Northern Ireland's Glenarm Organic Salmon is taking precautionary measures against a possible rise in jellyfish numbers. (Photo: StockFile/C. Reports)

Officials on alert for blooming jellyfish

UNITED KINGDOM
Tuesday, September 22, 2009, 03:40 (GMT + 9)

Northern Ireland’s sole salmon farm, Glenarm Organic Salmon, is cautiously employing extra measures against jellyfish to prevent attacks like that of 2007, which destroyed GBP 1 million (USD 1.62 million) worth of salmon. Meanwhile, wildlife experts claim that low numbers of jellyfish currently inhabit coastal waters.

No dangerous population boom has been detected since 2007, said marine biologist Gary Burrows of the Northern Ireland Environment Agency (NIEA), Belfast Telegraph reports.

“Some coastal councils have done beach surveys and there are very few jellyfish,” he said.

But the animals are always present, he said, such that swimmers should always stay alert. Even so, no stingers were observed at Portballintrae or Whiterocks and only small numbers at Coleraine or Portrush.

“There are no indications of any more large blooms, but anything can change with the next tide,” Burrows noted.

“The Pelagia noctiluca are small in size, have a globe-shaped bell, a warty appearance and are an overall purplish colour […] Its sting is powerful and can produce a very severe reaction,” he commented.

Commonly known as “mauve stingers,” these animals have appeared in "significant" numbers lately at Whitepark Bay in Co Antrim. Climate change and the overfishing of natural predators such as tuna and swordfish are the latest assumed culprits for the expanding population of jellyfish in the North Atlantic Ocean, he said.
 
“They appear to be increasing for the simple reason that jellyfish reproduce in bigger numbers in warmer seas. Some of their predators are found in much smaller numbers as well,” he said.

NIEA informed the Department of Agriculture and Rural Development's Fisheries Division about the jellyfish last week. It said it will continue to monitor any developments in population, the Belfast Newsletter reports.

"Support to scientists studying jellyfish aggregations will continue through the provision of samples and periodic plankton trawls onboard the NIEA research vessel," Burrows affirmed.

Back in 2007, billions of jellyfish covered an area of up to 10 sqmi and 35 ft in depth around Glenarm Organic Salmon. The jellyfish dyed the waters red and suffocated over 100,000 caged fish.

By Natalia Real
editorial@fis.com
www.fis.com

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