Meeting Abstract

P2-172  Sunday, Jan. 5  Comparison of Temperature Preference and Q₁₀ Between Two Juvenile Shark Species SKELTON, ZR*; WEGNER, NC; PRINZING, TS; HASTINGS, PA; University of California, San Diego; Southwest Fisheries Science Center, NOAA Fisheries ; Simon Fraser University; University of California, San Diego zskelton@ucsd.edu

Many ectotherms, including sharks, behaviorally thermoregulate to optimize physiological processes. Juvenile sharks often utilize estuaries as nursery grounds, that, among other benefits, provide warm water temperatures that increase metabolism and facilitate growth. Discerning how temperature influences the behavior and physiology at the juvenile life stage is important in understanding how environmental changes (e.g. human encroachment and climate change) may affect the distribution and movement of local species. Here we compare two abundant coastal species that possess contrasting activity levels: the benthic horn shark (Heterodontus francisci) and the demersal leopard shark (Triakis semifasciata). The aim of this study was to isolate temperature as a single variable to investigate the relationship of behavioral thermoregulation and metabolism. The objectives were threefold: 1) identify the temperatures juveniles prefer and avoid, 2) assess how temperature affects metabolism (Q₁₀) via measurements of oxygen consumption, and 3) compare between sexes and species. Both species exhibited increasing metabolic rates with increasing temperatures. Leopard sharks exhibited higher metabolic rates than horn sharks across all temperatures. However, horn sharks exhibited a higher overall Q₁₀ suggesting they may experience greater metabolic stress traveling across thermal regimes. Our results suggest horn sharks are more likely to target environments closer to their preferred temperature than leopard sharks. Ultimately, this baseline assessment should be paired with future in situ tracking to elucidate the role of these parameters on habitat selection in juvenile sharks.