Lobster Supply Chains Are Not at Risk from Paralytic Shellfish Toxin Accumulation during Wet Storage

Abstract

Lobster species can accumulate paralytic shellfish toxins (PST) in their hepatopancreas following the consumption of toxic prey. The Southern Rock Lobster (SRL), Jasus edwardsii, industry in Tasmania, Australia, and New Zealand, collectively valued at AUD 365 M, actively manages PST risk based on toxin monitoring of lobsters in coastal waters. The SRL supply chain predominantly provides live lobsters, which includes wet holding in fishing vessels, sea-cages, or processing facilities for periods of up to several months. Survival, quality, and safety of this largely exported high-value product is a major consideration for the industry. In a controlled experiment, SRL were exposed to highly toxic cultures of Alexandrium catenella at field relevant concentrations (2 × 105 cells L−1) in an experimental aquaculture facility over a period of 21 days. While significant PST accumulation in the lobster hepatopancreas has been reported in parallel experiments feeding lobsters with toxic mussels, no PST toxin accumulated in this experiment from exposure to toxic algal cells, and no negative impact on lobster health was observed as assessed via a wide range of behavioural, immunological, and physiological measures. We conclude that there is no risk of PST accumulation, nor risk to survival or quality at the point of consumption through exposure to toxic algal cells.

Field Validation of the Southern Rock Lobster Paralytic Shellfish Toxin Monitoring Program in Tasmania, Australia

“…However, no field studies have been published. For the Tasmanian rock lobster fishery, the combination of previously published experimental work [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 34 ] and the field studies reported herein have provided a strong evidence base for continued progressive improvements to the Tasmanian risk management program.…”

“…Environmental conditions likely to trigger A. catenella blooms were determined to be water temperatures of 10–15 °C and stratification of coastal waters via salinity and/or temperature gradients [ 1 ]. Experimental studies feeding highly toxic mussels to J. edwardsii found: exponential uptake and depuration rates of 6 and 7% per day, respectively; potential excretion routes for PST are via the faeces, antennal glands and gill; there is no impact of PST on lobster health; and confirmed PST uptake did not occur through direct exposure to A. catenella cells, as would occur in boat wells, sea cages and holding facilities of the live lobster supply chain [ 8 , 9 , 10 ].…”