ABSTRACT
Despite their long evolutionary history (~400 million years; Grogan and Lund 2004), elasmobranchs are now facing new substantial anthropogenic threats, including habitat degradation and fisheries interactions, which cause acute and chronic stress that may exceed stress levels typically imposed by natural events (e.g., seasonal habitat changes, predator avoidance). Although the physiological stress response of teleosts has been studied for decades (e.g., Adams 1990a), much of this work has centered on salmonids due to the ease of maintaining and manipulating these fishes in captivity as well as the economic interests of the aquaculture industry and the recreational fishing sector. The global expansion of both commercial and recreational fisheries coupled with the mandated release of captured fish due to bag limits, quotas, and minimum sizes, prompted the expansion of stress studies beyond freshwater teleosts to their marine counterparts. However, studies of elasmobranch stress physiology have lagged far behind despite the rapid proliferation of directed fisheries for, and a significant increase in the incidental capture of, these species over the last two decades (NMFS 2008) and the possibility that modifications to coastal habitats, which are important to many elasmobranch species, could increase stress.
