IMIS

The butterfly ray (Gymnura altavela) is an elasmobranch species (Order: Myliobatiformes, Family: Gymnuridae) classified as endangered on the IUCN Red List and protected at the state level in the LESPRE (MITECO, Spain). This species was considered rare in the Balearic Islands and is currently included in the Balearic Islands’ Catalogue of Threatened Species. The main threats it faces include commercial and accidental fishing, as well as habitat degradation. Since 2021, the RAJIBAL Project has been carried out along the coast of Mallorca, within the Balearic Sea, with the aim of assessing the status of G. altavela populations. Specifically, the project’s goals include studying the species' spatial and temporal movement patterns, as well as its genetic variability. The first captures of G. altavela occurred in July 2024 at two sites of interest, which were identified based on sightings recorded through citizen science: El Toro and Malgrats Islands Marine Reserve, and the Migjorn Marine Reserve. In both areas, the specimens were tagged with acoustic transmitters and floy tag visual tags, biometric and genetic samples were taken, and sex was identified. In the El Toro and Malgrats Islands Marine Reserve, the animals were captured using a containment device during scuba dives and tagged onboard a vessel, while in Migjorn Marine Reserve the capture was done with a hand net during freediving, and the specimens were tagged on land. To date, 16 individuals have been tagged: 3 in El Toro and Malgrats Islands and 13 in Migjorn. Tracking of these specimens is expected to provide information on the species’ distribution in Mallorca, its movement patterns, seasonality, and possible aggregation areas. This project is crucial as it uses advanced technologies to generate valuable data that contributes to the study, stewardship, and conservation of G. altavela, aiding in its long-term preservation in a context of climate change and increasing environmental challenges.