Abstract
Stress physiology is the study of factors related to stress responses that affect the physical condition of an animal and may result in sub-lethal effects or increases in post-release mortality. The secondary stress response, characterized by individual physiological and biochemical changes, is the focus of this study. Environmental factors such as water temperature, gear type, and fight time effect stress levels of sharks interacting with fishing gear. The capture stress response of some ram-ventilating, sub-tropical shark species have been studied, including blacktips and bonnetheads, however, little is known about capture stress in blacknose sharks (Carcharhinus acronotus). Blacknose sharks have a K-selected life history traits and their populations have undergone large declines in recent decades. They are targeted in commercial, artisanal, and recreational fisheries, but are also taken as non-target bycatch in some coastal fisheries. There is high variability between the stress response of even closely related species, so it is crucial to have species-specific data to understand the potential effects of capture. Blacknose sharks were caught as part of a scientific longlining survey and two blood samples were taken from each shark: one when the shark was first brought on board, and one following the completion of a brief scientific workup, immediately before release. The results show that sea surface temperature influence lactate levels in blacknose and blacktip sharks. This information can be used to enhance understanding of capture stress when blacknoses are captured in recreational fisheries or as unwanted bycatch.