Video: Mystery behind massive fish-kill

Government scientists are scrambling to unravel the mystery behind a massive fish kill on one of Tyrone’s most popular fishing lakes that angling experts estimate left up to 10,000 fish dead.

Staff from the Department of Culture, Arts and Leisure (DCAL) have confirmed that thousands of fish were affected at Brantry Lough last week, including stocked trout, perch and roach, in an unprecedented die-off that threatens the future of the fishing lake

Angling expert Tommy Conlon

Angling expert Tommy Conlon

On Thursday, hundreds of dead fish were still littering the shores of the lake, horrifying anglers and passers-by.

Staff from the Department of Culture, Arts and Leisure (DCAL) removed the rotting bodies in plastic bags, and have been testing oxygen and temperature levels throughout the lake.

DCAL have now discounted the theory that a difference in temperature between the tanks in which the fish were transported and the lough itself could have contributed to the kill, which was one of the worst ever seen in the area.

However, local fishermen have claimed they noticed the first signs of trouble weeks ago, and had warned the Fishery Department that a catastrophe was about to happen.

Angling expert Tommy Conlon, who has been writing about fishing for more than 30 years, said it was ‘absolutely shameful’ to see the dying fish gasping for air.

“I first warned DCAL about the situation almost two months ago. We have far too many perch in the lake, and the overcrowded conditions risk the future of the stocked trout.

“Unfortunately, I have now been proved right. It is my belief that the fish were killed because of a combination of high water temperatures and a lack of oxygen, caused by the overcrowding.

“The trout have been feeding on the perch fry which is breeding like wildfire, and have no interest in the fly lures set by anglers.

“Where once we had dozens of anglers fishing here every evening, you would not see that number across the week. Now the whole future of the lake is under threat.

“DCAL will have to take a long, hard look at its plans for this lake, and how it plans to make it a success again.”

Another fisherman claimed to have observed fishery staff stocking the fish with trout several times in the past number of months.

“It was clear to me and other fishermen that the trout weren’t behaving as they should”, he said.

“They were acting strangely and seemed to be staying at the bottom of the lake rather than coming up to feed on flies.

“They were obviously suffering and the water quality was deteriorating.”