Sexual Segregation of Spiny Dogfish (Squalus acanthias) in Fishery-Dependent Surveys in Cape Cod, Massachusetts: Potential Management Aspects

The international exploitation of the gonochoristic and sexually segregated spiny dogfish (Squalus acanthias) is driven by the European market, which favors large females. This sex-selective demand is likely affecting the fishery sustainability of the U.S. Atlantic stock, which is measured using the spawning stock biomass of adult females as a main reference point. A potential management strategy to enhance the fishery sustainability would be the development of a male-only directed fishery in areas characterized by a consistent and predictable presence of males, although this information is currently lacking. We conducted fishery-dependent surveys for spiny dogfish in the Cape Cod, Massachusetts area to assess if the percentage of males in the catch changes throughout a normal fishing day, an event frequently observed by local commercial longliners. A consistent seasonal (summer and early fall) diurnal shift in the sex ratio was found within 10 miles off the east coast of Cape Cod. This shift suggests the potential for a pilot study testing the viability of a male-only directed longline fishery in this area based on season and time of the day. Such a fishery would enhance the sustainability of the U.S. Atlantic spiny dogfish stock by reducing fishing pressure on adult females