Cod Collapse and the Climate in the North Atlantic

Tuesday, 16 December 2014
Kyle Chuan Meng1, Kimberly Lai Oremus2 and Steve Gaines1, (1)University of California Santa Barbara, Santa Barbara, CA, United States, (2)Columbia University of New York, School of International and Public Affairs, Palisades, NY, United States
Effective fisheries management requires forecasting population changes. We find a negative relationship between the North Atlantic Oscillation (NAO) index and subsequently surveyed biomass and catch of Atlantic cod, Gadus morhua, off the New England coast. A 1-unit NAO increase is associated with a 17% decrease in surveyed biomass of age-1 cod the following year. This relationship persists as the cod mature, such that observed NAO can be used to forecast future adult biomass. We also document that an NAO event lowers catch for up to 15 years afterward. In contrast to forecasts by existing stock assessment models, our NAO-driven statistical model successfully hindcasts the recent collapse of New England cod fisheries following strong NAO events in 2007 and 2008 (see figure). This finding can serve as a template for forecasting other fisheries affected by climatic conditions.