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Nuclear Techniques to Study the Red Tide Problem

Project Number: PHI/7/006


To transfer the nuclear based receptor binding assay technology and to assist in sediment studies in order to manage the toxic red tide problem.


The Philippines has a 17,460 km coastline and 185,000 km2 of shelf area, hence vast areas for harvest fisheries and mariculture. Since 1983, nine major coastal areas have been affected by Pyrodinium bahamanse var. compressum, or toxic red tides. Manila Bay is one of the most heavily affected areas, Pyrodinium bloom having been recorded there almost annually since 1989. Losses to the Philippine seafood industry could be as high as $300,000 per day at the height of red tide season, and to date there have been 1,824 paralytic shellfish poisoning (PSP) cases and 109 deaths. While monitoring and research have been very useful in enhancing management schemes for harmful algal bloom (HAB) in other countries, there is a dearth of such activities in the Philippines. Monitoring HAB in the Philippines started only in the early 1990s while research efforts on the red tide problem have been fairly recent and rather marginal due to lack of expertise and equipment. The Agency started supporting red tide studies under this project in 1997 and will continue to do so in the next biennium. The project will be implemented at the Philippine Nuclear Research Institute (PNRI), and will help develop the rapid assay technique based on tritium labelled saxitoxin for PSP toxin determination. The technique will be extended to the Bureau of Fisheries and Aquatic Resources (BFAR), responsible for routine monitoring of red tide toxin, as a substitute for the live mouse bioassay. Meanwhile, studies on radiometric dating and cyst identification in sediment cores will be conducted for correlation with red tide occurrences. As a result, the monitoring and management scheme for HAB will be strengthened.

National Commitment:

All facilities, including a tritium labelling laboratory which will be available in 1999; equipment and consumables; personnel; research funds and operating costs.

Agency Input:

Expert services in tritium labelling for saxitoxin, receptor binding assay and sediment dating; equipment, including an HPLC, an alpha spectrometry system and a photomicroscope; training in receptor binding assay and radiometric dating.

Project Impact:

Establishment of a rapid assay method for determining PSP toxin in shellfish and identification of the factors promoting HAB occurrence will increase the efficiency of HAB monitoring and reduce the number of poisoning cases and deaths due to PSP. In the long run, the project will lead to the mitigation and elimination of HAB and contribute to the national economy