Hundreds of tonnes of fish are being killed by illegal nets, according to fishermen's organisations on the south coast.
The fishermen claim the nets are being used by foreign boats and dumped to avoid detection.
But when that happens, they go on catching and killing fish beneath the surface which then decay and are useless.
The nets have small narrow mesh panels and may be used to catch small fish that are considered a delicacy abroad, but at a big cost to scarce stocks.
The South West Fishermen's Organisation says that its boats have recovered huge quantities of the nets around the Porcupine Bank and brought them ashore.
The EU has banned the nets, but there are reports from Brussels that the Commission is considering rescinding that ban under pressure from Spanish interests.
