July 2001 Water Quality Monitoring Report

Release date: Tuesday 10 July, 2001

"The ecological integrity of the flora and fauna in the country's lakes can provide an early warning system for impending problems in lake water quality and when used in conjunction with systematic analyses of water chemistry and monitoring of nutrient inputs, help in the protection of Irish lakes", according to Dr. Kieran McCarthy of NUI, Galway's Department of Zoology and author of a new environmental report. The results of the three-year research programme on six large western lakes (Loughs Carromore, Conn, Cullen, Carra, Mask and Corrib), undertaken by NUI, Galway in partnership with the Central Fisheries Board and Aquafact Ltd, have just been published by the Environmental Protection Agency (EPA).

The Report is entitled, Investigation of Eutrophication Processes in the Littoral Zones of Western Irish Lakes.The report describes research on a variety of aspects of the lakes, including their planktonic algae, submerged plants, aquatic insects, sediments, water circulation and fishes. The studies have shown that though localised signs of pollution were detected in all the water-bodies, and significant enrichment was noted in Loughs Carromore, Conn and Cullen, the lakes of the Corrib catchment have so far escaped the more serious effects of eutrophication that can be noted in most of Ireland's other large lakes.

The main conclusions of the report were:

• Though water quality in the western lakes was generally better than some previous press reports suggested, three of the six lakes studied showed signs of eutrophication and localised signs of enrichment were evident in all of them.
• Many unique features of the lake ecosystems are being lost (e.g. Arctic Char are now gone from Loughs Conn and Corrib), due to the combined effects of environmental deterioration and the introduction of species not native to the lakes.
• Conservation of the unique plant and animal communities of the lakes is important and maintaining their ecological integrity can serve to ensure their use for domestic water supply, angling and other recreational purposes.

Dr. McCarthy expressed concern that introductions of non-native aquatic invertebrates and fish parasites could adversely affect the many interesting species of aquatic plants and animals that are typical of the lakes. "Studies on these unique elements of the lakes' communities are important and ensuring their survival might be one of the best ways of guarding the lakes against early stages of enrichment and other undesired environmental changes", he said.

Welcoming the continuing support shown by local anglers for the University's freshwater research programmes, Dr McCarthy pointed out that the role they played in reporting pollution events and other unwelcome changes to our lakes was a vital one. "The long hours that anglers spend on or near the lakes or their in-flowing streams and rivers, provides them with ideal opportunities to observe fish and wildlife habitat conditions", he said. "However, anglers' contributions to lake water quality monitoring could be extended and more effectively linked to the work of the fishery boards and long-term EPA surveys. Anglers could systematically record localised algal blooms and other visible evidence of fish habitat degradation. They can also be effective environmental guardians by helping to keep out unwanted species introductions". Irish anglers have in recent years been active in preventing the spread of the zebra mussel from the Shannon lakes to the great trout fishing lakes in the West. Ireland's lakes are now home to an increasing variety of alien species, like North American crustaceans and Japanese fish parasites. Some of these species introductions may in time cause unexpected changes in the lake ecosystems, to the detriment of fisheries and maybe even, like the Shannon's zebra mussel invaders, to water quality parameters.

The report also indicates that dense coarse-fish populations can affect lake ecology and strongly recommends that the unique fish community of Lough Mask deserves special protection from further fish species introductions. Unfortunately, roach have found their way from Lough Corrib to Lough Mask in the past few years and concern is being expressed about the effects they may have on the currently healthy char stocks there. Also, roach and gradual environmental change may result in the loss of other unusual inhabitants of the deep cool clear waters of the lake. Lough Mask is home to such species as the blind white crustacean, Niphargus kochianus hibernicus, a creature more typical of subterranean waters and not found in any other Irish lake bottoms. Also found in the lake are rare insects, like the non-biting midge Corynocera ambigua, that are thought invaded its waters soon after the retreat of glacial ice sheets over 10,000 years ago.

Studying and attempting to protect these interesting lake dwelling invertebrates may, according to Dr. McCarthy help focus attention on the need to guard against even apparently minor changes in the ecology of the lakes.

The main recommendations of the report were:

• Nutrient inputs to the lakes and the variations in chlorophyll levels, and other water quality parameters, should be monitored more systematically.
• A more comprehensive ecological approach to monitoring the lakes should be adopted, involving new biomonitoring techniques discussed in the report.
• should be paid to all adverse environmental changes, not simply nutrient enrichment.
• Avoidance of species introductions to the lakes, including transfers of coarse fish from other parts of Ireland, is important.
• Research on the unique elements of the flora and fauna of the lakes is recommended as these ecologically sensitive species may provide early warning signs of environmental change not yet affecting more abundant and widespread aquatic plants and animals.

This project was part-funded by the European Regional development Fund through the Operational Programme for Environmental Services, 1994-1999.

The NUI, Galway research team has recently started a new inter-disciplinary study of Lough Corrib involving co-operation between the University's Departments of Zoology, Botany, Chemistry, Hydrology and Geology, funded by the Higher Education Authority, as part of a major programme of environmental research linked to the establishment on campus of a new Environmental Change Institute. The recent purchase of a new research boat for the Lough Corrib study is, according to Dr Mc Carthy, an indication of the university's commitment to long-term studies of the lakes in the Corrib/ Mask system. "NUI, Galway is uniquely located, among Irish universities, for such limnological research, as its riverside campus is just a few miles down stream from Lough Corrib and research workers can easily travel directly from their laboratories to the lake. Use of the new boat will enable researchers to further develop the new lake monitoring protocols recommended in their report now released by the EPA and to enable young researchers to learn about the intricacies of freshwater ecology on one of Ireland's most beautiful water-bodies", he said.

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