The amount of edible fish being discarded overboard can be virtually eliminated by making fishermen count all their catch towards their quota, a trial has shown.

The UK trial reduced discards of North Sea cod and Western Channel sole to just 0.2%, compared to average discard rates for North Sea cod trawlers of around 38%, and 28% for Western Channel sole beam trawlers in 2010.

Participating fishermen also drastically reduced the amount of undersized fish they caught, showing that selective measures such as using larger net meshes to avoid juvenile fish – which would otherwise count in the quota – were effective.

Under current rules which govern fishing across European Union countries, fishermen have quotas for certain fish, but can carry on fishing once the limits are reached as long as they do not bring any more of that species to shore.

As a result, tonnes of edible fish which exceed the quota are thrown back to sea as "discards", accounting for up to 90% of the total catch in some fisheries.

Wasting usable fish in this way is a major issue, as three quarters of EU fish stocks are overfished.

In trials of the "catch quota" scheme in the UK, English fishermen catching West Channel sole and North Sea cod have to bring to land all of the fish of those species they catch, so they all count as part of their quota.

While they have a larger quota than they would otherwise, once they have used it up, they have to stop fishing completely.

Onboard monitoring including the use of CCTV cameras has been used to check whether fishermen are following the rules.

Fisheries Minister Richard Benyon said the results of the trial were "tremendous", adding he was pleased that more fishermen had joined the 2012 catch quota scheme. He said: "Discards are a product of the broken Common Fisheries Policy and I will continue to press the EU until we eliminate this wasteful practice."