SEMINAR: MAF Seminar

[Maria Luisa Estevanez <mestevanez@rsmas.miami.edu>]

MAF Seminar
Friday, September 23, 2011
10:30 am - 11:30 am
SLAB 103

Speaker: Austin J. Gallagher
Ph.D. Student, Research Assistant,
Abess Center for Ecosystem Science and Policy
R.J. Dunlap Marine Conservation Program

Title: "Stressed out: Consequences of fisheries capture and release on the physiology, behavior, and survival of sharks in the subtropical Atlantic"

Abstract:

Commercial fishing activities have been repeatedly identified as a major contributor to the global decline of predatory fish populations including sharks, and there is a growing effort to understand the effects of bycatch and minimize mortality of discarded individuals. The recreational sector also encounters sharks both incidentally and as targeted fisheries with some harvested, and others released (voluntarily or as a result of regulations), facing an uncertain fate.  While there have been a wide range of studies covering the issue of release survival and physiology in various game fishes, similar studies on elasmobranchs-particularly threatened species of shark-are lacking. To address the paucity of knowledge on the sublethal consequences and delayed mortality associated with shark-fishery interactions, we conducted an integrative study that employed physiological (blood chemistry), behavioral (reflex tests), and survival assessments (satellite tagging) across 5 coastal species of shark found in the subtropical Atlantic. Results suggest significant species differences, with tiger and lemon sharks showing a high tolerance for stress as a result of fishing pressure, whereby other species such as the great hammerhead and bull displayed extreme acid-base disruption and reflex inhibition across fight times, as well as increased post-release mortality. Results are framed within the context of varying exercise regimes and inter-specific stress responses/capacities, while providing a basis for future ecological risk assessment.