Study finds smolt rearing has few adverse effects

A 10-year scientific study of a lake on the Connemara bog complex has found no significant environmental changes as a result of smolt rearing for fish farming.

The findings on a lake near Clifden, Co Galway, in a proposed Special Area of Conservation (SAC), suggest that west of Ireland lakes may be more suitable for fish cage culture than previously thought, said Dr Brendan O'Connor, of Aqua-Fact International Services Ltd.

A separate study of the environment by Aqua-Fact found a low level of organic waste on the sea floor and in the water column in many salmon-farming bays.

Aqua-Fact's freshwater environmental study focused on Lough Fada, in the Connemara bog complex, which has been used for 10 years to produce smolts for marine-based salmon farms. Fish are put in the lake in September and removed in March. The lake is then left fallow.

Dr O'Connor's team reviewed water quality data and compared the phytoplankton ecology and water chemistry in the lake to Lough na mBreac Mor, which has no fish farm, over a year. It looked at additional water chemistry surveys in nearby lakes.

He told participants at a recent conference in Galway run by Dr Maura Hiney, of NUI Galway's fish disease group, that levels of phosphorous in Lough Fada exceeded notional upper levels set by the Department of the Marine and Natural Resources where there were no fish in the cages.

He attributed the healthy environment to factors such as the predicted flushing rate of the lake, the positioning of the cages close to the outflow stream and the six-month fallow period.

Meanwhile, the Green MEP for Dublin, Ms Patricia McKenna, has called on the Minister for the Marine and Natural Resources, Mr Fahey, to place a moratorium on all new fish-farming ventures in two bays in the south-west, Bantry and Kenmare. "By giving in to almost every licence application the Minister is threatening the livelihood of many smallscale, environmentally friendly tourism ventures," she said.

The second symposium on Fish Farming and the Environment is at www.aquaenvironment.com lsiggins@irish-times.ie