Bridging expert knowledge and fishery data to examine changes in nearshore rockfish fisheries in the Gulf of Alaska over fifty years

Abstract

Rockfishes (Sebastes spp.) and the fisheries they support along the northeastern Pacific Ocean have undergone dynamic changes over the last century. The unique life history traits of rockfishes pose a host of challenges that make them difficult to monitor and susceptible to overfishing. Previous research has demonstrated that fishers’ knowledge and scientific data can help to create a more complete picture of long-term changes in rockfish populations and nearshore ecosystems. In this study, we used a multiple evidence-based approach that draws together expert knowledge of fishers and fisheries agency staff with long-term harvest data to document recent changes in nearshore rockfish populations and fisheries in two regions along the Gulf of Alaska. Using quantitative and qualitative methods, we compiled and analyzed datasets from the Alaska Department of Fish and Game to summarize spatiotemporal trends in commercial and recreational rockfish harvest and interviewed fishers and agency staff about their observations of long-term changes in nearshore rockfish populations and fisheries. We focused on two communities in the eastern and central Gulf of Alaska for which rockfish issues have been at the fore of management in recent years: Sitka and Kodiak, Alaska. We synthesized harvest data and abundance indices from expert knowledge in the context of fishery regulation changes to gain a more holistic perspective on the recent history of Alaska rockfish fisheries. While increases in localized fishing pressure and declines in relative abundance underlie concerns about pelagic and yelloweye rockfish populations and fisheries, stable or high abundance and proactive management for some species and locations also yield an optimistic outlook about their status. Variables such as gear type, sector, time periods fished, regulatory changes, and species targeted influenced experts’ perceptions of rockfish fisheries and populations. Our findings highlight the challenges of bringing together disparate data and the benefits of including multiple knowledge sources to produce a more complete understanding of complex fishery systems.