Dive-depth distribution of loggerhead (Carretta carretta) and olive ridley (Lepidochelys olivacea) sea turtles in the central North Pacific: Might deep longline sets catch fewer turtles?

摘要

An important aspect of fisheries management is the correct delineation of boundaries between fish stocks. With the recent collapse of the groundfish fishery in eastern Canada, redfish (Sebastes spp.) has become an increasingly important resource. Currently, the two most economically important redfish species (S. fasciatus and S. mentella) are partitioned into eight management areas in the Northwest Atlantic (Fig. 1). In this study, we examined the parasite fauna of the deepwater redfish S. mentella, collected from different areas in the Northwest Atlantic, to determine if the distribution and abundance of the parasite fauna can aid in stock discrimination of this species and focused on differentiating fish from the Gulf of St. Lawrence (unit 1) from those from the Cabot Strait and Laurentian Channel (unit 2). The deepwater redfish is the most common redfish species in the Gulf of St. Lawrence and is considered to have a more northerly range and deeper distribution than its congeners (Atkinson, 1987; Scott and Scott, 1988).