David Norris (Independent) | Oireachtas source

I am advised by Mr. Nicholas Grubb of Dromana House, County Waterford, that he has isolated a problem concerning salmon breeding in Irish rivers. Today, I am suggesting an environmentally friendly solution to this problem.

Ten years ago the Irish offshore drift net salmon fishing was ceased as a result of complaints from our European neighbours, which I find rather entertaining given the depredation they cause to Irish fish stocks. There was a period of cessation of approximately four years following which the total allowable catch system was introduced, which is based on the stock strengths of various rivers. One would imagine this would result in a considerable increase in fish stocks and a boost to the tourism industry in the context of angling but the reverse has happened in that catches have disimproved. There are a number of reasons given for this, the official one being that there has been an escalating level of sea losses, with smolt going out to the north eastern Atlantic feeding areas not returning in the numbers expected.

According to the fishery scientists, survival is down to around 5% from a level of 40%, which is fairly disastrous. There are five reasons advanced for this, including: climate caused ocean temperature changes, which has resulted in the sand eel and krill moving further north, to which the fish have not yet adjusted; the mass harvesting of krill and sand eel to provide commercial sources for cat food, etc.; salmon being inadvertently caught by trawlers fishing for other species; damage to smolt as they exit the river systems caused by a myriad of sea lice lava coming off the sea cages of the fish forms in the west coast inlets; and attacks by flocks of cormorants, the results of which can be disastrous.

Are these really the reasons for the decrease in the survival rate? A major factor could be that we are not sending out sufficient numbers of strong smolt in the first instance. There are a series of social changes that have affected this, including, for example, the development since the 1950s of rural electrification, gas cylinders and Bord na Móna peat briquettes. In the past in rural areas people went out and gathered firewood from the banks of small rivers and streams, thereby leaving the riverbanks, which were considered public domain, clean. This meant that thousands of miles of small tributaries of the main rivers were open to sunlight and became highly productive nursery areas for trout and salmon. However, the vast majority of these small streams are now completely tunnelled over by Alder and other trees.

It is easy to identify the rivers that are ecologically deficient. They are the ones that have no ranunculus growing alongside. Ranunculus is a long green stringy weed which, if one pulls it up out of the river, will be teaming with lice. Dr. Martin O'Grady, who carried out academic work in this area, reported in 1993 that this over-shadowing of streams reduces their breeding potential by 70%. That is what he reported over 20 years ago. The situation has worsened since then and has been exacerbated by ill-thought out REP schemes and so on. This reputable academic survey concludes that tunnelling reduces breeding potential by 70%. The result of this is the phenomenon of main channel spawning whereby fish are being driven out of the small tributaries and forced to breed and spawn in the main channels. Spawning in the main channels leads to over-competition, excess predation and smaller, weaker smolt being produced, which are easy targets for sea lice infestation. This may also explain why in many Irish rivers the vast bulk of the returning fish are now entering the rivers of origin later in the season.

I now come to the solution. There have been a number of pilot projects involving manual rehabilitation of degraded stretches of dendrite but only a certain amount could be done by hand. However, enough has been done to demonstrate a massive increase in productivity of the stretches concerned. Work on the Kilmanaghan River near Clonmel is a case in point. The reality is that such rivers probably each have 1,000 km of good nursery streams such that an 0.1% improvement will not impact hugely on the situation. The situation involving the farmers, in terms of their being under the umbrella of REPS and AEOS, and as such required to fence-off rivers and streams, makes the problem worse. While this is being done with the best of intentions it is having a harmful effect.

We must also examine whether a few cattle watering gashes are silting up the spawning beds in the first instance. Fifty years ago there were many more such watering places before the advent of the black polythene waterpipe and concerns about TB. Is it not far more likely that the cause is the shading out of light upstream, such that there is no riverweed ranunculus to bind the silts in place? Another issue is that of the lampreys, which stir up the spawning areas and make them appropriate for the fish. We are now told that they cannot get over the weirs. Fifty years ago they got over far higher weirs.

What about Coillte, private forestry owners and Bord na Móna in all of this? In the old days, the big rivers, a large proportion of the sources of which are in the midlands bogs, were drained and worked but no provision was made for the excess water. The bogs acted as sponges and provided a far more productive environment for salmonage young. The solution is simple. Each of the bog areas should be filled with a limited number of v-notch weirs. This would also alleviate flooding, which is a topical issue these days. The introduction of the European beaver in Scotland and Wales has been very successful. It would have a significant impact here. Also, special areas of conversation should be under the control of one agency. Under the current arrangement nothing can be done because each Department has regulations which block the other and they apparently take pleasure in doing so. It is a game to them.