D(K)DSFB - Kirkcudbrightshire Dee River System

Galloway Fisheries Trust ~ Kirkcudbrightshire Dee Report

The Kirkcudbrightshire Dee is one of the largest river catchments in South West Scotland (1021 km2) and was, in the past, one of the major salmon fishing rivers in Scotland. However, catches have been perceived to be in decline. There are a number of factors which may contribute to this decline in salmonid numbers, which has also been reflected throughout many other West coast catchments. Although marine mortality is thought to be the principal contributory factor in the decline of these salmon stocks, the GFT have identified several other issues which are occurring to varying extents within the catchment of the Kirkcudbrightshire Dee.

Acidification ~ The GFT has concerns that parts of the Kirkcudbrightshire Dee catchment are suffering from acidification. The Water of Deugh and the Black Water of Dee are particularly vulnerable to low pH levels and have requently failed to meet the pH requirements for salmonids of the EC Freshwater Fisheries Directive. However, further downstream, the underlying geology alters to that of calciferous Silurian rocks, which helps to raise the pH values and reduce the resultant acidification problems. Acidification of these watercourses is aggravated by the presence of blanket coniferous plantations. During 1990, approximately 34% of the total catchment area was under forestry cover (Young, 1996). However, many sub-catchments have been more extensively planted. These plantations act as scavengers of airborn pollutants and, combined with a poorly buffering underlying geology, aggravate the low pH levels in some areas.

High levels of acidity are extremely detrimental to aquatic life. It is known for example that at levels of below pH 5.6, salmonid eggs fail to hatch, due to the inactivation of an enzyme required for hatching. This obviously has strong implications for the sustainability of the salmonid populations in some areas. However, acid emissions are falling and international agreements have been reached which should see the continued decline of this source of pollution. Furthermore, forestry interests now consult widely on new development plans. Despite these developments, it is likely to be some time before the acidification problems within some areas of the Kirkcudbrightshire Dee catchment begin to recover.

Hvdro-Electric Schemes ~ On the 10th May 1929, Parliament passed the Galloway Water Power Act (1929), which allowed the progress of the Galloway Hydro-Electric Scheme. The scheme incorporates the entire catchment of the River Dee and also the upper reaches of the River Doon, through the damming of Loch Doon. Through electro-fishing surveys, the WGFT have shown that the fish passes at Tongland, Earlstoun and Carsfad do allow salmon to access areas upstream of each dam. However, concerns exist that, particularly at the Tongland pass, adult fish are not always easily able to locate the entrance to the pass and exit the upper chambers. The fish are also particularly vulnerable to poachers in this area. Furthermore, there are concerns that kelts and smoults find it difficult to progress downstream through the Tongland Dam. Scottish Power, together with the WGFT, the KDDSFB and others are currently investigating methods which would allow improved access to migratory salmonids on their joumeys upstream and downstream.

Habitat Degradation ~ During previous years, the GFT have habitat surveyed a number of tributaries of the Kirkcudbrightshire Dee. The purpose of these surveys is to identify areas which suffer from habitat degradation and would benefit from specific remedial measures. Degradation of habitat may take many forms. It is essential that ascending spawning fish can run unhindered up tributaries, to utilise available spawning habitat. Obstacles may take many forms, such as natural obstructions, e.g. waterfalls and man-made obstructions, such as dams. Additionally, debris may accumulate against some forms of obstruction and result in severe bankside erosion, as the watercourse attempts to find an alternative route around the obstacle.

There are various methods by which the diversity and quantity of suitable habitat can be restored within a degraded watercourse. Rock placement instream will create small pools and riffles and can also be used to provide bankside fish cover. The insertion of stone weirs and deflectors will redirect flows and encourage pool and riffle sequences. Willow wands placed into bankface and bankside will quickly grow and, in addition to helping to stabilise the banks, will provide cover for fish and contribute woody debris to the instream environment. Too many bankside trees can result in overshading of the watercourse. The resultant lack of light can limit primary production and cause a consequent lack of food for salmonids. Cutting back or coppicing these trees will allow greater light penetration through the canopy.The GFT, working in partnership with the D(K)DSFB, are currently undertaking a three year bankside and instream habitat improvement project to help address the problems of degraded habitat. This work will be partially funded by Scottish Natural Heritage.

Signal Crayfish ~ The signal crayfish is not a native species within Scotland. However, they were introduced into the Dee in the belief that they would supplement the native fisheries. The Signal Crayfish is a voracious carnivore and will feed on salmonid fry and parr. While the crayfish may be preyed upon itself by salmon and trout whilst it is moulting and therefore vulnerable to attack, this occurs during limited periods of time. Additionally, the crayfish resides under stones, amongst roots and under overhanging banks, which brings it into direct competition with fish, especially 1+ individuals, for shelter and cover.

The Galloway Fisheries Trust continue to carefully monitor the catchment of the Kirkcudbrightshire Dee and will maintain its role in respect of both research and management of this valuable natural resource. The GFT liases extensively with organisations such as Forest Enterprise, Scottish Natural Heritage, the Scottish Environment Protection Agency, Scottish Power and others. The Trust is also contributing to the development of the Ken-Dee Catchment Management Plan, which is being developed as a result of recommendations made by the Local Biodiversity Action Plan. A Salmon Management Plan will also be formulated by the GFT, which will present much of the data that the GFT possess on the catchment and will also formulate a comprehensive strategy for its management on a rolling five year programme.