An international study in which the Centro de Estudios Ambientales de Cienfuegos (CEAC) confirmed the presence of several species of benthic microalgae from the genus Gambierdiscus along the coast of Havana, some associated with the production of ciguatoxins. Among the main findings is the first identification of Gambierdiscus australes in both Cuban waters and the Caribbean Sea.
The research, published in August 2026 in the scientific journal ACS Environmental Au, identified six species of Gambierdiscus from 35 isolates obtained at two locations on the Havana coast. The analyses also confirmed the presence of C-CTX5 in a Cuban strain of Gambierdiscus silvae, providing new evidence regarding the origin of ciguatoxins in the Caribbean.
The CEAC publicly released the results on Tuesday, September 15, and Prensa Latina reported on the study the following day.
The scientific team, which is multidisciplinary and international, isolated and analyzed 35 monoclonal strains of benthic microalgae obtained from samples collected along the coast of Havana.
A total of six species of the genus Gambierdiscus were identified in those samples, among which Gambierdiscus caribaeus was found to be the most abundant, according to the report from Prensa Latina.
One of the most significant findings was the confirmation, through biological assays and mass spectrometry, of the production of ciguatoxin C-CTX5 by a Cuban strain of Gambierdiscus silvae. According to the state media, this evidence "reinforces the role of this species as a significant source of ciguatoxins in the region." This toxin can act as a precursor to the ciguatoxins C-CTX1 and C-CTX2, which are the predominant ones found in ciguatoxic fish from the Caribbean.
The chemical analyses also revealed the presence of other metabolites: gambierone and 44-methylgambierone. Prensa Latina noted that these results "broaden understanding of the biodiversity of microalgae in the Caribbean."
In the study, alongside CEAC, specialists from the Institute of Agricultural Research and Technology and the Rovira i Virgili University from Spain participated, as well as from the Scientific Research Center and Higher Education of Ensenada (CICESE) in Mexico. The research was part of the CIGUATOX project — "Diversity, distribution, and toxicity of Gambierdiscus spp. and Fukuyoa spp. in Cuba" — funded by the Nuclear Energy Agency and Advanced Technologies (AENTA), with additional support from the Spanish programs BiOCEANsing and CIGUAADAPT, and the European project BlueShellfish.
Ciguatera is a foodborne illness endemic to the Caribbean, primarily caused by the consumption of fish that accumulate ciguatoxins originally produced by benthic microalgae of genera such as Gambierdiscus and Fukuyoa. In Cuba, the disease has a long documented history.
An epidemiological study conducted over 16 years in the province of Ciego de Ávila recorded, between 1983 and 1998, 46 outbreaks with 305 cases, without any fatalities; nearly half of the outbreaks (47.8%) occurred between July and September. Another study, conducted with 227 patients treated in Havana between 1999 and 2005, identified the barracuda as the species most frequently associated with poisoning, with 74 cases.
Cuban regulations prohibit or restrict, depending on the species and weight, the capture, landing, and commercialization of various potentially toxic fish, including the picúa or barracuda, the coronados, the platform jurel, and certain species of groupers and snappers. Historically, these regulations have contributed to reducing incidents related to the formal fishing circuit, although controlling ciguatera requires maintaining epidemiological and health surveillance, particularly regarding unauthorized captures and sales.
The symptoms of ciguatera range from gastrointestinal manifestations—nausea, vomiting, diarrhea, and abdominal pain—to neurological issues such as tingling, numbness, and muscle weakness, as well as cardiovascular disturbances. The Cuban healthcare context in 2026 exacerbates the concern: in August, 52 individuals were affected by mass food poisoning in Santiago de Cuba, and this Friday another outbreak was reported in Matanzas.
The CEAC, based in Cienfuegos, is a Cuban institution dedicated to environmental research with an important line of investigation on marine-coastal ecosystems and has been designated in 2024 by the International Atomic Energy Agency (IAEA) as a collaborating center in Cuba for coastal and marine health issues.
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