Algal blooms of <em>Alexandrium</em> spp. and Paralytic Shellfish Poisoning toxicity events in mussels farmed in Sicily

Abstract

Marine biotoxins can accumulate in filter-feeders bivalve molluscs, that may represent a source of potential health problems being vectors of toxins, that are transferred to humans through their consumption. Harmful Algal Blooms impact on aquaculture may give also economic losses due to temporary closures of contaminated shellfish harvest and marketing. The presence of toxic algae for Paralytic Shellfish Poisoning (PSP), with recurrent toxic blooms of dinoflagellates, such as several Alexandrium species, been known since 2000 in the waters of an Ionian bay of Sicily, the Syracuse harbour, where shellfish farms are located. Our previous works reported in this area the positivity for PSP toxin in mussels (Mytilus galloprovincialis) with saxitoxin concentrations above the limit of the law and the simultaneous presence of toxic species of the genus Alexandrium in the waters. This work reports new recent episodes of algal blooms of Alexandrium minutum in the waters of the Syracuse harbour and PSP toxin contamination in farmed mussels, with values beyond the limits established by law, with the consequent immediate closure of the production area. PSP toxicity was detected with the MBA (Mouse Bioassay) with the confirm carried out with Lawrence method to quantify the total saxitoxin equivalents and characterize the toxic profile. Regular application of the implemented health plan is very important in order to prevent any risk and protect consumer health.

Microbiological and Toxicological Investigations on Bivalve Molluscs Farmed in Sicily

“…But more recently, other toxic species such as A. pacificum Litaker, 2014 (former A. catenella (Whedon & Kof.) Balech, 1985), were identified apart from A. minutum Halim and PSP-positive samples, which were detected between late winter and early spring [41,73,75]. Contamination by the PSP toxin in farmed mussels, with values beyond the limits established by law, leads to the consequent immediate closure of the production area.…”

“…High concentrations of saxitoxins generally induce death within 5-10 min [40]. An aliquot of positive samples was sent to the National Reference Laboratory (NRL) in Cesenatico for confirmation and quantitation as described before [41] Microscopy Analysis for the Detection of Biotoxin-Producing Algae in Water…”

“…In particular, 7/10 positive samples induced the death of mice early after jugular injection (<10 min), and their saxitoxins content, detected using LC MS/MS, was over the legal limit (800 µg STXeq/kg): PST analysis conducted by the NRL of Cesenatico detected a maximum toxicity of 8.139 µg STXeq/kg e.p. [41]. Seawater samples, collected together with the PST-containing mussels, were subjected to microscopy analyses, revealing the saxitoxin-producing algae Alexandrium minutum Halim with values between 60 and 5400 cell/L [41].…”

“…[41]. Seawater samples, collected together with the PST-containing mussels, were subjected to microscopy analyses, revealing the saxitoxin-producing algae Alexandrium minutum Halim with values between 60 and 5400 cell/L [41].…”

Alien Species Associated with New Introductions and Translocations of Commercial Bivalves in Italian Marine Waters

“…In fact, the intervalvular water of live animals and the water used to collect and transport the seeds may constitute a suitable environment for potentially toxic phytoplankton. This issue should be carefully assessed since the frequency and impact of harmful algal blooms and the toxin occurrence is a concrete and relevant problem for Italian shellfish production [123][124][125].…”