Reducing Gill-Net Mortality of Incidentally Caught Coho Salmon

Abstract

The abundance of coho salmon Oncorhynchus kisutch has declined dramatically over much of the southern part of its range along the Pacific Coast of North America. This decline has created the need to reduce fishing mortalities, including bycatch mortalities in fisheries that are targeting other species. Traditional gill-net fishing causes an estimated 35–70% mortality rate on incidentally caught coho salmon. A reduction in this high mortality rate is necessary if gill nets continue to be used in fisheries that inadvertently intercept depressed coho salmon stocks while fishing other species. By using modified gear, short net soak times, careful handling of fish on removal from the gill net, and a newly designed recovery box, the short-term mortality rate on incidentally caught coho salmon can be reduced to as little as 6%, possibly even lower in some circumstances. This substantial reduction in mortality on nontargeted species expands the possible role of gill nets in the development of selective fisheries.