Biology of Acadian redfish and implications for optimum yield in a mixed‐species fishery

No abstracts are to be cited without prior reference to the author.

The New England fishery for Acadian redfish (Sebastes fasciatus) is managed as part of the mixedspecies demersal fishery. The fishery was traditionally managed according to the status of principal groundfish species: Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinnus), and yellowtail flounder (Limanda ferruginea), and recent management of each stock remains largely focused on gadoid and flatfish species. However, the life history of redfish differs from that of other species in the fishery in several important ways. The live‐bearing reproductive strategy of redfish (ovovivipary) is associated with much lower fecundity than that of other gadoid and flatfish species and may involve depensatory forms of density‐dependent stock–recruit relationships. Redfish have much greater longevity, lower natural mortality rate, and slower growth than other New England groundfish. Their morphology also confers size‐selectivity patterns different to those of gadoids or flatfish. The life‐history strategy of redfish makes it more vulnerable to overfishing and less resilient than other species in the fishery. Although the history of the New England redfish fishery includes serial depletions that are consistent with life‐history expectations, recent stock rebuilding and strong recruitment offer prospects for a productive and sustainable fishery. Life‐history information is considered in the overfishing limit (50% of maximum spawning potential compared with 40% for other groundfish), but the fishing mortality rate associated with overfishing is much less than that for other species. Therefore, mixed‐species fishing effort is more likely to overfish redfish than other species. If redfish are targeted with smaller mesh that is commensurate with their relatively small size at maturity, then the opposite problem of incidental bycatch of immature sizes of other species (e.g. cod and pollock, Pollachius virens) should be considered. Based on the biology of redfish as compared with life histories of other New England groundfish and experience from other mixed‐species demersal fisheries including Sebastes species, redfish should be selectively targeted and managed within sustainable catch limits to achieve optimum yield.