![]() The movement of theĪlgal blooms along the South China coast was attributed to the 1997-98Įl Nino event. Kong in Nov 1997, to Hong Kong in Apr 1998. Of harmful algal blooms from the South China coast east of Hong Resulted in the loss of 32 million US dollars in fish kill damage. In Hong Kong, the red tides which occurred between mid-March and mid-April 1998 Sandakan, Tawau, Kunak and Lahad Datu (Star Online, ). Including from Kota Kinabalu, Kuala Penyu, Beaufort, Papar, Kudat, The prevalence of toxin in samples tested from many parts of Sabah To adhere to the Fisheries Department's advice not to fish or consume The Health Ministry issued a health alert asking the people in Sabah This promptedīrunei to immediately ban the import of fish, such as mackerel and Kota Kinabalu, were contaminated by the red-tide toxin. Warnings that the waters of Sabah, especially in Kuala Penyu and In December 1999, Sabah Fisheries Department issued Pyrolytic shellfish poisoning occurs from time to time in the state of Health cautioned the public against eating shellfish (Philippine < 500 cells per liter of sea water, toxin level < 40 micrograms However, remained within the tolerable level (i.e. The toxic algal densityĪnd red tide toxin present in shellfish gathered from these areas, ![]() ![]() Of Manila Bay in Bataan, Cavite and Navotas. In May 2000, Pyrodinium bahamense was again detected in parts There was no report of harmful algal bloom inġ999. In 1998,Īt least 2 casualties due to consumption of contaminated shellfish The toxic cases have been attributed to Pyrodinium blooms. Manila Bay, Philippines, especially near the Bataan and Cavite regions. Red tide is almost an annual event (usually from May to August) in the No significant bloom has been reported before. They have also spread to new locations (e.g. It is suspected that blooms are occurring more frequently in recent Shellfish poisonings have also been reported in Sabah, Malaysia. Occurred in the Manila Bay of Philippines, and near Brunei. The common bloom species are known to be harmful or even toxic.įor example, blooms of Pyrodinium bahamense var. (Courtesy of Mr Edwin Ginn, Hong Kong Observatory, the Government of the Hong Kong Special Administrative Region)Ī minor bloom of Trichodesmium observed in Singapore Water, off Bedok Coast, on 31 July 1997Īlgal blooms occur regularly in many parts of Southeast Asia. The reddish linear patches are locations of red tides. The toxins from HAB can accumulate in the food chain and eventually be consumed by humans to cause paralytic or diarrhetic shellfish poisoning.Ī photograph showing dead fishes in a fish farm killed during a red tide event at Lamma Island, Hong Kong (Source: The Straits Times, April 13, 1998).Īn aerial photograph showing the red tide situation in the Repulse Bay of Hong Kong on 10th November 1998.HABs can cause severe damage to the fishing and aquaculture industry due to fish kills.In situations whereby a bloom is dominated by toxic algal species, fish and shellfish can be poisoned by the toxins.When bloom collapses, the microbial respiration on the dead and decaying cells can lead to reduced oxygen concentrations that can kill fish and other aquatic organisms due to lack of oxygen.The dense layer of algae near to the water surface blocks sunlight from reaching the other aquatic life. ![]() In cases where an algal bloom is detrimental to human and other marine life, it is referred to as a harmful algal bloom (HAB).Īlgal blooms may cause harm by the following mechanisms: These blooms are commonly observed in coastal waters During an algal bloom event, there is a high cellĬoncentration of phytoplankton, usually dominated by a particularĪlgal species. Hence, they are commonly knownĪs Red Tides. Under certain favourable conditions, algae in the sea multiply to highĬoncentrations forming what is known as an algal bloom. Of phytoplankton concentration are often considered as a viable Phytoplankton concentration is correlated to Sunlight to convert carbon dioxide into food molecules by the process They constitute the base of the marine food web, using Phytoplanktons or algae are microscopic, single-celled plants that live Centre for Remote Imaging, Sensing and Processing, CRISPĬentre for Remote Imaging, Sensing and Prcessing (CRISP) ![]()
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