Comparison of temperature preference and metabolic thermal sensitivity between two juvenile coastal shark species


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


107-10  Sat Jan 2  Comparison of temperature preference and metabolic thermal sensitivity between two juvenile coastal shark species Skelton, ZR*; Wegner, NC; Prinzing, TS; Hastings, PA; Scripps Institution of Oceanography, University of California San Diego; Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration ; Earth to Oceans Research Group, Simon Frasier University; Scripps Institution of Oceanography, University of California San Diego zskelton@ucsd.edu

Sharks behaviorally thermoregulate in order to optimize physiological processes. Juvenile sharks often utilize estuaries, which can provide warm water temperatures that increase metabolism and facilitate growth. Both the California Horn Shark (Heterodontus francisci) and the Leopard Shark (Triakis semifasciata) occupy estuaries as juveniles and represent contrasting activity levels; horn sharks are relatively sedentary while leopard sharks are more active and mobile. The aim of this study was to better understand the relationship between behavioral thermoregulation and metabolism in response to temperature in these two species. Our objectives were threefold: 1) identify the temperatures juveniles prefer, 2) assess the sensitivity of metabolism (Q10) to temperature via measurements of oxygen consumption, and 3) compare these results across species, sex, and seasonal acclimation treatments. Using a shuttlebox system, our results show that juvenile horn sharks and leopard sharks have comparable thermal preferences and temperature ranges. While leopard sharks exhibited higher metabolic rates than horn sharks across all temperatures, horn sharks exhibited a higher relative overall Q10 suggesting their metabolism has greater thermal dependence. There was no effect of seasonal temperature acclimation on any of our tested parameters. Compared to leopard sharks, horn sharks likely target stable-temperature environments closer to their preferred temperature. This work highlights the importance of temperature-induced physiological and behavioral responses in understanding habitat use during vulnerable life stages.

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