Improving risk management of paralytic shellfish toxins in Blacklip Abalone ( Haliotis rubra rubra )

The accumulation of paralytic shellfish toxins (PST) of microalgal origin in abalone tissues causes a trade and human health risk that requires active management. Toxic algal blooms of the genus Alexandrium have recently caused several abalone harvest closures on the east coast of Australia. Risk management is hampered by a scarcity of knowledge on the mechanisms and rates of accumulation and depuration of the associated PST. A collaborative effort by researchers from the South Australian Research and Development Institute (SARDI), the Institute of Marine and Antarctic Science (IMAS) and Cawthron Institute conducted field studies on the east coast of Tasmania during toxic blooms in 2018 and 2019, and experimental studies in South Australia in 2018 to investigate uptake and depuration of PST from A. catenella in Haliotis rubra rubra, Blacklip Abalone. Several key results from the study will be used to inform improved risk management of this issue. In particular, we showed for the first time that: abalone can accumulate PST from exposure to toxic algal cells; the predominant accumulation is in the foot tissue; and toxins depurate extremely slowly from this tissue. We conducted a successful laboratory validation of a rapid screening test for PST analysis in foot tissue for future use during A. catenella blooms that should lead to significant savings in PST monitoring in Tasmania.