Most bycatch survival data is empirical: fish either survive, or they do not. We conduct trials in which, in lieu of a return to the ocean, relevant species are held in pens at sea and in the captive environment to monitor survival rates in the post-capture period.
Following capture and at other discrete intervals, we analyze the blood constituents of these animals to help elucidate the degree of physiological alteration elicited by capture (and alternate stressors). Together, these data can help establish the degree of stress imposed, the recovery potential of particular species or size classes, and can help estimate the more deleterious aspects of the capture experience. Beyond its intrinsic value, such information can also be used as a basis for regulatory policies and to promote more informed decisions about the best ways to contest the reported declines in relevant fish populations.
We investigated the blood chemistry and mortality rate of under-sized Atlantic cod accidentally captured in the New England longline fishery.