Tuesday 26 March 2019

Mystery disease threatening to wipe out fish in famous Irish lakes believed to be deadly 'koi sleepy' virus

Fish have been mysteriously dying at The Lough in Cork
Photo: Google Maps
Fish have been mysteriously dying at The Lough in Cork Photo: Google Maps

Ralph Riegel

Marine biologists now believe a mystery disease which has threatened to wipe out fish stocks in several famous Cork lakes is a rare virus deadly to carp.

Inland Fisheries Ireland confirmed that scientists at the Fish Health Unit at the Irish Marine Institute have advised that the sample carp taken from The Lough and Belvelly Lake in Cork have all tested positive for Carp Edema Virus (CEV).

CEV is a poxvirus which causes a disease known as ‘koi sleepy disease’ in both koi and common carp.

However, experts warned that their investigation remains ongoing.

"While tests are ongoing and further tests are carried out on the CEV detected, this is being treated as a ‘suspect positive’ and is not confirmed as the causative agent of the mortalities until all tests have been completed," an IFI spokesman said.

IFI have now advised that strict bio-security protocols including non-fishing orders and careful equipment contamination be adhered to so as to prevent any further outbreaks.

All dead fish are being carefully removed from the two Cork lakes and are being disposed of in a secure manner.

Angling remains suspended at both locations as well as Inniscarra and Carrigadrohid Reservoirs.

The investigation was accelerated after reports that fish were dying in a lake outside Cobh - just days after fish mysteriously started dying in the famous Lough in Cork city.

Fears had mounted that the mystery infection could spread to other valuable waterways.

IFI are liaising with Cork City Council, Cork Co Council and expert marine biologists at University College Cork (UCC) and Cork Institute of Technology (CIT) in a bid to confirm and contain the infection.

Fish first appeared sick and dying at The Lough last week.

A total of almost 400 carp have since been found dead or dying.

However, fish similarly sick and dying have been found at Belvelly Lake outside Cobh.

Those fish appear to have the same type of illness at the dead carp in The Lough.

IFI official Sean Long said the matter was being taken very seriously.

"There is a white fungal growth appearing on the scales on the side of the fish," he said.

"That could be a secondary issue or it could be part of the problem."

Angling groups expressed alarm at the implications of the mystery illness spreading to other waterways used by recreational fishermen.

Anglers have now been asked to carefully clean and disinfect any equipment used in either The Lough or Belvelly Lake.

All fishing on The Lough has now been suspended.

Both Inniscarra and Carrigadrohid Reservoirs are off-limits to fishermen to prevent contamination spread.

Nine years ago, birds began mysteriously dying at The Lough.

The deaths began in July 2009 and involved dozens of swans and ducks.

Those deaths were later blamed on a form of botulism linked to toxins being stirred up from the mud at the bottom of the lake and connected to the large quantities of bread being thrown into the water for wildlife to feed on.

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