Population dynamics of the jumbo squid (Dosidicus gigas) in the 2002–2008 fishing seasons off Guaymas, Mexico

We report on the population dynamics of Dosidicus gigas off Guaymas from the 2002–2003 to 2007–2008 fishing seasons. The study was supported by the catch-at-length data of the commercial fleets. The results showed a large variation in recruitment because during some fishing seasons the recruitment was poor. This condition in the population may also be impacted by migration, a new distribution of jumbo squid in the eastern North Pacific, or the changes in the California current. We identified a pattern in the variability of recruitment. Warmer waters caused by the El Niño conditions in the California current are coincident with low recruitment. Cooler waters identified with negative anomalies in the sea surface temperature caused by La Niña were related to high recruitment. Our time-series showed a reduction in recruits and a fall in the mean biomass. For the jumbo squid fishery off Guaymas, recruitment determines trends of biomass over time. Our results also showed that for all fishing seasons the proportional escapement was between 59% and 89%, which was higher than the target level of 40%. Consequently, the harvest of jumbo squid is less than the optimum level.