Spatiotemporal physical barrier analysis of southern king crab (Lithodes santolla) catch rates in Magallanes, Chilean Patagonia (2014–2020)

Abstract

Spatiotemporal patterns on fishing success and catch rates were analyzed for the southern king crab (Lithodes santolla) fishery in Chilean Patagonia (48ºS-55ºS). The analysis considered the effects of physical barriers on the spatial distribution within two complex coastal geography fishing zones. The north zone (50–54°S), close to Puerto Natales, has the more complex coastal topography, with numerous islands, archipelagos, channels, and inland sea. Instead, the south zone (55°−56°S) is relatively free of barriers. Operational data from 2014 to 2020 were obtained on board by scientific observers. The best spatiotemporal model was an opportunistic spatial pattern characterized by different yearly spatial realizations for fishing success and catch rates, with seasonal and bathymetric effects for catch rates. The higher catch rates in the north zone are probably associated with the size of crab aggregations, which tend to disperse over a wider area due to physical barriers. In contrast, the south zone has fewer physical barriers and more concentrated crab aggregations. Therefore, catch per unit effort in the southern king crab fishery should consider the effects of physical barriers on the spatial correlations and other covariables for fishing power and catchability effects.