The presence of ciguatoxins (CTXs) in Atlantic mackerel (Scomber scombrus) from the Canary Islands

Abstract

Ciguatoxins (CTXs) are marine toxins produced by benthic dinoflagellates of the genera Gambierdiscus and Fukuyoa, responsible for ciguatera, a globally significant food poisoning, and which has an endemic presentation in the Canary Islands. The aim of this study is to investigate the presence of CTXs during one year (September 2022 to August 2023) in the population of Atlantic mackerel (Scomber scombrus) that lives in an area between El Hierro and Tenerife, in the Canary Islands. An attempt will be made to detect ciguatoxin-like toxicity in muscle and liver samples from these fish. Eighty-four individuals were analysed. From them, muscle samples were pooled and liver samples were analysed individually. The extraction and detection of CTXs was carried out following the methods described in the official control protocol of CTX in the Canary Islands. The results showed a matrix effect in some samples, indicating variability in toxin accumulation. Although liver tends to accumulate more toxins, its matrix is less favourable for analysis, complicating toxicity assessment. In contrast, muscle proved to be a more suitable sample for CTXs detection due to its ability to accumulate toxins and its suitability for laboratory processing. This investigation provides the first evidence of the presence of CTXs in Atlantic mackerel (Scomber scombrus) from the Canary Islands. The possible risk that this result represents for public health must be clarified. The research highlights the importance of continuing to explore how these toxins are metabolised by mackerel and their potential impact on humans, especially in the context of climate change.