Diarrhetic Shellfish Toxin Monitoring in Commercial Wild Harvest Bivalve Shellfish in New South Wales, Australia

• Main Authors: Hazel Farrell, Penelope Ajani, Shauna Murray, Phil Baker, Grant Webster, Steve Brett, Anthony Zammit
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Toxins
• Subjects: diarrhetic shellfish toxins; <i>Dinophysis</i>; wild harvest; bivalve shellfish; pipis (<i>Plebidonax deltoides</i>); Sydney rock oyster (<i>Saccostrea glomerata</i>)
• Online Access: https://www.mdpi.com/2072-6651/10/11/446

An end-product market survey on biotoxins in commercial wild harvest shellfish (<i>Plebidonax deltoides</i>, <i>Katelysia</i> spp., <i>Anadara granosa</i>, <i>Notocallista kingii</i>) during three harvest seasons (2015&#8315;2017) from the coast of New South Wales, Australia found 99.38% of samples were within regulatory limits. Diarrhetic shellfish toxins (DSTs) were present in 34.27% of 321 samples but only in pipis (<i>P. deltoides</i>), with two samples above the regulatory limit. Comparison of these market survey data to samples (phytoplankton in water and biotoxins in shellfish tissue) collected during the same period at wild harvest beaches demonstrated that, while elevated concentrations of <i>Dinophysis</i> were detected, a lag in detecting bloom events on two occasions meant that wild harvest shellfish with DSTs above the regulatory limit entered the marketplace. Concurrently, data (phytoplankton and biotoxin) from Sydney rock oyster (<i>Saccostrea glomerata</i>) harvest areas in estuaries adjacent to wild harvest beaches impacted by DSTs frequently showed elevated <i>Dinophysis</i> concentrations, but DSTs were not detected in oyster samples. These results highlighted a need for distinct management strategies for different shellfish species, particularly during <i>Dinophysis</i> bloom events. DSTs above the regulatory limit in pipis sampled from the marketplace suggested there is merit in looking at options to strengthen the current wild harvest biotoxin management strategies.