ANSWER 1

Climate change is likely to have impacts across the whole supply chain from production through to distibution.
During production:

• warmer sea temperatures will increase the growth and extend the distribution of several human pathogenic bacteria, such as Vibrio. In Australia, Vibrio parahaemolyticus is particularly relevant, having caused several outbreaks recently associated with oysters.
• changing environmental conditions will change the distribution of Harmful Algae, and the presence of marine biotoxins. There are many different types of harmful algae in Australia, we can expect some to increase their abundance whereas others will decrease, and distributions may change geographically.
• Increased rainfall and flood events can result in increased enteric pathogens washing in from terrestrial environments, especially if sewage systems fail. Examples include Norovirus, Salmonella, hepatitus A. Strict protocols are in place in commercial shellfish growing areas to manage this, but recreational consumers need to be aware as well.
• Poor fish health associated with environmental extremes or increase loads of fish pathogens may result in increased use of therapeutants in aquaculture. Strict withholding periods are in place to stop recently treated fish from entering the supply chain.
• Pesticides and herbicide use in terrestrial agriculture is expected to increase with climate change impacts and weeds and pest distributions change. These can run-off into aquatic waterways, exposing seafood species.
• increased temperatures increase spoilage rate and histamine production in susceptible fish. Time to refrigeration is an important concern and efforts are increased in summer months to ensure seafood enters the cool chain asap to maintain both quality and safety. Maintaining cool chain throughout supply is also critical.

Supply chain risks:

• extreme heat increases the likelihood of cold-chain failures during transport and storage, particularly relevant for Australia’s long seafood supply chains
• floods, storms and bushfires disrupt transport and freight networks, placing pressure on the maintenance of the cool chain

References:
Harlock et al. 2018. Emergence of non-choleragenic Vibrio infections in Australia.https://pubmed.ncbi.nlm.nih.gov/35168502/
Fearnely et al. 2024. Vibrio parahaemolyticus Foodborne Illness Associated with Oysters, Australia, 2021-2022. https://pubmed.ncbi.nlm.nih.gov/39447146/
Hallegraeff et al. 2021. Overview of Australian and New Zealand harmful algal species occurrences and their societal impacts in the period 1985 to 2018, including a compilation of historic records. https://pubmed.ncbi.nlm.nih.gov/33875178/
Brett et al. 2020. Harmful Algal Blooms and the shellfish industry. https://www.imosoceanreport.org.au/wp-content/uploads/2020/02/STAR3.4-.Brett.et.al.pdf
Fleming et al. 2014. Climate change risks and adaptation options across Australian seafood supply chains – A preliminary assessment. https://www.sciencedirect.com/science/article/pii/S2212096313000065