Living on the edge: Overlap between a marine predator's habitat use and fisheries in the Northeast Atlantic waters (NW Spain)

The impact of commercial fisheries on marine top predators is currently the focus of considerable international concern. In spite of the recognition of the competition between fisheries and marine predators for the same resources, few comprehensive assessments of the level of overlap between marine predators and fisheries have been conducted. Data from 273 daily boat surveys over a period of 4 years along the northwestern coast of Spain were used to assess the environmental, topographic, and anthropogenic correlates of habitat use and relative density of short-beaked common dolphins. Moreover, the degree of vulnerability of this marine top predator to coastal fisheries was assessed by identifying the type of fisheries associated with the presence of common dolphins. Our results reported that common dolphin presents a fine-scale pattern of habitat use, with an unequal use of available habitat and varying relative abundance, which was mostly related to the variation in environmental, topographic, and anthropogenic variables. The high occurrence of common dolphins in zones characterized by a high bottom trawl fishing pressure was indirectly linked to the susceptibility of these marine predators to fishing activities. These findings can be used as a relevant indicator of the degree of vulnerability of common dolphins to human pressure providing comprehensive information on which to base conservation and management strategies.