Hundreds of thousands of seabirds are being killed every year by long lines set to catch fish, despite efforts to tackle the problem, researchers warned yesterday.
Birds such as albatrosses, shearwaters and fulmars are being accidentally caught by hooks on the lines which can be more than 60 miles long, and dragged underwater where they drown.
A study by the RSPB and BirdLife International, published in the journal Endangered Species Research to mark World Oceans Day, warned that at least 160,000 and potentially more than 320,000 birds are killed each year in this way.
The conservation groups said some species of albatross and other seabirds were dying at rates which were driving them towards extinction.
According to the research, there was evidence of substantial reductions in the number of birds accidentally ensnared as “bycatch” in the longlines in some fisheries.
But the assessment showed other fisheries where data has not been available or the scale of the problem has not been fully documented, adding to the estimated global tally.
These included the Spanish longline fleet in the Gran Sol grounds off south west Ireland, where the researchers estimated more than 50,000 birds, mostly shearwaters and fulmars, were being killed each year.
And the Japanese tuna fleet was causing the death of more than 20,000 birds, mostly albatrosses, the study suggested.
While the full extent of the impact of fisheries on seabirds remains unknown, because of continuing gaps in the data, the conservation groups said the declines in many species were a cause for grave concern.
Some 17 out of the 22 albatross species are threatened with extinction, they warned.
Orea Anderson, policy officer for the Global Seabird Programme and lead author of the study, said: “It is little wonder that so many of the affected seabird species are threatened with extinction – their slow rate of reproduction is simply incapable of compensating for losses on the scale this study has demonstrated.”
The conservationists said that when regulations are enforced in fisheries, substantial reductions in seabird “bycatch” can be achieved.
Seabird deaths around South Georgia have dropped by 99 per cent as a result of regulations, while South Africa achieved a drop of 85 per cent in seabird bycatch in its foreign-licensed fleet.
The RSPB and BirdLife International said simple cost-effective measures could cut the number of birds affected.
Cleo Small, senior policy officer for the Global Seabird Programme and co-author of the review, said: “Using simple bird-scaring lines and weighting of hooks as they enter the water could dramatically reduce the number of seabirds being killed.”