Safer Seafood: IAEA Develops Tools to Help Fight Toxic Marine Algae

When tiny marine organisms grow uncontrolled, forming what is called a harmful algal bloom, their toxins can make people sick, harm ocean life and cause millions of dollars in lost seafood revenues. To help mitigate the outbreaks of these toxins, scientists at the IAEA are working with researchers in Cuba to detect and measure biotoxins in the ocean and to develop monitoring and reference tools that will help control such outbreaks worldwide.

With a better understanding of how harmful algal blooms behave and how their toxins enter the food chain, it will be easier for countries to monitor toxins and control the consumption of contaminated seafood, said Marie-Yasmine Dechraoui-Bottein, a research scientist at the IAEA leading this collaborative project with the Centre de Estudios Ambiantales de Cienfuegos (CEAC) in Cuba. Harmful algal blooms have a particularly big impact on small island states that rely heavily on their fisheries and tourism.

In Cuba, the fishing and sale of thirteen fish species including groupers, snappers and jacks have been prohibited year-round since 1996 due to a high risk of ciguatera fish poisoning � due to toxic algae. It is only recently that Cuban scientists, with the help of the IAEA, acquired the capability to measure ciguatera toxins in seawater and in fish and shellfish using a nuclear technique called the receptor binding assay (RBA), a specific and sensitive monitoring tool that is based on measuring the interaction between the toxins and receptors marked with radioactive labels.

During the course of a recent field mission in Cuba, a team of IAEA scientists and local fishermen collected fish and algae samples at different depths to study the distribution of toxic harmful algal bloom species.

Once the samples have been processed in Cuba, they will be tested at the IAEA’s marine laboratory in Monaco. As a result, the IAEA will develop the first-ever reference material for ciguatoxin monitoring worldwide. Such reference materials are critical for national authorities in managing marine environments and adhering to fish trade regulations.

While the exact number of people affected and economic losses are difficult to estimate, the impacts of harmful algal blooms are nevertheless considerable. With these data and reference materials, we can refine how we monitor toxins to help minimize their impact, said Dechraoui-Bottein. It is important to keep in mind that ciguatera fish poisoning remains the most common non-bacterial seafood intoxication worldwide.

The damage caused by harmful algae blooms

Harmful algal blooms are conglomerations of ocean-borne microorganisms that can be red, blue, pink or even invisible to the naked eye. They can produce natural toxins such as neurotoxins, which may accumulate in marine fish and shellfish to quantities that are dangerous for human consumption. Eating seafood contaminated with these biotoxins can cause a range of symptoms, from gastrointestinal problems to severe neurological effects and, in rare cases, even death.

Harmful algae bloom outbreaks affect many regions around the world, from the Americas to North Africa to Asia. In the last few years, outbreaks of harmful algal blooms have plagued areas of coastline and inland lakes of the Americas.

For example, in February 2016, harmful algal blooms in Chile decimated 40 000 metric tons of salmon, causing a loss of around $500 million for the local fishing industry as well as a hike in the price of salmon. In 2014, a large bloom in Lake Erie disrupted the water supply of 500 000 Ohio residents for three days.

Source: International Atomic Energy Agency