INTERFERENCE WITH river systems is causing serious environmental damage in the southwest, according to the annual report of the fisheries body with responsibility for most of Cork and Kerry.
The spawning and nursery grounds of salmon in particular were damaged by the removal of sand and gravel, said the report by the South Western Regional Fisheries Board.
The report records how Kerry County Council was responsible for a major fish kill during the year and was prosecuted by the fisheries board.
A meeting of the board heard how scores of complaints were made by members of the public about discharges into waters by agriculture, industry and local authority sources during 2007.
In all, 278 environmental complaints were investigated by the board. These were made by the public, fisheries officers as well as anglers and board members.
The region has some of the best angling rivers in western Europe for sea trout, salmon and brown trout and is popular with overseas anglers.
There were several incidents involving the removal of materials from rivers and streams throughout the region affecting spawning and nursery grounds of salmon in particular, said Dr Patrick Buck, assistant chief executive of the board.
The interference had also affected river bank habitats.
"This is a big issue from a biodiversity point of view. It seriously affects rivers," Dr Buck said.
He also referred to the damage done to rivers by land reclamation, building and other drainage works.
Arterial land drainage and other works meant water now "poured" into rivers, rather than soaking from the land, resulting in the washing away of river banks .
Taking too much water from rivers was also an issue, he said.
Slurry and silage spills into rivers, lakes and streams continued to be a problem, said the annual report.
Kerry County Council was responsible for a major fish kill in the Mall, a small river flowing into Dingle harbour. Some 2,000 brown trout - practically all of the river's trout population - and eels were wiped out when a chemical from a council-owned water treatment plant spilled into the river last June.
The council was prosecuted by the board. It pleaded guilty and said the spill was a one-off occurrence. The case was struck out at the Dingle District Court last month.
In June, brown trout and young salmon were killed by a suspected herbicide on the Bride river, a tribute of the river Lee, in Cork, and on the Brewery river near Dunmanway a suspected water-treatment chemical is thought to be responsible for killing about 200 young salmon last September.