Abu Dhabi, UAETuesday 22 October 2019

Red tide alert: Signs of climate change detected in UAE waters

Red tide discovered by fishermen in Ras Al Khaimah

An aerial image of an algal bloom patch taken from an aquaplane on the Dubai coast several years ago.
An aerial image of an algal bloom patch taken from an aquaplane on the Dubai coast several years ago.

A key indicator of climate change has re-emerged on the coast of Ras Al Khaimah.

An algal bloom patch, also known as red tide, was discovered just off the emirate on Monday.

Fishermen at the nearby Al Jazira Al Hamra port detected the bloom before reporting it to the authorities.

The RAK Fishermen’s Association said the patch only stayed for one day and did not cause any harm to marine life.

“I noticed the red tide patch at 9.30am on Monday while on a fishing trip,” said Humaid Al Zaabi, deputy manager of the association and one of the fishermen who saw the red tide.

“It was a small patch measure approximately four nautical miles in length and same in width.

“I didn’t see any dead fish near or around the patch, but our fishing cages that were left in the area were empty which means that no fish were swimming in the area.”

Red tide appears when a species of algae called dinoflagellates grows out of control.

The species contain pigments that vary in colour from brown to red during the day and can appear luminescent at night.

There are thousands of species of dinoflagellates and a few dozen can be extremely toxic to people and marine life.

Algal blooms are not harmful in small concentrations and were primarily caused by rising seawater temperatures.

“We see the red tide when the season changes from summer to winter that’s when the temperature change, and it doesn't stay for too long due to the current movement.,” said Mr Al Zaabi.

“I went to the same area yesterday, and it was gone.”

In 2008 and 2009, a red tide caused serious damage to the UAE’s marine life, damaging fish stocks, coral, and wiping out large populations of fish in Dibba Rock.

Khalifa Al Muhairi, manager of the association, said the red tide appears twice a year when the seasons change.

“It is a normal and harmless phenomenon that appears at the end of summer and winter each year when the temperature change,” said Mr Al Muhairi.

“There was no adverse effect detected on marine life and the fishing process.”

Last year, Saadiyat Beach in Abu Dhabi was closed to swimmers after a harmful algal bloom was found in the sea surrounding the island.

Hamdah Al Aslai, acting head of marine life section at the Ministry of Climate Change and Environment said the latest re-emergence of red tide was detected within a relatively small range.

“Red tide is a natural phenomenon that occurs when the environmental conditions, such as temperature, nutrient levels, and winds are optimal, causing a sharp spike in the population of phytoplankton and leading to what's called an algal bloom,” said Ms Al Aslai.

“It often occurs at the beginning of each season due to noticeable changes in water temperature. Lasting a few days at a time, the red tide leads to modifications in seawater characteristics and marine currents.”

Ms Al Aslai offered assurances the red tide detected in RAK was not toxic.

However, she warned red tide can be an indication of climate change on marine environments.

“Even though red tides are seasonal natural phenomena, they can be aggravated by climate change," said Ms Al Aslai.

“Some of the most prominent impacts of climate change on the marine environment include rising temperatures, acidification, and deoxygenation, all of which are major factors in the occurrence of red tides," she said.

Ms Al Aslai said the Ministry coordinates with federal and local stakeholders to constantly monitor the sea and coastal environment, particularly water quality, and issues an immediate response in cases of red tides that cause fish and other marine species to die.

“The Ministry is currently working with its partners to develop a digital program to monitor sea water for phenomena such as the red tide,” she said.

Updated: October 4, 2019 05:32 PM

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