Dept: Red tide detected in Sabah waters
Kota Kinabalu: The State Fisheries Department issued a red tide warning, Wednesday, advising the public to refrain immediately from consuming any type of shellfish or bivalves obtained from the sea.
This includes oysters (tiram), mussels (kupang), cockles (kerang) and any type of clam-like seafood.
Its Director, Rayner Stuel Galid (pic), said a year-long Red Tide Monitoring Programme conducted by the department, in collaboration with the State Health Department, has detected the presence of Paralytic Shell Fish Poisoning (PSP) toxins in samples of bivalves (kerang) from waters of certain parts of the State's west coast.
He said the samples taken from Kuala Penyu (particularly Sitompok Lake area) and from waters off Kota Kinabalu, including Gaya Island, Sepanggar Bay (including Kuala Menggatal) and Likas Bay, as well as Papar, Putatan and Tuaran districts have shown to contain toxic levels of PSP toxins.
Additionally, the department also detected the presence of high densities of the PSP-causative organism, that is the dinoflagellate, Pyrodinium bahamense var compressum, in samples of sea water from these areas.
The numbers become so large and dense that sometimes they impart a brownish-red colour to the sea. These findings are consistent with the results of analysis of toxic shellfish mentioned earlier, he added.
According to Rayner, the mouse bioassay, the method for analysis of PSP in shellfish by the department at its research centre in Likas, found some of the shellfish samples to have as high as 4,010 Mouse Units (MUs) (Papar) and 1,270MU (Tuaran), which are considered as very toxic.
Red tide occurrences in Sabah in the past years have revealed bivalves to be as toxic as 8,000MU. The lowest limit as the dangerous level for humans is 400MU.
"If consumers do wish to eat bivalve shellfish, they are advised to make sure these are not obtained from waters off the West Coast of Sabah," Rayner said.
While it is impossible to test every shellfish and fish from the sea for toxins, he said the department declared that this red tide is occurring in the areas mentioned above and there is a high possibility that other adjoining districts will be affected in future.
It is also expected that shellfish will become more toxic as these dinoflagellates become more numerous in the sea.
Paralytic shellfish poisoning is a marine biotoxin that is associated with certain types of algae blooms in coastal waters. Paralytic shellfish poisons are accumulated in shellfish which have filter-fed upon toxic one-celled microscopic algae called dinoflagellates, which occurs naturally as a part of the ocean plankton.
Eating toxic shellfish can cause paralytic shellfish poisoning (PSP) in humans. PSP is caused by saxitoxin, which is produced by the dinoflagellate, Pyrodinium bahamanse (var. compressum) and is one of the most potent toxins known to scientists.
The first recorded PSP case in Sabah was in 1976 where 202 victims suffered and saw seven deaths. Since then PSP occurrences have been detected every few years off the West Coast.
Early symptoms of PSP include tingling of the lips and tongue, which may begin within minutes of eating poisonous shellfish or may take an hour or two to develop.
Depending on the amount of toxin a person has ingested, symptoms may progress to a sensation of "pricking of pins and needles" of the skin and then loss of control of arms and legs, followed by difficulty in breathing.
Some people have experienced a sense of floating or nausea, he said, adding if a person consumes enough poison, muscles of the chest and abdomen become paralysed.
He said death can result in as little as two hours, as muscles used for breathing become paralysed.
"If one experiences the above symptoms, get medical treatment immediately at the nearest hospital or clinic. There is no medication available for PSP or Saxitoxin poisoning; in general, supportive measures are the basis of treatment for PSP and in severe cases, with the use of a mechanical respirator and oxygen," Rayner said.
He said the types of sea life considered safe to eat include all types of prawns and crabs including shovel-nosed lobsters, mantis shrimps, all types of coral fishes and fishes which are predatory such as sharks and stingrays, barracuda, tenggeri, jacks, etc, and deepsea fishes.
However, as a prudent measure consumer they are advised to throw away the guts and gills of any fish to be eaten and these same fishes are to be washed properly.
Also, any type of dried, canned, bottled or salted fish products are safe.
The department is currently doing further sampling and testing on fishes and sea life collected from other districts to determine whether these are also toxic and dangerous to human health.
For further information visit website http://www.fishdept.sabah.gov.my/download/redtideinfo.doc