Toxic Microalgae Detected Along Murcia Coast

The Polytechnic University of Cartagena has been tracking potentially toxic microalgae along Murcia’s Mediterranean coast after researchers identified Ostreopsis and Gambierdiscus in coastal samples, according to university and local media reports. The findings are part of LEVABENTOX, a project led by the Institute of Agrifood Research and Technology, or IRTA, and carried out with UPCT researchers at beaches between northern Almería and La Manga, as well as Cabo Tiñoso Marine Reserve. Researchers said there is no immediate public-health alert and no toxins have been detected in fish so far. The work has nonetheless prompted closer monitoring of waters used for fishing and bathing as sampling continues into 2026. ### Which organisms have researchers found off Murcia? UPCT said on June 30, 2025 that microscopy results from algae samples collected on beaches along southern Murcia’s coast confirmed the presence of potentially toxic benthic dinoflagellates in fishing and recreational areas. The university said researchers found Ostreopsis, a microscopic algae genus that lives in shallow waters, and also detected smaller quantities of Gambierdiscus. (upct.es) Murcia Today reported on May 19, 2026 that the research has since confirmed those genera at various points along the Mediterranean coastline in southeast Spain. The outlet said the work has been extended into 2026 for further analysis of how the populations evolve. ### Why are scientists watching Ostreopsis so closely? (upct.es) Murcia Today said some sampled areas recorded Ostreopsis concentrations of up to 500,000 cells per gram of macroalgae. The report said the species attaches to rocks and seaweed and tends to proliferate in shallow water during the warmest months of the year. (murciatoday.com) UPCT researcher Olga Carnicer said France, Italy and Catalonia already run specific monitoring programs for these species in bathing waters. UPCT said toxic species within the Ostreopsis genus can cause coughing, fever, skin irritation and mild respiratory problems, and Murcia Today said exposure can occur through sea spray or direct contact when concentrations are high. (murciatoday.com) ### Why does Gambierdiscus draw concern from food-safety authorities? UPCT researcher Olga Carnicer said the team also found Gambierdiscus dinoflagellates, some species of which produce ciguatoxins that can cause food poisoning after fish consume the microalgae. The university said the project is assessing the risk posed by possible bioaccumulation of toxins in the food chain. (upct.es) The European Food Safety Authority says ciguatoxins are produced by Gambierdiscus species and can enter the food chain through fish and other seafood. EFSA says ciguatera fish poisoning is the most common marine biotoxin food poisoning worldwide and that Gambierdiscus has been found in Mediterranean islands including Crete, Cyprus and the Balearics. ### Where is the monitoring taking place? (upct.es) UPCT said samples are being taken at 15 beaches between northern Almería and La Manga, along with the Cabo Tiñoso Marine Reserve. The university said researchers are working with the fishing sector on sample collection and culturing species for morphological, molecular and toxin characterization. (efsa.europa.eu) Murcia Today said higher concentrations of Ostreopsis have been detected in southern coastal areas of Murcia and in northern Almería. The report added that researchers consider the species present across much of the Mediterranean, even as local concentrations vary. ### What have officials and researchers said about immediate risks? (upct.es) Murcia Today reported on May 19, 2026 that researchers said there is currently no immediate risk to public health and that no toxins have been detected in fish. The report said the current response is focused on closer observation rather than beach closures or fishing bans. (murciatoday.com) The LEVABENTOX project is being carried out with support from Fundación Biodiversidad under Spain’s Ministry for the Ecological Transition and the Demographic Challenge and is co-financed by the European Maritime, Fisheries and Aquaculture Fund, UPCT said. The next step is continued sampling and toxin analysis in 2026 as researchers track whether the populations expand during the warmer months. (upct.es) (murciatoday.com)