Commercial Salmon Fishing Behavior on the West Coast During Changing Ocean Conditions

We report on the behavior of the commercial salmon fishing fleet on the West Coast of the United States before and during a recent extreme oceanographic event. The West Coast experienced a marine heatwave during 2014-16, during which ocean temperatures significantly exceeded long-term averages. Previous studies have described the biological impacts of this heatwave, including harmful algal blooms and northward species migration, but less is known about the response of fishing industry participants and communities. We use Vessel Monitoring System (VMS) data to describe the spatial distribution of a subset of the salmon fishing fleet from 2007 through 2016. We use this data to analyze year-to-year and within-season changes in fishing location and trip characteristics (e.g., distance and duration). We generate fleet-level spatial indicators of vessel position over time and overlay positions with oceanographic indicators, such as Sea Surface Temperature, to visualize how fishing location may be affected by oceanographic conditions. We complement this analysis by using over 30 years of commercial salmon landings data to further describe changes that have occurred and understand the variability inherent in this fishery. Preliminary results indicate that during the MHW 1) coastwide commercial salmon landings were much lower than historical norms, 2) fishing locations shifted northward, as indicated both by vessel position data and the location of landings, and 3) salmon fishing trips were longer (in terms of distance from port and number of days at sea per trip). Our analysis is primarily exploratory, but can lead to better estimates of the economic impacts of extreme oceanographic events and improve projections of the effects of climate change on fishing fleets and communities. Work on this project to date is one of the earliest scientific applications of VMS data on the West Coast and has helped develop VMS as a data source to inform future science and management.