The Irish government has been criticised for allowing more salmon to be caught at sea than its advisers recommended.
A salmon leaping at a weir in the Republic of Ireland
Conservationists and anglers are angry that the government has gone against advice from its scientific experts.
The minister responsible argued that he had to balance maintaining the stocks with the needs of fishing communities.
The annual quota of salmon to be caught by drift nets offshore has been set at 140,000 - 40,000 more than recommended.
"In 1970, the number of salmon reaching our shores was, according to scientists, in excess of one million," said Vincent Duigan of the STOP Driftnets Now Campaign.
"That number had decreased by 2004 to a total of 345,000.
"This decision by the minister is an absolute disaster. It does not hold out any hope for recovery of the salmon stock."
While the government promised to abide by scientific advice, the minister said the scientists changed the basis of their calculations at the 11th hour this year. So their recommendations were not followed.
"I have a very difficult job," Irish Marine Minister Pat the Cope Gallagher said.
"It's a balancing act between the commercial sector and the tourism and angling sectors. We must, of course, protect and conserve our salmon stocks. But, at the same time, we can exploit those stocks on a sustainable basis."
Salmon trying to swim up Ireland's rivers face even more obstacles
The Irish government's decision has also prompted international criticism. Fish caught off the Republic's coasts are destined for rivers across Europe.
So the decision to allow more drift-netting has wider implications.
Mr Gallagher said that growing calls for a complete buy-out of Irish drift-nets should come with money to provide compensation.
"The simple answer, but I don't know if it is a realistic one, is to stop drift-netting," he said.
"But it doesn't necessarily follow that it is the right thing to do. If other countries are of this view, then perhaps these other countries might well be interested in making funding available for a buy-out."
Widespread illegal fishing and poaching provides further unknown pressures on fish stocks off the Republic's coasts, some destined for rivers in Northern Ireland.
Whichever advice is heeded, salmon trying to swim up Ireland's rivers face greater obstacles than ever before.