Genetic sampling of salmon in the River Shannon has begun as part of an international project to test the success of a fish-stocking programme on the River Rhine in Germany. The conservation scheme involves salmon ova, or eggs, being supplied to two German companies by the ESB and other Irish hatchery operators.
At Parteen Weir, 11 miles upstream from the Ardna crusha power station, a piece of tail fin from the male and female salmon is put in alcohol. A DNA sample is taken and catalogued. The fertilised eggs of these "parents" are then sent to Germany.
In four years, salmon which have returned to the Rhine to spawn will be examined to see what their ancestry is. This month, DNA samples were taken from 130 salmon by ESB staff on the Shannon and by the Marine Institute at Burrishoole, Co Mayo.
Mr Paddy Barry, hatchery manager at Parteen Weir, said the aim is to introduce as many Multi-Sea Winter (MSW) salmon as possible both in the Rhine and the Shannon. These winter in the sea for two or more seasons and return weighing more than 15lbs. In the glory days of the River Shannon, up to the 1940s, salmon weighing up to 60lbs were being caught.
"We feel we are making a big contribution because our fish are very big here. The Germans have overcome the first hurdle. Their next step is to see who is making the best contribution," Mr Barry said.
Proof of the German programme's success was evident last summer, when a 20lb fish was taken from the Rhine. Although the Irish would like to lay claim to it, its lineage cannot be proved. It will take eight years for a full scientific analysis of the programme to be available when the first fouryear cycle is completed.
Early in the new year, the orders for 300,000 fertilised eggs will be dispatched at a cost of £50 per 1,000. Staff have been "stripping" 800 salmon, and extracting the eggs and sperm for the breeding programmes. Fertilisation takes place externally.
Mr Gerry Gough, ESB fisheries manager, said the German orders do not interfere with the 10-year-old Parteen breeding programme. Between the natural spawning of wild salmon and the nursery project, the objective on the Shannon is to put 2,000 salmon up beyond the Parteen Weir. Last year, about 900 passed through the weir to spawn, considerably up from the 1980s when numbers were as low as 300.
"We have a 45 per cent success rate on that objective which was set two years ago," Mr Gough said.
The Parteen hatchery has about 3.6 million salmon eggs for breeding purposes, most of which will be placed in nursery streams on the Shannon system as "unfed fry", the first stage of the salmon's life after hatching. They will have a survival rate of about 0.1 per cent of returning from the sea to spawn.
About 150,000 are reared until they reach smolt stage, which occurs after 12 to 15 months, and they are tagged and released. A survival rate of between 2 and 3 per cent is normal after they spend a year or more in the seas around Greenland. However, they are not referred to as "wild".
It is an irony of history that Irish-bred salmon are swimming in the famous European river. In the 1920s, the Rhine supplied salmon for the restocking of the River Feale in Co Kerry.