly mobile juvenile steelhead compared to stationary individuals, indicating the potential importance of two disparate movement behaviours as a viable means to expanding population-level resource base and to reduce intra-specific competition for resources (Kahler et al 2001;Steingrímsson and Grant 2003;Myrvold and Kennedy 2016). Collectively, our findings in conjunction with previous work suggests that the diversity in beaver complex movement behaviours could be a manifestation of dietary niche expansion (Harrison et al 2017). Further, juvenile steelhead have shown strong diel movement capabilities to exploit thermal refuge (Brewitt and Danner 2014).…”

Personalities influence spatial responses to environmental fluctuations in wild fish

“…Alternatively, it might be possible that the differences in movement behaviour by the different personality types during summer might be due to correlated differences in the dietary specialization. Indeed, in burbot Lota lota , a freshwater gadoid fish, interindividual differences in movement behaviour were explained by the interaction between trophic niche and prey reliance (Harrison et al., ). Finally, reactive and proactive fish may have differences in how they manage uncertainty in their natural environment (Mathot, Wright, Kempenaers, & Dingemanse, ).…”

Diet and movements of pikeperch (Sander lucioperca) in a large oligotrophic lake with an exceptionally high pikeperch yield

“…Within‐lake movements of lentic fishes have received relatively little attention in research although high biomasses of large‐bodied fishes could potentially contribute to significant within‐lake energy and nutrient transfers (e.g. Harrison et al, ). Migration in freshwater fishes was previously thought to be relatively rare (Brönmark et al, ), and most studies until recently have focused on energy transfer from the marine environment to the spawning rivers of salmonids (e.g.…”