Climate change may be one of the main causes of a serious decline in native eel stocks, according to a research team at NUI Galway.
Evidence suggests the decline in juvenile eel populations arriving in European coastal zones is due to climatic effects on ocean currents.
The research team, led by Dr Kieran McCarthy of NUI, Galway's department of zoology, believes this may also be having an impact on salmon and other migratory fish.
Young eels, that have swum thousands of miles across the Atlantic on the Gulf Stream, migrate annually to Ireland's rivers in spring. A decline on the Shannon has been recorded in recent seasons. Last year fishermen blamed the ESB, manager of the river, for the collapse of the fishery on the waterway.
The number of juvenile eels trapped at Ardnacrusha for stocking has dropped from a peak of seven tonnes in 1979 to an average of less than half a tonne in the past decade.
Numbers captured leaving the river as mature silver eels have also declined, from an average of 28 tonnes annually in the 1980s and early 1990s to an average of 10 tonnes since the mid-1990s.
Water quality problems and the spread of parasites have contributed to the fall in stock levels. Serious declines have also been observed elsewhere in Europe.
An international management plan may be required for sustainable exploitation of the stock, according to scientists who have discussed the issue with colleagues from Northern Ireland and other European states, including Sweden, Germany, Belgium, France and Portugal.
