The claim was made at the annual convention of the Association of European Fish Producers in Kinsale, Co Cork where delegates called for an end to the practice.
If several species of fish get caught in nets and if a boat does not have a quota for a particular species under EU rules, the fish must be dumped back in the sea.
Sean O'Donoghue, who has been elected as the Association's first Irish President, says it is an appallingly wasteful practice when stocks are scarce.
He says the practice must be stopped.
He intends to form a united approach amongst all European fishermen to do so and pressure the EU Commission for change.
New types of nets or controlled arrangements to land all catches are amongst possible solutions.
The European Association of Fish Producers represents the owners of 10,000 boats.
