Interaction between bottlenose dolphins (Tursiops truncatus) and artisanal fisheries in the Valencia region (Spanish Mediterranean Sea)

Abstract

Coastal waters of the Valencia region are important habitats for bottlenose dolphins, but also important fishing grounds for artisanal fisheries. No studies have been carried out here to investigate the overlap and interactions between the fishing grounds and dolphin habitat. The present study aims to assess the potential occurrence of interactions between artisanal fisheries and bottlenose dolphins in these waters. Face to face interviews were conducted to investigate for the first time artisanal fishermen's perceptions of their interactions with bottlenose dolphins.A total of 131 fishermen (40.1% of the artisanal fleet for the Valencia region) participated of research. Among the interviewed fishermen, 86.1% perceived that dolphins damaged fishing gear as they attempted to feed, and they also detected significant direct damage to fish. Of all fishermen reporting a negative interaction with bottlenose dolphins, 76.3% also reported financial loss (2907.1 ± 2512.7 €/year (100–12,000). Despite the high level of interaction with dolphins reported, fishermen do not consider bycatch to be an important threat for bottlenose dolphins. Our results show geographical differences in fishermen's perceptions of damage caused by dolphins: while dolphins were considered to be the second cause of economic loss in the southernmost ports, fishermen from the northern ports considered interaction with bottom trawl boats to be more harmful than interaction with dolphins. The more intense interaction reported by fishermen in fishing ports in the southern study area may be associated with higher presence of bottlenose dolphin in these zones. Our study provides a useful insight into fishermen's perceptions of interaction between bottlenose dolphins and artisanal fisheries in this key area for the species in the western Mediterranean Sea. It also highlights the need for future work including direct observations of interactions and damage to gather reliable data to assess the need for conservation measures.