Belfast Telegraph

Monday 20 October 2014

Pollan: Climate change may mean the end for Ireland’s rarest fish

Ireland’s rarest fish is under threat from climate change, scientists are warning at a major conference in Belfast this week.

The pollan, found in only five loughs in Ireland, could dwindle even further if our waterways heat up due to global warming, says Dr Chris Harrod, convenor of the Fish and Climate Change conference at Queen’s University.

The five-day conference brings together around 140 fish biologists and fish managers to uncover how climate change is affecting global fisheries.

Dr Harrod, a lecturer in fish and aquatic ecology at Queen’s School of Biological Sciences, says it is already having an impact on loughs, rivers and oceans, with dramatic changes in fish stocks.

“Climate change should not be underestimated. Although the decline in many valuable fish stocks is largely a reflection of fishing pressure, fluctuations in some exploited warm-water species, such as the sardine, have been closely related to changing water temperature,” he said.

“With more people keen to follow a healthy diet and exploit these healthy sources of food, it is important to understand the impact of these changes on our diets.”

Fish facing particular pressure include Northern Ireland’s glacial relics — cold-water fish such as Atlantic salmon, Arctic charr and pollan. The latter is Ireland’s most threatened fish.

“As our waters heat up, these are under particular threat. Populations that depend on these fish and value them for their biodiversity will also have to adapt to change,” Dr Harrod said.

“Many of our species can be considered to be losers, but there will be some winners. These include non-native and ‘introduced’ freshwater fishes, such as the roach that will thrive as waters warm up, increasing their impact on lakes such as Lough Neagh.”

Eels, key to Lough Neagh and its surrounding communities, are likely to grow bigger as waters get warmer. However, changes to marine currents will mean a reduced supply of juvenile eels from the Sargasso Sea to Irish shores.

Dr Harrod said the pollan remains something of a mystery.

It is found only in Lough Neagh, Lough Erne, Lough Ree, Lough Derg and Lough Allen and populations crashed after World War I and in the 1990s.

Cod stocks in the Irish Sea have dwindled, not only because of overfishing but also rising sea temperatures. Warming seas have also been implicated as one of the reasons for vanishing sand eels in the Irish Sea. It’s thought this loss of food source may be behind the crashes of seabird populations on Rathlin in recent years.

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