Impacts of a shift to a warm-water regime in the Gulf of California on jumbo squid (Dosidicus gigas). (18th July 2019) - Frawley, Timothy H
Abstract: Interannual oceanic oscillations, climate change, and extreme events present a significant and complex challenge to management of pelagic fisheries. In recent years, anomalous oceanographic and atmospheric conditions have been reported across the northeast Pacific, yet research results concerning the biophysical mechanisms impacting specific organisms, populations, and fishery systems remain scarce. Here we discuss trends within the Gulf of California's jumbo squid fishery in the context of relevant climate drivers, ecological dynamics, and mesoscale oceanographic processes. Following the 2009–2010 El Niño event, the jig-based fishery collapsed as squid adopted the small size-at-maturity phenotype characteristic of this species in the equatorial portion of its range. Analysis of regional sea surface temperatures and heights indicates a pronounced shift in the oceanographic trajectory of the system between the 2009–2010 and 2015–2016 El Niño events, whereas in situ hydrographic sampling reveals coincident changes in subsurface temperature and salinity. With persistently tropical oceanic conditions present across critical portions of their pelagic habitat, jumbo squid have lost access to previously productive coastal foraging zones, which in turn has limited opportunities for fishery recovery. Given the importance of jumbo squid to the region's pelagic marine foodwebs, the long-term persistence of such phenomena could have significant implications for local fisheries, economies, and livelihoods.