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Harmful Algal Blooms (HABs)

Collection of Harmful Algae in Juag Lagoon (Philippines); to quantify Pyrodinium Bahamense cell density and Paralytic Shellfish Poisoning toxins levels

One of the most serious and visible problems facing coastal waters is related to the phenomena commonly known as red tides and called harmful algal blooms (HABs). Certain algal species produce toxins that can accumulate in seafood products thus posing a risk to human consumers. The occurrence of HABs that impacts both humans and environmental health increased in both frequency and worldwide distribution during the latter third of the last century. Virtually, every coastal country worldwide is now affected, often by multiple toxic or harmful species.

Field uptake studies in Juag Lagoon (Philippines); a site experiencing Harmful Algal Blooms. A natural laboratory wherein uncontaminated mussels are immersed and uptake/depuration of harmful algal toxins is observed.

There are still important gaps in our knowledge of the ways in which seafoods become contaminated by HABS toxins. MEL and its Collaborating Centre (Philippines Nuclear Research Institute) are addressing some of these requirements for knowledge through a key application of nuclear technologies, i.e. the receptor binding assay or RBA, a rapid, sensitive and high throughput technique, which ensures sustained and effective shellfish toxicity monitoring. This method is currently applied to field uptake studies in Philippines aquaculture areas, to measure the transfer and the elimination of the biotoxin causing Paralytic Shellfish Poisoning during HABs events, from toxic algal cells into green mussels. Future work will focus on the preparation of a radiolabeled toxin to be used to measure the absorption of biotoxins by molluscan shellfish directly from the aquatic medium, their subsequent tissue distributions, and the transport up the food chain to fish and crustacean predators that can also be consumed by humans.

To further link this scientific information to decision-making in fisheries management, a Coordinated Research Programme was initiated by MEL in 2007 in collaboration with the IAEA/FAO. Its general objective is to integrate studies on applications of nuclear techniques to HABS bioaccumulation in molluscs and food chain transfer with risk management decision-making, in relation to suitability for human consumption. One of its envisaged outcomes will be a better valuation of the economic contribution that these nuclear technologies make to enhancing seafood safety and consequently national and international trade in these valuable commodities.

Regional (ARCAL) First Planning and Coordination Meeting in La Havana (Cuba) to launch the new project on HABs for 2009-2011

MEL-REL also supports the Technical Cooperation programme of the Agency, addressing the impacts of Harmful Algal Blooms on human health and seafood safety. In this framework, a World Summit on Sustainable Development Partnership (Type II Initiative) with IOC-UNESCO was approved in 2002 to establish the capability of African Member States to monitor toxic algae and to quantify toxins levels in seafood. http://www.ioc-unesco.org/hab

Regional (AFRA) Training Course in Cape Town (South Africa) on the Receptor-Binding Assay method to quantify Harmful Algal toxins in phytoplankton and shellfish.

In addition, MEL-REL recently initiated and developed an international network of laboratories for the combined production of radiolabelled saxitoxin used in the Receptor Binding Assay technique.

Links to:

TC projects on HABs : IAEA & Harmful Algal Blooms