Nairobi — Illegal fishing by factory ships is costing African countries over $1 billion a year as the threat to fish stocks reaches crisis level.

At an international environment conference in London last Thursday, Britain's International Development Minister Gareth Thomas said if action is not taken immediately, illegal fishing could have a devastating impact on fish stocks off the coast of Africa.

Experts say unless much tighter regulation and policing are introduced, over-fishing will also lead to the demise of African countries' own local, small-scale fishing industry.

Tens of thousands of fishermen and women depend on small-scale fishing for their livelihood.

The continent's vast reserves of fish stocks are rapidly dwindling due to industrial fishing boats catching massive quantities of fish for export.

They end up keeping around a quarter of the catch -- throwing the rest back dead. Many then sell the catch illegally.

Experts say the problem costs African countries over $1 billion a year, and devastates local economies which rely on fishing.

The total cost to the world economy of illegal fishing and poor management of marine stocks is an estimated $100 billion every year.

Speaking at an Environmental Justice Foundation event in London, Mr Thomas said if illegal fishing continues at its current rate, stocks will be devastated within years.

Apart from the disastrous environmental impact, millions of people will not have a way to make a living, he said.

Illegal fishing undermines food supply chains, deprives fishing communities of sustainable livelihoods, and steals a vital source of income from developing nations, the conference heard.

Mr Thomas referred to the new Partnership for African Fisheries programme that Britain's Department for International Development is funding through the African Union and the New Partnership for Africa's Development.

The £7m programme will address both illegal fishing and management of fisheries.