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Unprecedented Alexandrium blooms in a previously low biotoxin risk area of Tasmania, Australia
conference contribution
posted on 2023-05-23, 12:54 authored by Gustaaf HallegraeffGustaaf Hallegraeff, Christopher BolchChristopher Bolch, Condie, S, Dorantes Aranda, JJ, Murray, S, Quinlan, R, Ruvindy, R, Alison TurnbullAlison Turnbull, Sarah UgaldeSarah Ugalde, Wilson, KDuring October 2012, a shipment of blue mussels (Mytilus galloprovincialis) from the poorly monitored east coast of Tasmania, Australia, was tested by Japanese import authorities and found to be contaminated with unacceptable levels of Paralytic Shellfish Toxins (PSTs; 10 mg/kg). Subsequently local oysters, scallops, clams, the viscera of abalone and rock lobsters were also found to be contaminated. This led to a global product recall and loss to the local economy of AUD 23M. Following low toxicity during 2013 and 2014 and implementation of minimal shellfish farm closures, a more severe bloom event occurred during July-November 2015 and again June-September 2016 (up to 300,000 Alexandrium cells/L; 24 mg/kg PST in mussels, 6 mg/kg in Crassostrea gigas oysters), also causing 4 human illnesses resulting in hospitalization after consumption of wild shellfish. While Alexandrium tamarense had been detected in low concentrations in southeastern Australia since 1987, all cultured strains belonged to the mostly non-toxic group 5 (now designated A. australiense; detected since 1987) and weakly toxic group 4 (A. pacificum; detected in 1997). In contrast, the 2012 to 2016 outbreaks were dominated by highly toxic group 1 (A. fundyense) never detected previously in the Australian region. Molecular analyses suggest that A. fundyense may have been a cryptic ribotype previously present in Tasmania, but newly stimulated by altered water column stratification conditions driven by changing rainfall and temperature patterns. Increased seafood and plankton monitoring of the area now include the implementation of Alexandrium qPCR, routine Neogen™ immunological and HPLC PST tests, but ultimately may also drive change in harvesting strategies and aquaculture species selection by the local seafood industry.
Funding
Fisheries Research & Development Corporation
History
Publication title
Proceedings of the 17th International Conference on Harmful Algae 2016Editors
LAO Proenca, GM HallegraeffPagination
38-41ISBN
9788799082766Department/School
Institute for Marine and Antarctic StudiesPublisher
International Society for the Study of Harmful Algae (ISSHA), Intergovernmental Oceanographic Commission of UNESCOPlace of publication
Copenhagen, DenmarkEvent title
17th International Conference on Harmful Algae 2016Event Venue
Florianopolis, BrazilDate of Event (Start Date)
2016-10-09Date of Event (End Date)
2016-10-14Rights statement
Copyright unknownRepository Status
- Restricted