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Dáil Éireann díospóireacht -
Wednesday, 29 May 1996

Vol. 466 No. 2

Ceisteanna—Questions. Oral Answers. - Lough Derg Fish Kill.

Michael Smith

Ceist:

11 Mr. M. Smith asked the Minister for the Marine whether he has ascertained the cause of dead bream in Lough Derg; if he will commission a health status study on coarse fish in that lake; the immediate action, if any, which is necessary in this regard; and if he will make a statement on the matter. [11249/96]

I share the Deputy's concern about the recent mortality of bream in Lough Derg, not least because of the valuable contribution which coarse angling tourism makes to the Shannon catchment. The Department and I have been in ongoing contact with the Shannon Regional Fisheries Board since the problem emerged at the end of March. Investigations carried out by board staff at the time confirmed numbers of dead bream in various locations in Lough Derg. In liaison with the ESB, which owns the Shannon Fishery, the board arranged for an immediate scientific assessment to be undertaken by UCG's fisheries research team. UCG has been working over the past two years on a wide ranging study of coarse fish stocks funded by the ESB.

There are a number of unexplained aspects to the mortalities, notably the fact that only mature bream are involved and other fish species, such as salmon and trout, which are usually more sensitive to changes in the ecological conditions of waters, have been unaffected. Other freshwater coarse fish in Lough Derg were apparently unaffected. The bream mortalities continued for about three weeks and had ceased by the end of April.

Scientific investigations are continuing and there are no definitive answers as yet as to the cause of the mortalities. Preliminary findings have indicated extreme gill damage but at this stage no conclusive evidence of associated disease has emerged. Water quality in the lake was examined at the time of the fish kill and found to be generally good. Further investigations into other possible environmental factors, including sediment analysis are ongoing. The jury is still out on the cause of the mortalities. I expect a final report in the matter within a few weeks.

I am advised that preliminary fish population survey data indicate that the very considerable bream stocks in Lough Derg have not been measurably affected by the recent mortalities. These, though worrying, were quite low relative to overall stock levels. At this stage there is no reason to believe that angling catches will be adversely affected during the coming season.

The current problem serves to underline the need for sustained action to address ecological and fish health problems in Lough Derg and throughout the Shannon catchment area, in the interests of protecting and enhancing the valuable coarse fish resource and the ecosystem which supports it. The Shannon Regional Fisheries Board has been concerned about the management of coarse fish in the Shannon system for some years. The research project being undertaken by UCG, which was commissioned by the ESB at the board's request, was a first step in taking action in this area. That now needs to be followed up on a number of fronts.

As an immediate response I have requested the Department, the Shannon Board, the Central Fisheries Board, the ESB and the Marine Institute to prepare a report and to recommend proposals to progress a coherent strategy for the management of the national coarse fish resource. They have proposed, as an initial step, the engagement of outside expertise to conduct a study of coarse fish stocks and problems experienced in recent years and to recommend on management strategies and future research and fish health programmes.

An integrated and systematic approach to the conservation and management of our valuable coarse fish stocks is required and I am fully committed to working with the Shannon Board, the ESB and all relevant agencies and Departments in putting in place the necessary measures to achieve this aim. I expect to receive shortly the detailed collective proposals from the Department, the board and the other agencies which will be considered and taken forward as a matter of priority.

While appreciating the Minister's decision to undertake a health study of coarse fish in Lough Derg and other places, I find the tenor of his reply very complacent. I do not know whether he had an opportunity of seeing the spectacle of thousands of dead bream decaying on the shoreline. That this could not affect tourism and other aspects of the development of that lake is inconceivable. The Minister should speed up as much as possible the investigation of the unexplained aspects of this matter. While other species were not affected, it is frightening that something like this can continue for this length of time without its causes being known. We could perhaps be faced with an even deeper problem tomorrow. I am extremely anxious that the health study be undertaken so that within a very short time we will not be faced with problems affecting other species. After two months we will still do not know the cause of the deaths of these thousands of bream.

My response was far from complacent. Immediately the information became available to me and my Department a study was sought from University College Galway and its results made known to us very speedily. It might be worth quoting from it for the benefit of Members:

Fish pathology investigations by the UCG-based Aquatic Veterinary Group (Bioresearch Ireland Ltd.) showed that the dead and moribund bream, as well as gill netted apparently healthy fish in upper Lough Derg, showed extreme gill hyperplasia and necrosis, not associated with infectious disease. This led to the conclusion that chronic exposure of the fish to unfavourable environmental conditions had contributed significantly to the deaths of the bream. The immediate factor(s) involved could not be established since the tissue response was a generalised one which could be attributed to the effects of either soluble or particulate irritants.

Later the report went on to state:

Lough Derg water quality was generally found to be good, with a vertically mixed well oxygenated water column.

Following that report scientists in UCG are carrying out a further study of the sediment in Lough Derg to establish what occurred there. There were a number of unusual features to it. The larger, older bream only were affected by this incident, smaller ones were not. Other fish species were not affected at all. Because of this incident and the necessity to concentrate some further research activity on coarse fish, I have asked the Shannon Regional Board, the Central Fisheries Board, the Marines Institute and other agencies, including the ESB, to prepare a report for me. They have given me an initial indication that it will be necessary to secure outside scientific assistance to enable them to carry out some studies on our coarse fish stocks, which will now proceed. Whatever measures are deemed necessary to protect our coarse fishing resources will be taken.

Nobody in this House wants more than I to believe that the quality of water in Lough Derg is such as to safeguard fish life and promote our tourism industry. Because of investment by many local people there I genuinely want to believe that, but I am quite frightened that something like this can continue for so long and, even at this stage, we cannot ascertain the reasons. Can the Minister not understand that as long as the general public and visitors go there and discover this problem, there will be a total lack of confidence in the ability of that lake to sustain employment and tourism?

I want to make it clear that angling on Lough Derg will not be affected. I am sure Deputy Smith will agree that what is required is a definitive scientific view of what caused this fish kill. We had better await that rather than rush to a conclusion which might not be substantiated subsequently.

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