European Ocean Biodiversity Information System

Since January 2018 data were collected for monitoring cetacean populations of the Strait of Gibraltar using ferries as platform of observation. The monitoring program was build-up in the area of study by the University of Cádiz (https://www.uca.es) and Ecolocaliza (https://ecolocaliza.com), thanks to the support of the Fundació Baleària (http://fundaciobalearia.org.). The cetacean monitoring programme of the Strait is part of the international Fixed Line Transect Mediterranean monitoring Network (FLT Med Network - http://www.isprambiente.gov.it/it/temi/biodiversita/lispra-e-la-biodiversita/attivita-e-progetti/flt-mediterranean-monitoring-network-marine-species-and-threats-en-en). Data were collected following the monitoring protocol of the FLT Med Network, from dedicated Marine Mammal Observers (MMOs) placed on both sides of command deck of ferries along the whole trip. Each MMO covers an angle of 130° from the bow to the stern. The back of the ship was checked randomly to avoid double counting of sightings. The animals were not approached but distance and angle from the track line were recorded. Sighting data include group size estimation (e.g., minimum, maximum), age class and behaviour. Also maritime traffic sampling were recorded, that includes the number of vessels during the sightings and every hour along the trip. Data were gathered on board of the ferries routing between Algeciras city (Spain) and the harbours of Tanger-Med (Morocco) and Ceuta (Spain). Five surveys per season were undertaken during the year for both routes depending on sea conditions and platforms availability, with a minimum of one survey per route each month. In the Strait of Gibraltar were monitored the cetacean populations of the following species: short-beaked common dolphin (Delphinus delphis), striped dolphin (Stenella coeruleoalba), bottlenose dolphin (Tursiops truncatus), long-finned pilot whale (Globicephala melas), sperm whale (Physeter macrocephalus), fin whale (Balaenoptera physalus) and killer whale (Orcinus orca). Data were also collected also on other species of macrofauna, for instance: loggerhead sea turtle and ocean sunfish. The dataset contains effort data (e.g., meteorological conditions) and sighting data (105 of cetaceans and 9 of other macrofauna organisms). Dataset shared with EMODnet includes since January to December 2018. This monitoring program is still operative and it is manage by the Association Nereide (https://en.nereide.org/projects-ferries).