Study detects eight species of sharks and rays in waters of Ibiza and Formentera

A pioneering environmental DNA (eDNA) study has identified eight different species of sharks and rays in the waters around Ibiza and Formentera, four of which are classified as vulnerable or endangered.

According to IbizaPreservation, the research was promoted by GEN-GOB, the University of Oviedo, IbizaPreservation, WWF and Soldecocos, with the support of the Sant Josep de sa Talaia Town Council.

The study began in December 2024 with an oceanographic campaign. Technicians from GEN-GOB and researchers from the University of Oviedo collected seawater samples at various points along the Pityusic coastline, which were filtered on site and later analysed genetically in the laboratory. In the summer of 2025, a second campaign was carried out to compare data from two different times of the year and obtain a more complete picture of the species present.

Environmental DNA techniques made it possible to detect species through the genetic traces they leave behind in the marine environment.

“Among the species identified, the manta ray and the smooth-hound shark stand out, two emblematic species that reinforce the ecological value of our waters,” explained Laura Miralles, marine biologist and expert in marine genetics and conservation at the University of Oviedo.

According to the researchers, although both species had previously been sighted in the Pitiusas, observations were scarce. The manta ray, whose sightings were virtually non-existent just a few years ago, has begun to appear more frequently in recent times, a trend that this study confirms. They also point out that the smooth-hound shark is listed as Vulnerable on the IUCN Red List for the Mediterranean, while the manta ray is classified as Endangered.

“The study has confirmed that the Pitiusas host a diversity of elasmobranch species that deserves protection. This scientific knowledge is key to conserving them effectively,” Sobrado highlighted.

The project will continue in 2026 with a new phase focused on the satellite tagging of rays using multiparametric devices that will allow researchers to track their movements, depth, temperature and light conditions of the habitats they occupy for around 200 days. This information will be essential to “understand their mobility, migratory routes and connectivity between populations within the Balearic archipelago,” explained representatives from GEN-GOB.