By Martin Cassidy
BBC Northern Ireland rural affairs correspondent
One in four Irish Sea cod are being caught illegally, an international conservation body has said.
The International Council for the Exploration of the Sea (ICES) claimed that unrecorded catches by fishermen were undermining the European quota system.
Fishermen in County Down fishing ports disputed the ICES figures
The marine scientists said their most plausible forecast for Irish Sea cod catches assumed a catch in 2005 that was 25% greater than the total allowable tonnage.
But fishermen in County Down fishing ports dispute the ICES figures on unreported landings.
'Always a risk'
The problem of unrecorded catches has been recognised by the European Fisheries Commissioner, Jose Borg, who condemned the practice while on a visit to Kilkeel harbour.
"It is a fact that we need to be aware that the control measures need to be properly implemented," he said.
Commissioner Borg said there was "always a risk" for any fishery that "once the quota is exhausted, the fishermen continue fishing and catch beyond that quota".
In its report, which has been forwarded to Commissioner Borg, ICES said it believed Irish Sea fishermen were failing to disclose the true extent of their catches.
The marine scientists also suggested that what happened this year in the Irish Sea was not unique, revealing a pattern of under-reporting which had undermined the quota system and the fish conservation measures based upon it.
ICES said a vicious cycle had developed in under-reporting of landings by local trawlers, forcing scientists to factor in estimates of the extent of misreporting by fishermen in an effort to calculate the Irish Sea cod stock.
The marine organisation said the situation had now deteriorated to a point where the quota system could no longer be relied upon to restrict fishing.
Ironically, the under-reporting of catches may be working against fishermen.
According to ICES, lower catches immediately increased fears of stock collapses and led to scientists calling for even deeper cuts in allowable catches.
Fishermen's leaders though have been quick to discount the ICES claim of significant under-reporting of catches.
The Irish Sea fleet faces a 15% reduction in the cod quota
Dick James of the Northern Ireland Fish Producers' Organisation said that cod represented the only species where there may be a problem.
"People try and make out it is a serious problem, (but) it isn't. It's confined to one species in the Irish Sea and the levels of misreporting on it are nothing like what people imagine," he said.
However, ICES made it clear that under-reporting of catches was not a recent phenomenon and said that over time, it had become impossible to establish the real stock situation.
The scientists said they had concluded that in such situations, it was better to change route and focus on restricting the number of days fishing boats may go to sea.
The European Commission has responded by proposing to reduce the white fish fleet to 102 days at sea next year (18 fewer than in 2005), while the prawn fleet will see its fishing window reduced from 252 to 214 days.
Despite the problem with under-reporting of catches, the commission is still issuing quotas for next year.
In the case of cod, the Irish Sea fleet faces a 15% reduction while the prawn quota has been reduced by more than 10%, not because the stock is under pressure, but simply that cod is often a by-catch as trawlers scour the muddy bottom of the Irish Sea.
As usual, the proposals will form the basis for the annual wrangle which is the December fisheries council in Brussels.
Conservationists and fishermen can expect the outcome of that just before Christmas.
The European Commission said it hoped to open a new fisheries control agency based at Vigo in Spain next year to co-ordinate the strengthening of controls throughout European waters.