The cause of death of more than 1,000 trout and other fish species in a small river in Co Cavan remains unknown.
Inland Fisheries Ireland, the State agency responsible for the protection and conservation of freshwater fish and habitats, is investigating what it has termed “a significant fish kill incident” on the Crover river, a tributary of Lough Sheelin.
Officers from the Shannon River Basin District became aware of the incident late last Friday.
“Inland Fisheries Ireland estimates that there could be in excess of 1,000 juvenile trout killed in the incident, covering a 1.5km stretch of water,” it said. “Other aquatic species were also found dead, such as crayfish, lamprey, stone loach and invertebrates.”
While investigations into this fish kill incident were ongoing, Inland Fisheries Ireland said it was not in a position to confirm the cause.
Responding to the incident, the Lough Sheelin Trout Protection Association said the reported number of dead fish was likely to be an underestimate.
“This is the third major pollution incident on this stream within the recent past, including a major fish kill a number of years ago,” it said.
In recent times, it has invested in a rehabilitation programme on the river, installing pools, riffles and gravel to improve the habitat.
“This devastating pollution incident will have a serious negative impact on all environmental life including otters, birds and insects,” it said.
“It is deeply concerning that whatever poison killed the fish in the Crover stream could also have affected other users of the lake.”