In the coasts of Andalusia, especially in Cadiz and Huelva, resides what is probably the last stable population in Europe of giant guitarfish (Glaucostegus cemiculus). This species of cartilaginous ray, related to sharks, has disappeared from most of its original range, stubbornly resisting extinction in a small corner of southern Spain. It is currently critically endangered. according to the International Union for Conservation of Nature (IUCN), which implies that its future essentially depends on the conservation efforts carried out there.
For decades, this peculiar animal, which can grow up to two and a half meters long and weigh more than 30 kilos, was a relatively common sight on the Atlantic coast and in areas of the Mediterranean. Nowadays, seeing a guitarrón is an extraordinary event.; accidental fishing, the transformation and reduction of their habitats, and human pressure have been determining factors in their alarming decline. Their slow reproductive rate, with gestations of up to nine months, makes the species' recovery particularly difficult even if the threats disappear.
Glaucostegus Project: International Collaboration and Citizen Science
Faced with this situation, the Glaucostegus Project It has become a European benchmark for the study and protection of the giant guitarfish. A consortium of entities such as the Oceanogràfic Foundation, the Azul Marino Foundation, the Seville Aquarium and the LAMNA Association, in addition to universities and public organizations, have joined forces with scientists, institutions, and ordinary citizens to address this challenge.
Under the coordination of the doctor Jaime PenadésThe project has established the systematic collection of scientific data and citizen observations since 2018, the year in which Ángel Benítez promoted the involvement of recreational fishermen and volunteers in the area. Through photos, videos and data associated with accidental captures (date, location, fishing method), more than 80 confirmed sightings have been collected in recent years, which is essential to better understand and protect the species.
The application of simple and effective protocols has allowed, in addition to documenting the presence of the guitarfish, confirm its reproduction in Andalusian waters (including newborn specimens) and detect poaching hotspots; from cases of specimens thrown in the trash on beaches like Valdelagrana to stories of illegal sales in restaurants.
Scientific campaigns and the hope of the ex situ reproduction plan
Fieldwork is not limited to just collecting testimonies. Scientific sampling campaigns have intensified our understanding of the species' biology and status. A notable example was the activity on Valdelagrana Beach in late May 2025, where more than 40 researchers examined 33 guitarrones, both juveniles and adults, following protocols that minimize stress and ensure animal welfare.
During these campaigns, data are collected DNA and blood samples, measurements, and biometric studies to assess the population's status and detect potential health or genetic risks. The entire process is authorized by the authorities (MITECO, the Andalusian Regional Government, and the Doñana Biological Station), which provides institutional support for the initiative.
One of the most promising avenues being investigated is the ex situ reproduction planThis involves genetically comparing specimens from the wild with those found in the zoological collections of some of the most important aquariums on the Iberian Peninsula. The objective is twofold: to evaluate genetic diversity for potential captive breeding programs, and to prepare for a future reintroduction of the guitarfish in areas where it has now disappeared but is considered safe.
An emblematic species of marine conservation in Europe
The guitarrón, besides being an icon of Andalusian biodiversity, is becoming an international symbol of the urgency of protecting endangered marine speciesThe collaborative work of researchers, NGOs, recreational fishermen, and government agencies demonstrates that, although the situation is complicated, there are still ways to prevent the extinction of this unique animal.
The key lies in the collaboration between civil society and the scientific sectorThanks to this collective involvement, significant progress has been made in just a few years, paving the way for new conservation strategies and a shift in public thinking regarding the ecological and heritage value of a species that, until recently, went unnoticed by most.
Although the guitarrón remains in an extremely delicate situation and faces risks such as illegal fishing, habitat destruction and pressure against its conservation, Recent efforts provide cause for optimismThe Andalusian experience demonstrates that it is still possible to reverse the fate of endangered species if we act quickly, collaboratively, and with a commitment to biodiversity.
