BERNAL, Diego*; SEPULVEDA, Chugey; University of Massachusetts, Dartmouth; Pfleger Institute of Environmental Research: Molecular indicators of capture related stress in pelagic sharks captured with different fishing gear

The post-release survivorship of hooked fishes is a key assumption underlying many recreational fishing practices and the reduction of commercial bycatch of non-targeted fishes. However, little is understood about how cellular stress-threshold-indicator levels correlate with the post-release survivability. Although, most fishes can recover from acute bouts of exhaustive exercise, intense and repeated struggling during capture may lead to significant tissue damage and critical disruptions to homeostasis resulting in higher rates of long-term (>30 days) post-release mortality. This study quantified the presence of specific molecular indicators of cellular stress (i.e., Hsp, heat shock proteins 70 and 90) in the blood of sharks with different levels of swimming activity (i.e., the active shortfin mako shark and the sluggish blue shark) in responses to capture with sportfishing gear and commercial longline gear. Preliminary results for sportcaught sharks show an increase in the levels of Hsps as a function of angling time (i.e., struggle stress) in the mako shark and relatively smaller response in the blue shark. No apparent pattern has emerged for the longline caught specimens. When the levels of Hsps are compared between the two capture techniques, a higher stress response appears to be present in fishes caught with the commercial gear. Taken together, this preliminary study provides an initial assessment of molecular stress response in sharks and will serve as the foundation for future studies on the long-term molecular responses to capture related stress in fishes.