RESUMEN
Diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTX) produced by endemic species of the genus Dinophysis, mainly D. acuta and D. acuminata, pose a big threat to public health, artisanal fisheries and the aquaculture industry in Southern Chile. This work reports the first detection of lipophilic toxins, including pectenotoxin-2 (PTX-2) and gymnodimine-A (GYM-A), in hard razor clam (Tagelus dombeii) associated with an unprecedented spring bloom -38.4â¯×â¯103 cells L-1 in integrated hose sampler (0-10â¯m) - of Dinophysis acuminata in coastal waters of central Chile. The socio-economic challenges to small-scale fisheries are discussed. The study points to the pressing need for sound policies to face unexpected HAB event, probably due to biogeographical expansions, with a focus on fisheries management, participation of stakeholders, and development of adaptive capacities.
Asunto(s)
Dinoflagelados , Toxinas Marinas , Intoxicación por Mariscos , Animales , Chile , Mariscos/análisisRESUMEN
Azaspiracids (AZA) are the most recently discovered group of lipophilic marine biotoxins of microalgal origin, and associated with human incidents of shellfish poisoning. They are produced by a few species of Amphidomataceae, but diversity and occurrence of the small-sized dinophytes remain poorly explored for many regions of the world. In order to analyze the presence and importance of Amphidomataceae in a highly productive area of Argentinean coastal waters (El Rincón area, SW Atlantic), a scientific cruise was performed in 2015 to sample the early spring bloom. In a multi-method approach, light microscopy was combined with real-time PCR molecular detection of Amphidomataceae, with chemical analysis of AZA, and with the establishment and characterization of amphidomatacean strains. Both light microscopy and PCR revealed that Amphidomataceae were widely present in spring plankton communities along the El Rincón area. They were particularly abundant offshore at the shelf front, reaching peak densities of 2.8 × 105 cells L-1, but no AZA were detected in field samples. In total, 31 new strains were determined as Az. dalianense and Az. spinosum, respectively. All Az. dalianense were non-toxigenic and shared the same rRNA sequences. The large majority of the new Az. spinosum strains revealed for the first time the presence of a non-toxigenic ribotype of this species, which is otherwise the most important AZA producer in European waters. One of the new Az. spinosum strains, with a particular slender shape and some other morphological peculiarities, clustered with toxigenic strains of Az. spinosum from Norway and, exceptionally for the species, produced only AZA-2 but not AZA-1. Results indicate a wide diversity within Az. spinosum, both in terms of sequence data and toxin profiles, which also will affect the qualitative and quantitative performance of the specific qPCR assay for this species. Overall, the new data provide a more differentiated perspective of diversity, toxin productivity and occurrence of Amphidomataceae in a poorly explored region of the global ocean.