Castlebar River - a Good News Environmental Story

The Castlebar River is a testament to modern environmental protection. It has gone from being a pollution blackspot in the early 1980s to being potentially one of the finest salmon and trout rivers in the country. The final steps in its rehabilitation are currently in progress. The building of the new sewage works in 1983/84 eliminated the awful organic pollution from the town's sewage and industrial plants (the old bacon factory especially).

A problem of eutrophication remained, however, until the sewage treatment works was upgraded to include a phosphate removal stage. Thanks to the Castlebar Urban District Council and Mayo County Council this plant began operating in June 1997. Its main benefit will be to eliminate the masses of green blanket weed which choked the river bed and sucked the oxygen out of the water at night time. The low oxygen levels at night prevented the upper river section from holding trout in any great numbers because they need a lot of oxygen to survive. The blanket weed algae will no longer be able to flourish due to lack of phosphate and as a result water oxygen levels will no longer fall dramatically at night. Thus, trout will be able to survive in the upper sections of the river from now on.

The second important improvement is a physical one - a major falls near Turlough Village about five miles downstream of Castlebar which had effectively blocked any salmon from getting up as far as Castlebar Town. The North Western Fisheries Board and the Central Fisheries Board have recently cut a very natural looking meandering channel through the long stretch of bedrock falls in order to allow fish to migrate upstream.

With the help of an EU-aided scheme, they have also replaced a lot of the river bed material - stones and gravel - which was removed during the Moy drainage scheme in the 1960s. This will provide better spawning for salmon and trout as well as nursery areas for small fish and they have created some deeper pools as holding areas for larger fish. In other rivers this has increased the number of salmon three to fourfold and the Castlebar river has even greater potential than most rivers in the Moy catchment.

All in all this is a good news story - we can now expect salmon to reach Castlebar Town - perhaps we will be able to watch salmon swimming under the bridges and leaping the weir into Lough Lannagh. Therefore we should all try to prevent direct pollution of the Castlebar River in the town itself and no throwing rubbish off the bridges please! The next few years will see salmon and trout establish themselves in the upper Castlebar River in significant numbers providing an example of what can be done in the area of environmental protection.

Pollution reports to the Fisheries Board (096-22623), Mayo County Council (094-24444) or the Environmental Protection Agency in Castlebar (094-21588).

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Mayo Editorial Services mayoedit@iol.ieCopyright © CIAT. Created: 12 July 1997 Updated: 24 August 1997