Climate change 'could devastate trout and salmon rivers'

Ireland’s world famous trout and salmon rivers could be devastated by climate change, experts warned today.

The lucrative waterways – worth tens of millions of euro a year to the economy - will be hit with double extremes of winter floods and near droughts in the summer reducing them to sluggish trickles.

Met Eireann said its research forecasts that some of the country’s best known rivers could shrivel to half their current size during the driest months of the year.

Fisheries experts also fear the knock-on effect could see valuable spawning grounds severely damaged.

The Central Fisheries Board said the €30m trout and salmon angling industry is under serious threat if rivers suffer dramatic change.

“The key on the negative side of things would be how high the water temperatures get in the summer,” a spokesman for the board said.

“The greatest concern would be low flow levels in the summer because salmon and trout are cold water fish.”

They spawn between November and February and high water during that window would help and may even boost numbers reaching spawning grounds in headwaters. But flash floods could also ruin these beds, kill deposited eggs and cause massive erosion.

One of the worst affected rivers is likely to be the Suir, which runs through Tipperary and Waterford, which could slow to less than half its current size between June and August.

But heavy and persistent winter rains could swell rivers by between 10% and 20%.

Ray McGrath, head of Met Eireann research division, said more research was needed to assess the full impact.

“In the winter months the river flows are likely to be above normal so there’s much greater risk of flooding,” he said.

“In the summer months you have the opposite happening because perhaps the situation will be drier over Ireland – less rainfall and less run off and the rivers will be more sluggish.”

“The River Suir is already a bit iffy as regards flooding and that is something that is going to be more closely studied in the years ahead.”

The Moy, which attracts anglers from around the world, could be halved at the height of summer and swell a tenth from January to April.

The Blackwater, already prone to serious flooding, could carry a fifth more water in January but drop to almost half its average level between June and August.

The devastating effects of the swollen river were felt last month when both Fermoy and Mallow, Co Cork, were left with a €10m clean-up bill after the worst flooding in decades.

Relief works are planned for the two towns to take floodwater out of the valley faster.

The Suir, which is also considered a flood-risk system, could swell by a tenth from October right through to April, putting thousands of homes and acres of valuable land in danger. And again the summer would see it dry to half its average.

It is widely accepted that Ireland will experience temperatures up to 1.5C higher in 2060 with wetter winter months and drier summers.

Met Eireann plans further studies with the support of scientists at UCD.