By Richard Black
Environment correspondent, BBC News website
The government is to call for a Europe-wide system for tracking fish to help cut down on illegal fishing.
Patagonian Toothfish stocks are being decimated by illegal fishing
Fisheries Minister Ben Bradshaw and Overseas Development Minister Gareth Thomas say it will make it harder for illegal catches to enter the EU.
The plan, including electronic records of vessels and catches, will be backed by supermarkets and environmental groups at a meeting on Monday.
The ministers will also pledge £15m to help Sierra Leone stop illegal fishing.
Environment groups say the trade deprives poor countries of $9bn (£4.5bn) per year, of which about $1bn relates to African countries.
The tracking system would help regulate fishing by allowing fish to be traced "from the moment they are caught to when they are served on a customer's plate" - says the Department for Environment, Food and Rural Affairs (Defra).
This would include keeping electronic records of vessels, skippers and fishing grounds, including details of catches, time at sea and onward shipping and of delivery to buyers.
"More than 50% of the world's fish stocks are exploited to their limits and more than 25% are depleted," Mr Bradshaw told the BBC News website, "and illegal, unreported and unregulated (IUU) fishing is a major contributor.
"The main victims are poor countries which don't have the capacity to manage their fisheries."
He and Mr Thomas will tell the London meeting that combating IUU fishing will boost those countries' incomes as well as conserving fish stocks.
Last year a major scientific report concluded there would be no sea fisheries left within 50 years if current trends continued; and IUU fishing is the principal factor behind the decline of some species.
A number of systems now exist to monitor, track and certify fish, and the European Union is discussing proposals that could implement such schemes across the region.
A recent study said there would be no viable sea fisheries in 50 years
Also on the table are stronger laws to punish transgressors, modelled on the US Lacey Act, which makes it illegal for any US citizen to engage in any aspect of trade in illegally caught fish. Jail terms of several years have resulted from prosecutions under the act.
Following a recent meeting between fisheries ministers and the European Commission, a commission spokesman said there was "overwhelming support" for such measures within the EU.
Within Britain there is also support from within the industry, with Cliff Morrison, chairman of the seafood group within the UK Food and Drink Federation (FDF), saying: "The issue of IUU fishing is at the forefront of the food processing industry's agenda.
"The development and implementation of the industry's code of practice to counteract IUU fishing activities is a major step in addressing this problem."
The government believes the FDF's code of practice is a model which the EU could adopt.
The Viana, from Uruguay, was controversially cleared two years ago of illegal fishing near Australia
Away from Europe, the government and some environment groups are looking for ways to rein in fishing boats operating under flags of convenience.
The 2005 report Closing the Net, commissioned by the High Seas Task Force, found that more than 17% of the world's fishing vessels operating in open waters are either registered under flags of convenience or not registered at all.
There are virtually no controls on how these vessels operate.
The report noted that about 1,000 ships appeared to have no authorisation to fish anywhere, yet brought back catches, and asked rhetorically: "Where were they fishing?"
Mr Bradshaw said: "The EU has responsibility, as do a number of countries including Japan, South Korea and Taiwan, to get a greater measure of control on flags of convenience."
The European Commission is aiming to publish its proposals on IUU fishing later this year.