Caution: Harmful algal blooms occur when certain phytoplankton species grow excessively and rapidly in coastal waters.
EATING contaminated shellfish can lead to poisoning within just 30 minutes, warns Prof Dr Lim Po Teen (pic, below).
According to the Universiti Malaya Institute of Ocean and Earth Sciences professor, early symptoms of paralytic shellfish poisoning (PSP) include numbness of the lips and tongue.
“In severe cases, victims may experience paralysis and respiratory failure,” he said.
He stressed that anyone showing signs of poisoning should seek immediate medical treatment.
Prof Lim’s warning comes following recent reports by the Negri Sembilan Fisheries Department of elevated biotoxin levels exceeding safety limits, prompting fishers in Port Dickson to cease harvesting shellfish, including mussels.
Urging consumers to avoid shellfish harvested from affected coastal waters, Prof Lim said the toxins responsible, known collectively as saxitoxins, are potent neurotoxins that block sodium channels.
“There are more than 50 types of saxitoxins, and just 2mg is enough to cause death in an adult,” he said in an Aug 11 press release.
Prof Lim, whose research team is based at the Bachok Marine Research Station in Kelantan, has been studying harmful algal blooms (HABs) for more than 25 years, investigating species responsible for both human poisoning and massive fish mortality.
Currently serving as vice-president of the International Society for the Study of Harmful Algae, his contributions to the field earned him election as a fellow of the Academy of Sciences Malaysia this year.
He said HABs occur when certain phytoplankton species grow excessively and rapidly in coastal waters.
“When these blooms occur near aquaculture sites, toxins from the microalgae can accumulate in filter-feeding shellfish such as oysters, cockles and mussels. Once toxin levels surpass safety limits, the shellfish are unsafe for consumption,” he explained.
Prof Lim noted that regular plankton and shellfish monitoring by the Department of Fisheries Malaysia is vital to detect blooms early, prevent contaminated shellfish from reaching markets, and protect public health.
“Once an algal bloom subsides, shellfish can naturally purge toxins, but this process may take several weeks to a few months.
”Globally, harmful algal bloom events are on the rise, driven by ocean warming, climate change and coastal eutrophication caused by nutrient discharges such as nitrogen and phosphorus,” the press release read.
