Protecting marine aquaculture and human health from the negative effects of algal blooms
A team from the Scottish Association for Marine Science (SAMS), a partner of UHI, undertook research which minimised the serious risks posed by harmful algal blooms (HABs) to the economic sustainability of the aquaculture industry and the health of consumers.
Unit of assessment | Earth Systems and Environmental Science
Scotland’s aquaculture industry, including both finfish and shellfish production, contributes around £620 million a year to the Scottish economy, supports over 12,000 jobs, and generates employment in remote rural areas.
But this industry faces environmental challenges, not least from naturally occurring harmful algal blooms (HABs) which can form quickly and become toxic. These toxins are taken up by commercially harvested shellfish, including mussels, scallops, and oysters. As well as posing a potentially fatal threat to human health, this contamination has severe economic effects, including the closure of shellfish farms. Other HAB species can kill farmed fish, which also has significant economic impact.
UHI research on predicting where and when such HABs will occur has minimised the serious risks to the economic sustainability of the aquaculture industry and the health of consumers.
Specifically, understanding the development of HABs allows rapid reporting and forecasting of toxin-producing HABs. This allows shellfish producers and the regulatory body Food Standards Scotland (FSS) to suspend harvesting or undertake tests to verify the safety of the product. Since 2014, this work and expertise has underpinned the safe supply of almost 15 million Scottish shellfish portions to UK and international consumers without a single reported poisoning case. The work has also informed HAB regulatory monitoring guidance produced for all European Union (EU) member states.
In addition, forecasting HABs that are harmful to fish directly benefits the finfish aquaculture industry and enables the Scottish Environment Protection Agency (SEPA) and Marine Scotland (MS) to maximise fish welfare.
UHI research, led by Professor Keith Davidson at SAMS, has examined the ecology of HAB events and the conditions that contribute to the development and movement of the most important harmful algae in UK and other temperate waters: shellfish biotoxin producing Alexandrium, Pseudo-nitzschia, Dinophysis, and ichthyotoxic Karenia.
Researchers used this knowledge to build computer models of bloom development. The work has explained the factors that govern blooms of the harmful species Karenia mikimotoi, which can cause significant farmed fish mortalities, and has evaluated how climate change and pollution has influenced the frequency and intensity of HABs in UK waters.
Confidence in the aquaculture industry was damaged in 2013 when 70 people were poisoned by biotoxins generated by HABs in mussels harvested in Shetland and served in London restaurants. In response, SAMS was funded by Seafood Shetland to produce weekly risk assessment bulletins for the Shetland Islands, an area that now accounts for around 80% of national shellfish production.
SAMS also operates the harmful phytoplankton monitoring component of the FSS regulatory shellfish safety monitoring programme. The team analyses water samples collected on a weekly basis from 40 monitoring sites around Scotland. Since 2014, the team has analysed (by August 2020) 9,788 samples and found 4,641 instances of dangerously high algal cell densities.
SAMS research directly influences the way regulators and policy makers communicate with the public about HAB and biotoxin risks and informs pan-European guidance on which harmful phytoplankton and biotoxins should be monitored and how this monitoring should be undertaken in the EU.
“SAMS research directly influences the way regulators and policy makers communicate with the public about HAB and biotoxin risks”