The chief executive of the Shannon Region Fisheries Board said yesterday there were no fish remaining in the spawning grounds affected by the landslide in the Stacks Mountains in north Kerry last weekend.

Thousands of young salmon and sea trout had been wiped out in the tributaries of the Smearlagh river.

However, the full effects of the landslide on the Smearlagh and Feale rivers may not be felt for five to 10 years, because of the migratory pattern of the life-cycle of the fish.

Eamon Cusack, chief executive of the board, said the landslide was particularly unfortunate in that these rivers had managed over the years to retain good, healthy stocks of salmon and sea trout.

The Smearlagh in particular had good spawning stocks of sea trout.

"These are nursery streams," Mr Cusack said of streams such as the Glashoreag which feed into the river and which were overwhelmed by the chocolate-brown slick of peat resulting from the landslide which began on Friday. There were no fish in these smaller rivers now, he said.

He feared that the gravel beds of the water courses would now be so overlain with silt that the salmon and sea trout that return in October and November would not be able to spawn.

Both of the larger rivers were in flood at the time of the slide and this had helped minimise the damage, he added.

Already thousands of euro worth of fish stock has been lost.

The cost of cleaning the rivers and returning them to their original state could run to hundreds of thousands of euro.

It was unlikely there would be restocking as the scientific advice was that naturally regenerated fish were healthier.

Mr Cusack warned that further soil movement could be expected if more rain fell.

Water tankers were supplying some householders who had no water supplies yesterday and all householders in north and east Kerry were asked to conserve supplies.

Boil water notices were issued to some. One of the two reservoirs had emptied and Kerry County Council was seeking alternative supplies.

The council's water services executive engineer, Brian Sweeney, said yesterday the situation was not as dire as he had expected on Sunday when the whole of northeast Kerry was expected to be without water from yesterday.

The second reservoir and treatment system which draws on the Feale, 10 miles downstream from the landslide, was able to operate, though not at capacity.

Mr Sweeney warned that the threat to water supplies for up to 30,000 people would remain for some time.

Council workers have managed to build a dam to divert the landslide of peat and bogland, which has now reached 1½ miles long, from further damaging rivers.

The clean-up costs will be "significant" after bridges, roads, telephone poles and other infrastructure were damaged as well as houses cut off, a council spokesman said.

Council staff will be assessing the stability of the area and carrying out an investigation into the causes.

Residents have called for a change in the county council development plan which has designated the Stacks area for wind farm development.