Environmental effects on the jumbo squid fishery along Baja California’s west coast

Abstract

Since 2000, jumbo squid Dosidicus gigas catches in Baja California have increased steadily with a record catch in 2011 of 14,243,689 kg. However, little is known about stock size, distribution and seasonality, as well as the possible effects of the environment on the fishery. We tested D. gigas catches (CPUE) from 2006 to 2013 with Pacific sardine Sardinops caeruleus fishery catch data, as well as the primary productivity anomaly, sea surface temperature anomaly (SSTa), Multivariate El Nino Index (MEI), North Pacific Gyre Oscillation Index (NPGO), and price/kg using a general linear model. We also estimated D. gigas population size using two depletion models. More than 80 % of D. gigas captures for 2006–2013 occurred within 20 nmi from the coast, regardless of the fleet. We identified Salsipuedes, Soledad Bay and Vizcaino Bay as the most important D. gigas fishing grounds. D. gigas CPUE showed monthly differences, with July and August being significantly different from other months (p < 0.041; and p < 0.006, respectively). S. caeruleus and D. gigas fishing grounds overlapped geographically more than 75 %; however no correlation between catch volumes was found (p < 0.562). There was an inverse linear and significant relation between D. gigas monthly catches and the primary productivity anomaly (p < 0.021) and price/kg (p < 0.016), where a positive primary productivity anomaly and price/kg values yielded a D. gigas CPUE below 9 × 103 kg. We did not find any direct relation between SSTa, MEI, NPGO and D. gigas catches (p < 0.785; p < 0.497; and p < 0.108, respectiveley). Lack of independent fisheries data, as well as thermal tolerance and plastic life history of D. gigas, may provide an explanation on the non-apparent effect of biotical and abiotical factors in the relative abundance of D. gigas along Baja California’s west coast.