Harmful Algal Bloom Impact Assessment – Impacts on Oysters
Provided scientific assessment of Karenia spp. blooms on South Australian oysters, identifying toxicity mechanisms, monitoring strategies, and practical management actions to support aquaculture resilience and industry recovery.
Location: South Australia
Client/Sector: Oyster aquaculture industry
Challenge:
During a regional harmful algal bloom event involving Karenia spp., uncertainties around actual impacts of the bloom on oyster health required scientific investigation. There was uncertainty regarding the mechanisms of toxicity, whether oysters responded differently from other filter-feeding marine organisms, and what management actions could help mitigate impacts and support industry recovery.
Aquatic Assessments Role:
Aquatic Assessments worked with academic partners to review the scientific literature on Karenia spp. toxicity and analyse field observations of oysters responses during the bloom. The work examined physiological responses such as mantle retraction and loss of responsiveness, evaluated possible mechanisms of toxicity including reactive oxygen species and gill irritation, and identified key uncertainties relevant to oyster aquaculture. Aquatic Assessments also developed a framework of recommended actions for monitoring, bloom management, and long-term industry resilience.
Outcome:
The assessment provides oyster growers and industry stakeholders with evidence-based guidance on the likely mechanisms of bloom impacts, practical management responses during bloom events, and priorities for future monitoring and research to improve resilience of South Australia’s oyster aquaculture sector.