Comparative paralytic shellfish toxin accumulation in three important Aotearoa New Zealand marine invertebrate species: kina (<i>Evechinus chloroticus</i>), pāua (<i>Haliotis iris</i>) and hohehohe (<i>Panopea zelandica</i>)

This study investigated the potential for paralytic shellfish toxin (PST) accumulation in three of Aotearoa New Zealand's (NZ) taonga seafood species: kina (urchin; <i>Evechinus chloroticus</i>), pāua (abalone; <i>Haliotis iris</i>) and hohehohe (geoduck; <i>Panopea zelandica</i>) in laboratory exposures to the dinoflagellate <i>Alexandrium pacificum</i>. Although PST accumulation data are scarce or non-existent for these three species, international studies have reported toxin accumulation in related genera. Given the prevalence of harmful algal blooms (HABs) in areas of NZ where these species are harvested, this research aimed to assess PST uptake in different tissue types (e.g. viscera, siphons, flesh) following a seven-day controlled exposure to the PST-producing <i>A. pacificum</i>. Results showed that while the filter feeding hohehohe exceeded regulatory PST limits in the viscera following exposure, the two grazing species (kina and pāua) did not accumulate PSTs beyond the regulatory limit of 0.8 mg STX.2HCl eq kg⁻¹ in 7 days. However, <i>A. pacificum</i> DNA and PSTs were detected in the viscera of all species, confirming ingestion of the microalgal cells. This is the first controlled PST-uptake study of these economically and ecologically important species, providing valuable insights into the risks of paralytic shellfish poisoning following collection of these species after a HAB event.