Fishermen are being encouraged to take part in a new voluntary scheme to take litter they encounter while at sea back to port.

The initiative, "Fishing for Litter", is being promoted by the seafood development agency Bord Iascaigh Mhara.

24 trawlers based in the fishery ports of Clogherhead, Co Louth and Union Hall and Castletownbere in Co Cork are taking part.

BIM hopes to increase the number to 50.

The agency is providing fishing boats with large bags for collection of litter and also working with the port authorities to organise the removal of the material once it is landed.

Celtic Chieftain skipper Patrick Smyth told RTÉ News that his crew would find litter of some type every time they haul in their nets and all that is now bagged, whereas in the past it would have been thrown back into the sea.

BIM Chief Executive Tara McCarthy says the scheme is already working very well and two tonnes of man-made litter has been brought ashore at Clogherhead in Co Louth.

She said litter is generated at sea, or gets washed out from beaches and during floods and 80% of it is plastic.

It threatens sea life and marine habitats. Chemicals that get left in the sea may also have an effect.