A study has revealed that at least 160,000 and potentially in excess of 320,000 seabirds are killed annually in longline fisheries globally. Some previous studies have assessed the level of seabird by catching longline fisheries for particular regions and groups of seabirds, but this is the first study to provide a global estimate of by-catch of all seabirds in longline fisheries.
The most frequently caught birds were albatrosses, petrels and shearwaters, many of which are listed as threatened with extinction.
The study highlights that there is evidence of substantial reductions in by-catch rates in some key fisheries. These reductions were due to a number of factors, including greater and more effective use of mitigation measures specifically designed to reduce seabird by-catch, such as bird scaring lines, also known as tori lines.
This has certainly been the case in South Georgia and the Falkland Islands, where seabird by-catch levels associated with longline fisheries have been reduced to negligible levels.
In the case of South Georgia, seabird by-catch in the longline fishery for Patagonian toothfish was reduced from several thousand birds in the mid 1990s to the current annual estimate of zero birds in a very short period of time.
Similarly, seabird by-catch in the longline fishery for Patagonian toothfish in the Falkland Islands has also been substantially reduced, with zero by-catch recorded for the last three years.
In both cases, the reduction in seabird by-catch has been achieved through the introduction of mandatory mitigation measures, the effective implementation by vessels of these measures, supported by observer programmes to monitor the efficacy of measures and by-catch rates.
Dr Paul Brickle of the Falklands’ Fisheries Department reported that “the fishing industry has made great efforts in addressing the issue of by-catch by implementing seabird friendly practices and good house keeping on their long-liners operating in the Falkland Islands.”
The reduction of seabird by-catch in these, and other fisheries, demonstrates that the problem of seabird by-catch in long-line fisheries can be reduced to negligible proportions using relatively simple, but effective, measures.
Unfortunately, the study reports that there remain many longline fisheries which have very high levels of seabird by-catch mortality and others with insufficient data to properly assess seabird by-catch. Some of these fisheries are known to impact seabirds breeding on the UK South Atlantic Overseas Territories of the Falkland Islands, South Georgia and Tristan da Cunha, which collectively support a third of the world’s breeding albatrosses.
It is important that efforts continue in the Falkland Islands and South Georgia to minimise seabird mortality in longline fisheries, as well as in trawl fisheries, and that the assessment of seabird by-catch in other relevant fisheries is improved, and effective mitigation measures introduced and implemented to reduce levels of by-catch.
The study does not consider by-catch of seabirds in trawl and gill-net fisheries, which are now recognised as contributing significantly to the global by-catch total in certain regions.
Commenting on the report, Dr Martin Collins of South Georgia Government indicated that “the success of the South Georgia and the Falklands longline fisheries in virtually eliminating seabird by-catch, demonstrates what can be achieved with careful mitigation measures.
“There is now an urgent need for similar mitigation measures to be introduced to fisheries in other areas to halt the alarming declines in many populations of albatrosses and petrels”.
The study referred to in the article was conducted by the (RSPB) and BirdLife International.