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Cetaceans have great environmental relevance. Its species are located at the top of food webs and have a role as species of interest for conservation, in addition to functioning as sentinels of the health of marine ecosystems.

In the Mediterranean, 22 species of cetaceans have been reported, of which 8 have regular populations: the fin whale, the sperm whale, the pilot whale, the risso, the Cuvier’s beaked whale, the killer whale, the bottlenose dolphin, the common dolphin and the striped dolphin. These species, which enjoy different protection figures, are usually present in the waters included in the Marine Protected Area “Mediterranean Cetacean Migration Corridor“, which runs between the Catalan and Valencian coasts, and the Balearic archipelago.

This project has worked on research on the distribution and abundance of cetacean populations in the southern area of this protected area and on the assessment of the main anthropogenic threats, such as maritime traffic and interaction with fisheries, with the aim of providing baseline information to establish future management and dynamic management measures.

The general objective of the project has been to assess the state of conservation and the impact of human activities on cetacean populations in the Spanish Mediterranean.

The specific objectives were as follows:

• To review and contrast the current conservation status of cetaceans present in the Spanish Mediterranean.
• To determine the distribution and abundance of the different cetacean species in the southern half of the Mediterranean Cetacean Migration Corridor.
• To determine the main anthropogenic threats affecting the different cetacean populations in the south of the Mediterranean Cetacean Migration Corridor.
• Disseminate the results obtained to promote regulatory measures and raise awareness of the problem among the authorities involved and society in general.

• Bibliographic review of 200 scientific articles related to the abundance, distribution and conservation status of the 8 main species of cetaceans in the Mediterranean, published in recent years.
• Review of the reports of the autonomous communities of the Balearic Islands and the Valencian Community, of the Mediterranean Cetacean Stranding Database (MEDACES and BEVACET), as well as of NGOs and international organizations, such as ACCOBAMS (especially in its Survey Initiative), and the International Whaling Commission. With this, it has been possible to collect data on sightings, strandings, locations and other information from the last 40 years for each species under study.
• Obtaining own data through aerial and boat censuses to add some current data on the abundance and diversity of cetaceans in the study area. In the flights, sightings of cetaceans, turtles and other species, group size, behaviour and environmental parameters were recorded, while in boat censuses they are used to study aspects of the biology of the species, presence of offspring, relationship with other species, etc. The main results of these censuses have been reflected in a database and a map of diversity and abundance of eight species of cetaceans observed, and three maps of the distribution of strandings were also prepared: one for bottlenose dolphin (Tursiops truncatus), another for striped dolphin (Stenella coeruleoalba) and a joint map of the strandings of nine other species.
• Evaluation of bycatch as one of the main anthropogenic threats affecting the different cetacean populations, through surveys of fishermen, visits to fishermen’s guilds and fishing ports and the study of cases of interaction with fisheries based on cetacean stranding data. With the information obtained, maps of overlap between different species of cetaceans have been drawn up) and the two fishing gears with the largest fleet in the ports of the Valencian Community: bottom trawling and traditional fishing.
• Evaluation of maritime traffic data to know the routes of vessels transporting people and goods and their passage through areas of concentration of cetacean populations in the study area to determine the risk of collision between species and vessels.
• Holding 4 days of awareness for agents involved in the cities of Mallorca, Valencia, Ibiza and Denia, with the aim of publicizing the results of the project and raising awareness of the problem among the authorities and society in general. It is estimated that approximately a total of 57,500 people have visited the exhibition, adding the 4 cities.
• Dissemination of results to the agents involved, with the holding of meetings with the Valencian Government and the Balearic Government, the organisation of a sustainable fishing awards ceremony and visits to fishermen in ports, where informative leaflets were distributed.
• Dissemination of results to university students and the general public, through talks at the Spring University of Alzira and at the University of Valencia to students of the Bachelor’s Degree in Environment and the Master’s Degree in Biodiversity, the holding of workshops on cetaceans in the University’s Science Park and the publication of two articles in the informative magazine ACCOBAMBS.
• Dissemination of results to a specialized public through the presentation of the project at two national congresses, the XXIV Biennial of the Royal Spanish Society of Natural History, held in Valencia and the XII Congress of the Spanish Society of Cetaceans (SEC). In addition, a scientific paper was published in the scientific journal Frontiers in Marine Sciences.
• Dissemination of results to public authorities, which included the preparation of a report detailing the current situation of cetaceans and maritime traffic in the Mediterranean Sea, as well as the methodology used by the entity to assess the main anthropogenic impacts suffered by cetaceans: bycatch and collisions with vessels. This report was submitted to MITECO, the Biodiversity Service and Fisheries Service of the Ministry of Agriculture, Rural Development, Climate Emergency and Ecological Transition of the Generalitat Valenciana, as well as to the General Directorate of Natural Spaces and Biodiversity of the Ministry of Environment and Territory of the Government of the Balearic Islands.
• Dissemination and communication of the project through two telematic talks in the 2020 and 2021 editions of World Oceans Day, with 109 and 168 attendees respectively. In addition, a website of its own was set up for the project, where the objectives, the team and the actions of the project are exposed. On the other hand, a press release was prepared to be disseminated in various media and interviews were participated in different media and in the RTVE informative program “The Adventure of Knowledge”.

Thanks to this project, a study of the main threats affecting the conservation of cetaceans in the south of the Mediterranean Cetacean Migration Corridor has been carried out: bycatch and collision with boats.

On the one hand, the accidental catches of cetaceans by the fishing fleet operating in that area have been estimated, by carrying out surveys of skippers and fishermen. The species most accidentally caught by trawling and purse seine fishing are the bottlenose dolphin and the striped dolphin, the case of the bottlenose dolphin being more worrying, as it has a much smaller population and is considered a vulnerable species. In any case, according to the entity, both species must be considered in management plans to ensure their conservation and the sustainability of their populations , taking into account fishing activities in waters surrounding marine protected areas, such as the Mediterranean Cetacean Migration Corridor.

Regarding the density of maritime traffic and its consequent collision with boats, risk has been detected for all the species studied in all seasons, but the Three areas of greatest risk: the south of the study area for fin whales in summer, pilot whales in summer and spring and striped dolphins in spring, summer and autumn; the coasts of the provinces of Valencia and Alicante, with a high risk of collision for coastal cetacean species such as the bottlenose dolphin and striped dolphin; and the northern area of Castellón with a high risk of collision for the fin whale and the bottlenose dolphin.

In addition, the entity has carried out awareness-raising and dissemination actions aimed at different audiences (general public, university students, specialised public, agents involved, and public authorities) and carried out in different formats, such as conferences, colloquiums, meetings and exhibitions.