2nd International Workshop on Conservation Biology

Caught in the net: prolonged partial entanglement of a bottlenose dolphin calf in fishing gear

Not scheduled

UP FAMNIT, Koper, Slovenia

Speaker

Mrs Ana Hace (Morigenos - Slovenian Marine Mammal Society)

Description

Interactions between cetaceans and fisheries are a widespread occurrence worldwide, with bycatch in fishing gear one of the main threats to these animals globally. We report on a prolonged partial entanglement of a bottlenose dolphin (Tursiops truncatus) calf in a fishing net, documented during a long-term study on bottlenose dolphin population ecology in the northern Adriatic Sea. The calf was first observed entangled in March 2014. A part of a fishing net (likely trammel net) was embedded in the anterior part of the dorsal fin, cutting into the tissue, and hanging off the sides of the dolphin. The calf, first seen in 2013 and presumed about a year old in 2014, was accompanied by its mother, with about 40 other dolphins in the group. The mobility of the animal and the depth of water in the study area precluded any potential attempts of intervention. Furthermore, it was considered that any intervention would likely be more detrimental. The calf, its mother and the rest of the group were continuously encountered in 19 sightings over the summer. The calf could apparently swim normally and its behaviour did not deviate from behaviour observed in other calves or other dolphins generally. The calf was last seen in October 2014. By this point the net was on the animal for a minimum of 203 days. At the time of last sighting, the calf was apparently still viable. However, the net has cut deeper into the dorsal fin, with the likely result of future loss of the dorsal fin. Previous data showed that bycatch is a source of calf mortality in this population. This case shows that incidental entanglement in fishing gear is not only a conservation concern, but also an animal welfare issue.