Ciguatera fish poisoning (CFP) occurs mainly when humans ingest finfish contaminated with ciguatoxins (CTXs). The complexity and variability of such toxins have made it difficult to develop reliable methods to routinely monitor CFP with specificity and sensitivity. This review aims to describe the methodologies available for CTX detection, including those based on the toxicological, biochemical, chemical, and pharmaceutical properties of CTXs. Selecting any of these methodological approaches for routine monitoring of ciguatera may be dependent upon the applicability of the method. However, identifying a reference validation method for CTXs is a critical and urgent issue, and is dependent upon the availability of certified CTX standards and the coordinated action of laboratories. Reports of CFP cases in European hospitals have been described in several countries, and are mostly due to travel to CFP endemic areas. Additionally, the recent detection of the CTX-producing tropical genus Gambierdiscus in the eastern Atlantic Ocean of the northern hemisphere and in the Mediterranean Sea, as well as the confirmation of CFP in the Canary Islands and possibly in Madeira, constitute other reasons to study the onset of CFP in Europe [1]. The question of the possible contribution of climate change to the distribution of toxin-producing microalgae and ciguateric fish is raised. The impact of ciguatera onset on European Union (EU) policies will be discussed with respect to EU regulations on marine toxins in seafood. Critical analysis and availability of methodologies for CTX determination is required for a rapid response to suspected CFP cases and to conduct sound CFP risk analysis.

Cyst studies carried out in 2002–2003 on Mediterranean Sea sediment from seven different sites along the Catalan and Balearic coasts (Western Mediterranean) revealed a higher diversity of Alexandrium species in the region than was previously known. The cysts of eight species of the toxigenic, marine dinoflagellate genus Alexandrium are described, and some, such as A. kutnerae, A. margalefi, A. peruvianum and A. pseudogoniaulax, are reported from the area for the first time. This is also the first record of resting cysts of A. taylori in Mediterranean sediment, and the first description known to date of resting cysts for A. kutnerae and A. peruvianum. All the cysts were characterized by a smooth wall except for the paratabulated cyst of A. pseudogoniaulax, and most of them had a prominent yellow/orange accumulation body. Nevertheless, we have also detected an unparatabulated cyst of A. pseudogoniaulax, both from the sediment and in cultures. The cyst of A. kutnerae had a roughly cylindrical shape with rounded ends which makes it impossible to distinguish from resting cysts of A. tamarense and A. catenella, while the flattened round cysts of A. peruvianum were very similar to those of A. taylori. The cyst concentration data revealed A. catenella and A. minutum to be the most abundant cysts in the region, and they were detected in semi-enclosed waters, such as harbours. This highlights the importance of water exchange in the accumulation of cyst beds of these species, which has already been reported in the region by other authors for A. minutum. This paper contributes to the biogeographic distribution of some Alexandrium species, such as A. kutneare, A. margalefi, A. peruvianum and A. pseudogoniaulax, which have been reported only infrequently in a global context.