Downscaled Seasonal Forecasts for Living Marine Resource Management off the US West Coast

One of the greatest challenges in fisheries management is balancing environmental and economic interests by maintaining productive fisheries while limiting bycatch. Static closure rules are often inefficient in this regard, and momentum is building to employ management strategies informed by environmental conditions and predicted species distributions. One such example off the US west coast is the California Current System (CCS) drift gillnet fishery (DGN), whose regulations are enacted by NOAA/NMFS. The DGN targets sustainable stocks of commercially valuable swordfish, but accidental take of non-targeted species (e.g., turtles, cetaceans, sea lions) has led to large-scale fishery closures and declining productivity of the DGN fleet. Recently, dynamic management strategies for the DGN have been explored using observations and statistical models to predict target- by-catch species distributions in near real time, allowing managers to reexamine specific closure rules. Extending these efforts to seasonal forecasts would enhance their utility by giving managers additional time for adaptive responses, but no forecast system currently exists that offers sufficient spatial resolution to capture key physical processes in the CCS and the broad spatial coverage needed to manage wide-ranging fish, turtles, and marine mammals. We propose to produce and validate downscaled seasonal reforecasts for ~3 decades of CCS physical conditions as well as species distributions for target- and by-catch species of interest to US west coast fisheries. Key elements of the proposed work plan are (1) extract and bias-correct global NMME fields, use them to force downscaled reforecasts (i.e., retrospective forecast experiments predicting what happened in the past) of CCS physics, and validate CCS reforecasts with observations, (2) run and validate species distribution reforecasts for target- and by-catch species in the CCS, and (3) determine the added value of an ensemble approach to forecasting living marine resources. Environmental and fisheries data for validating 30+ years of reforecasts is already in hand. The proposed project will provide (i) a set of downscaled seasonal climate reforecasts that can be applied to diverse science and management questions, (ii) target-and by-catch species distribution reforecasts that can be used to reexamine DGN closure rules in collaboration with NOAA/NMFS partners, and (iii) a seasonal forecasting framework that can be applied in fisheries management off the US west coast and elsewhere.

Climate Risk Area: Marine Ecosystems