Cases of Marine Fish Poisoning

Cases of Marine Fish Poisoning

By Rafael D. Guerrero III


Some marine fish become poisonous after feeding on toxin-producing organisms.


            With the frequent occurrence of red tide on Philippines waters, the public has become wary and discriminating in its choice of seafood. The red tide renders bivalves like mussels, oysters and clams in affected coastal areas unsafe for human consumption. Fishes are generally not problematic as long as people remove their gills and entails before they are cooked and eaten.

            There are instances, however, when marine fish poisonings do occur and lead to sickness or even death. Cases of ciguatera, pufferfish poisoning and goby fish poisoning have occurred in the country.

            Ciguatera is a disease caused by the eating of toxic fishes that inhabit like red snappers, groupers and eels become poisonous when they prey on plant-eating fishes like the surgeonfish (“labahita”). These have, in turn, eaten blue-green algae present in coral reefs producing the poisonous substance.

            The symptoms of ciguatera are prickling of lips, tongue and throat; numbness, nausea and vomiting. The victim may also experience dryness of mouth, abdominal cramps and insomnia. While the death rate for the disease is usually low, recovery is slow and may take several months.

            The poison causing ciguatera is known as ciguatoxin. Although there is no known antidote for the disease, the intravenous administration of mannitol reportedly alleviates symptoms. The disease is common in the South Pacific where the incidence is estimated to be as high as 500 cases per 100,000 inhabitants. The fatality rate is a low 0.1 percent.

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Oyster and Mussels in Western Visayas

Oyster and Mussels in Western Visayas

By Giselle PB. Samonte


Research should focus on increasing production and preventing red tides.


The slipper oyster (talaba) and the green mussel (tahong) are the only mollusk species being farmed in the Philippines.

The Western Visayas region in the central Philippines is one of the major sources of oysters and mussels, which are farmed for their meat. Production is mainly for the domestic market.

            The need of the people in the region to augment their income from fishing has led to the proliferation of oyster and mussel farms.

            The farms started operations as early as the 1950s. There are today an estimated 2,000 coastal families in the region which are engaged in the mollusk farming. Oysters are farmed along rivers using the bottom, stake, rack-hanging and raft-hanging methods.

            In the bottom method, oyster shells or large stones are scattered on the sea bottom for oyster spat fall.

            In the stake method, whole or halved bamboo poles are used as substrates for oysters.

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