Line of action:

Status:

Execution date:

General Objective:

To elucidate the possible interactions between the bottlenose dolphin and artisanal fishing gear (trammel and moorish) and purse seine fishing in several marine protected areas in the provinces of Alicante, Murcia, Almeria and Malaga. It will seek to determine the impact of such interactions on both bottlenose dolphin populations and fishermen who may be affected, and analyse whether there are differences depending on the fishing gear.

To this end, navigation campaigns will be combined in the areas considered to take data in situ, making use of the photoidentification of dorsal fins, with the deployment of omnidirectional hydrophones in the fishing gear itself, as well as surveys at the foot of the fish market to the fishermen themselves. The results obtained will allow proposals for management measures aimed at achieving the compatibility of the presence of bottlenose dolphins with traditional fishing economic activity.

Specific objectives:

1. To determine the positive or negative effects of artisanal fishing gear (trammel and moorish) on the bottlenose dolphin.
2. To determine the possible effects on artisanal fisheries (trammel and moorish fisheries) and purse seine fisheries, derived from the interaction of bottlenose dolphins in marine protected areas and adjacent areas.
3. Propose management measures for bottlenose dolphins based on the results obtained.
4. Involve artisanal fishermen in the conservation of these species.
5. To make marine species and protected areas known to the local population.

The project has improved the knowledge of the bottlenose dolphin. Between April and December, four navigation campaigns were carried out on board the motorsailer Else, in which 40 people participated to make a bottlenose dolphin photo-identification catalogue, update the existing information and compare it with that of previous years. Distance Sampling methodology was used to complete the population dynamics data with results on distribution and density, but not enough sightings were observed to be able to run the models.

To estimate abundance, mark-recapture models were designed from the dorsal fin photoidentification data. 9,337 images were analyzed, corresponding to sightings between 2016 and 2019. The low number of sightings did not allow for robust estimates.

The main activities carried out and conclusions were:

• Of the 699 individuals considered in the catalog, only 22 (3.1%) were observed interacting with minor gear networks. Meanwhile, 274 (39.2 %) were observed in interaction with one or more of the fishing gears; 157 (22.5%) in interaction with trawlers and 131 (18.7%) with aquaculture farms. Only one was observed in interaction with the three types of gear and always in the northern zone between 2010 and 2019.

• Individuals interacting with fisheries have been observed in 9 of the 12 social groups. Three individuals sighted in interaction with gillnet fishing gear are considered key in the social network, as they have ties to a large number of individuals and belong to two different social groups.

• A hydrophone was placed in artisanal gillnets in the three study areas. The behavior of dolphin pods with respect to interactions with the nets was not homogeneous. With this experience, limits are established to the capacity of hydrophones to record interactions.

• 44 surveys were carried out in five fish markets: Santa Pola, San Pedro del Pinatar, Cartagena, Adra and Caleta de Vélez. 64% of artisanal vessels were reached. 93% of those surveyed have had interaction with the species at some point and more than half during 2019. 95% of these fishermen identify the bottlenose dolphin as the dolphin species with the most interaction – the breaks caused by dolphins are characteristic of tearing off pieces of net next to the fish, which causes them to be expensive to repair and complicated to prevent.

• A section was prepared on the ANSE website with exclusive content of the project in which the news generated during its execution was collected. In addition, news of the project was published on the association’s social networks (Facebook, Twitter, YouTube) and training courses were held, with the participation of 78 people.

• Three meetings were held with three brotherhoods in the study area. The objective was to inform the participants of the data obtained and the preliminary results. Questions were also raised aimed at knowing the most appropriate management measures to deal with the problems they suffer from interactions with the bottlenose dolphin.

The information obtained has allowed us to improve our knowledge about interactions with bottlenose dolphins. The number of sightings and the acoustic data do not allow some of the estimates expected in Andalusia to be made. However, the acoustic data from Cabo de Palos, together with the sharing of the sightings produced during the project with the catalogue of dorsal fins obtained by ANSE in the last 20 years, in addition to the surveys and information from previous projects, provide a basis for proposing management measures in the context of the study area.