Characteristics of Shark Bycatch Observed on Pelagic Longlines off the Southeastern United States, 1992-2000

摘要

In some commercial fishing operations, elasmobranchs represent a significant amount of discarded bycatch. Due to the slow growth rate, late maturity, and low fecundity of sharks in general, shark populations are particularly vulnerable to fishing pressure (Pratt and Casey, 1990). The history of directed shark fisheries in North American waters contains many examples of the deleterious effects overfishing can have on shark populations, including the rise and collapse of the porbeagle, Lamna nasus (Casey et al., 1978); soupfin shark, Galeorhinus zyopterus (Ripley, 1946); and spiny dogfish, Squalus acanthias (Rago et al., 1998) fisheries. Even in the case of species not subject to directed fisheries, such as many pelagic sharks, there is concern that bycatch mortality may still be high enough to harm shark populations (Musick et al., 2000). This concern has led to an urgent call for population assessments of elasmobranch species that often appear as bycatch in pelagic commercial fishing operations.