Wednesday, 26 July 2017
Red tide hits Omani waters yet again
Red tide hits Omani waters yet again

Joseph Benny

08/01/2011 3:26 pm

Omani waters have been hit yet again by red tide, but unlike previous years, it is not toxic this time round. Red tide is a common name for a phenomenon known as algal bloom in which large quantities of algae accumulate rapidly in sea water and results in discolouration of the surface water.
Some red tides are associated with the production of natural toxins, depletion of dissolved oxygen or other harmful effects. The algae release ammonia and nitrates to the water which when it enters the gills of the fishes, resulting in their death due to suffocation. Besides, they also reduce the amount of oxygen in water.
The red tide that hit Oman’s seas this time was first noticed by the Marine Ecology and Oceanography Section of the Marine Science and Fisheries Centre, Ministry of Fisheries, on December 17 in the waters between Musandam and Duqm. The presence of noctiluca scintillans, a species of alga that caused the red tide, was detected with the help of satellite images.

“We have constituted a high-level committee comprising the Ministry of Environment, Ministry of Regional Municipalities and Water, Ministry of Health, SQU, Royal Navy and the Muscat Municipality to study the phenomenon. Though it is not dangerous to the marine ecology, we have issued warnings and started awareness campaigns among the fishermen to minimise its impact,” said Dr Lubna Hamoud al Kharusi, director of Marine Science and Fisheries Centre.

“We have been constantly watching its movements. Currently, it is heading offshore and we can say that it is more than 20 nautical miles away from the shore,” she told Muscat Daily. “However, I cannot say it for sure that it will not again turn back. It all depends on the direction of currents. As part of the precautionary measures, we assess the daily updates on its movements. We also have collected water samples from many places to check the salt and oxygen levels and toxicity.”

Red tide has become a regular visitor to the seas in Oman. The current phenomenon has turned the water in the affected area green. In 2008 and 2009, the red tide caused by cochlodinium polykrikoides wreaked havoc on the Oman seas, killing more than 300 tonnes of marines species. It was visible at Musandam, Batinah, Muscat, Al Wusta and Dhofar.

According to the fisheries department officials, the most devastating red tide occurred in 1976 in Salalah, killing 1,000 tonnes of fishes. Other algae species which cause red tide in Omani waters are ceratium fucus, ceratium macroceros and prorocentrum micans, which hit the Masirah island in 2005, and coscinodiscus, which appeared in 2000 in the coastal areas of Barka, leaving 30 tonnes of fishes dead.

The Ministry of Fisheries has asked people not to take bath in places where red tide is noticed. People have been advised not to eat dead fish, shell fish or snails from the affected areas.

Besides setting up a helpline number (80070009), the Ministry of Fisheries is planning a workshop to chalk out a national plan to tide over the recurring phenomenon, Dr Lubna said.

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