A PRELIMINARY investigation of a fish kill on the Shannon indicates environmental causes rather than disease.
A team from University College Galway, along with ESB Fisheries Conservation staff, has been investigating the deaths of hundreds of bream on Lough Derg over the last few weeks.
A preliminary report to the ESB says no more fish are dying, but the monitoring is continuing.
It says there is no evidence a pathogenic bacterial or viral disease was immediately involved in the fish kills.
The survey also reports that overall, the large bream stocks in the lake have not been significantly damaged by the kills and that angling catches will not be "affected.
But the vice chairman of Scariff, Mountshannon and Whitegate Angling Club, Mr John Collins, said yesterday: "I don't believe pollution is the cause and I think it is most definitely a disease."
"Only one particular' size of bream is dying, the 3 1/2lb one. If it was pollution it would have killed: the other bream. This happened last year also and the same size of bream died. The experts said then it was stress related," he said.
Scientists are concerned about the lake's ecosystem and point out that various state agencies have been investigating the lough in recent years.
The problems of the lough, particularly those linked with increasing enrichment or eutrophication in the lake, are also well known to local anglers land environmentalists.
"However, as has been the case with several other major Irish lakes, solving Lough Derg's environmental problems is largely a matter of tackling complex sociopolitical issues rather than looking for a scientific panacea," the report concludes.