Mass stranding of melon headed whales

Despite the efforts of all the people who volunteered their time to save the melon-headed whales that were stranded, the majority of the animals came back to the shore. Since the event, Bios CV, the Ministry of Agriculture and Environment, and the City Council have been following the situation and report that a total of 136 out of the 164 whales were found dead on Altar beach.

Bios CV took samples and collected biometric data from 50 whales, and 4 are being kept frozen in the CMBV facilities. To prevent the possible spread of disease, the remaining carcases are being buried by the MAA-BV Delegation. In collaboration with the MARCET, a European project, biologists from the Institute of Animal Health (USA), and the University of Las Palmas (Gran Canaria) are travelling to Boa Vista to perform a necropsy on the carcases in an attempt to explain why this happened. They will also take the opportunity to train local scientists for the future.

During a morning turtle patrol, at around 5:30 am on September 24, 2019, 17 melon-headed whales were found on the beach near Bofareira on the coast of Boa Vista. The staff and volunteers of Bios CV were immediately called for help. By 7:00 am 164 individuals were stranded on the beach.

Through the course of the day, approximately 100 people from all over the island came to help return these animals to the sea including members of the ministry of agriculture and environment, the national police, maritime authorities, fishing inspectors, the NGOs Fundaçao Tartaruga, Natura 2000, Bios CV, and Maralliance, tour companies and their clients, and community members from Bofareira, Norte, and Sal Rei. Unfortunately, the rescue mission was unsuccessful, as most of the cetaceans that were returned to the sea-washed back up. Final mortality has yet to be determined.

Melon-headed whales (Peponocephala Electra) are highly social members of the dolphin family that live in groups of hundreds of individuals. They are known not to abandon their group members, and this may be the reason that, so many, followed their companions onto the beach. Along with pollution and interactions with fishing vessels, a major threat to this species is oceanic noise. Loud noises cause them to flee areas that are important to their survival, and has also been demonstrated to drive groups to strand and ultimately death. This is unfortunately not a unique event on Boa Vista, yet the cause of the stranding is still unknown.