Fewer than three out of every 100 wild salmon that migrate to sea from the River Bush are returning to spawn in the waters where they hatched.
That is the low survival rate recorded in the most recent results from the Bushmills salmon station, which is monitoring the endangered fish.
Statistics published by the Department of Culture, Arts and Leisure, which oversees the angling estate, revealed that only 926 (2.7%) of salmon that migrated to sea in 2012 returned to spawn. In 2011 the figure was even lower, at 649 (2.6%).
These are the two lowest levels of salmon returns since the station started recording survival rates in 1987.
Meanwhile, in four out of six salmon rivers monitored across Northern Ireland, salmon weren't laying enough eggs to seed the available nursery habitat, meaning they were below their conservation limits. These rivers are the Bush, Blackwater, Glendun and Shimna.
However, the Maine River exceeded its conservation target, as did the Clady River.
The DCAL report revealed that only 20 salmon were caught commercially in the area it covers – all of them netted in Lough Neagh – a fall from 1,146 in 2011. "This was due to the voluntary action of fishermen in response to a call made by DCAL to not fish for salmon in the DCAL jurisdiction," a spokesman said.
Northern Ireland Freshwater Taskforce says we remain unlikely to meet the first of our European freshwater targets in 2016.
Senior conservation officer John Martin said: "The Northern Ireland Executive hasn't put any additional funding arrangements in place to ensure that we will achieve good ecological status of our freshwater rivers by 2016."
At the moment only 28% of rivers in Northern Ireland are classed as being of good ecological status, he said.
Mr Martin added: "If Northern Ireland doesn't meet those targets we will have to come up with reasons why not. If the European Commission is not satisfied with those reasons, we could face infraction fines."
Mr Martin said the biggest source of pollution in freshwater habitats is diffuse pollution, a high percentage of which comes from agricultural run-off.
The Atlantic salmon is renowned for its vast migrations across the North Atlantic and its ability to leap over obstacles as it makes its way upstream when it returns to the river of its birth. In its North Atlantic range the species is now extinct or in critical condition in about one-third of rivers and is endangered or vulnerable in a further third.