title: Coming up for air: thermal dependence of dive behaviours and metabolism in sea snakes.
abstract: Cutaneous gas exchange allows some air-breathing diving ectotherms to supplement their pulmonary oxygen uptake, which may allow prolongation of dives and an increased capacity to withstand anthropogenic and natural threatening processes that increase submergence times. However, little is known of the interplay between metabolism, bimodal oxygen uptake and activity levels across thermal environments in diving ectotherms. Here, we show in two species of sea snake (spine-bellied sea snake, Hydrophis curtus; and elegant sea snake, Hydrophis elegans) that increasing temperature elevates surfacing rate, increases total oxygen consumption and decreases dive duration. The majority of dives observed in both species remained within estimated maximal aerobic limits. While cutaneous gas exchange accounted for a substantial proportion of total oxygen consumption (up to 23%), unexpectedly it was independent of water temperature and activity levels, suggesting a diffusion-limited mechanism. Our findings demonstrate that rising water temperature and a limited capability to up-regulate cutaneous oxygen uptake may compromise the proficiency with which sea snakes perform prolonged dives. This may hinder their capacity to withstand ongoing anthropogenic activities like trawl fishing, and increase their susceptibility to surface predation as their natural environments continue to warm.
authors: Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia vinay.udyawer@my.jcu.edu.au.|Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
authors: Vinay
authors: 0000-0001-5812-0740
authors: V
authors: Udyawer
authors: Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia.
authors: Colin A
authors: CA
authors: Simpfendorfer
authors: Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia.|Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
authors: Michelle R
authors: MR
authors: Heupel
authors: Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
authors: Timothy D
authors: TD
authors: Clark
mesh_terms: D000388:Air; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D004242:Diving / Q000502:physiology*; D017815:Elapidae / Q000378:metabolism* / Q000502:physiology*; D008168:Lung / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D013696:Temperature
keywords: Accelerometer; Aerobic limits; Bimodal gas exchange; Hydrophis (Lapemis) curtus; Hydrophis elegans; Incidental trawl bycatch