Feb 10, 2026
3 min read
A study led by the Canary Islands documents the first case in two decades of ciguatera poisoning in small fish and improves the island's health surveillance.
Researchers from the University of La Laguna and the General Directorate of Public Health of the Government of the Canary Islands have documented the first case in two decades of ciguatera poisoning related to a fish weighing only two kilograms, a finding that violates one of the biological principles that until now guides the health control of the islands.
This study examines the development of ciguatoxin in the Canary Islands between 2008 and 2025 and is described by its authors as a scientific example, showing that this toxin can reach special levels in small samples, which until now have been considered special.
The study focuses on an outbreak in the islands in June 2025 after consumption of picuta (Sphyraena viridensis) purchased at a supermarket.The fish is not subject to the current mandatory control of weight, because the regulations implemented in the Canary Islands set a minimum limit that cannot be reached in this regard.
According to Alvaro Torres, a researcher at the Epidemiology and Prevention Service of the University of La Laguna and the General Directorate of Public Health, the accumulation of the toxin follows a known pattern in the Canary Islands, similar to other pollutants such as mercury.
"Toxins build up, they're not cleaned out. It's like algae: the bigger the fish, the more fish, and the bigger the fish, the more toxic it is," Torres said."Therefore, the discovery of related toxins in a fish weighing only two kilograms is an unusual event in the context of the Canary Islands."
This fact motivated the publication of this study, because, as emphasized by the authors, what is happening in the Canary Islands does not reflect anything common or patterns observed over decades of epidemiological surveillance.
Canary Islands and a discovery that challenges biological norms
Despite the relevance of the discovery, the researchers wanted to send a clear message of peace to the population of the Canary Islands.Torres stressed that food chain safety remains high and that current control systems work properly.
"We can continue to rely completely on the system we have," said the researcher, who warned that the possibility of finding fish with dangerous toxin levels outside of normal control in the Canary Islands is very low.
In fact, if this type of shock is common in small fish, the incidence of poisoning in the Canary Islands would be much higher, which is not reflected in the health control data.The numbers collected over almost two decades refute any widespread risk scenario.
The protocols in force in the Canary Islands stipulate mandatory inspections for specific species such as ambergris and ruchesvec.In addition, the system is designed to dynamically adjust, allowing new species to be added or the minimum control weight to be reduced as scientific evidence warrants.
Difficulty in diagnosis and characteristic symptoms
This research also focuses on one of the great challenges related to ciguatera in the Canary Islands: clinical diagnosis.The authors explain that the symptoms can be very unspecific and easily confused with other common pathologies.
In an analysis of the 2025 outbreak in the Canary Islands, an affected person spent almost a month visiting various medical services without receiving a clear diagnosis until he was treated by a specialist who recognized the neurological symptoms of Ciguatera.
Therefore, this study shows the need to train emergency workers in the Canary Islands to continue to suspect patients with gastrointestinal symptoms accompanied by paresthesia or abnormal heat after eating fish.
Canary Islands, European reference for observing ciguatera
Such comprehensive monitoring is possible because the Canary Islands are in first place in this matter.Currently, the archipelago is the only region in Europe where ciguatera is actively monitored from the point of view of human health.
A total of 28 outbreaks were detected in the Canary Islands during the analyzed period, of which only four were caused by species not initially included in the surveillance program.
This work is the result of an interdisciplinary effort coordinated by the Epidemiological Service and the Food Safety Service of the Government of the Canary Islands, with the University Institute of Animal Health and Food Safety of the University of Las Palmas de Gran Canaria, responsible for the toxicological analysis.
The author confirms that the process of updating the protocol in the Canary Islands is continuous and is fed directly from newly detected cases. Thus, it completes a system that remains a reference inside and outside the archipelago.
