There has been a common understanding among marine scientists and conservationists that longline fisheries are the main cause of seabird population declines. This has stemmed from the knowledge that fishing lines, after being deployed, fail to sink straight away therefore allowing seabirds to dive down and attempt to eat the baited hooks. Instead of a successful feed however, seabirds tend to get stuck on the hook and drown as the line sinks.
Some fishing fleets have drastically reduced seabird mortalities through the use of methods such as weighted hooks which allow the line to sink faster after entry into the water and also through the use of bird – scaring lines. However, other fishing fleets have failed to monitor the decline in seabirds or have poorly implemented steps that could reduce the problem to negligible proportions.
Researchers from the RSPB and Birdlife International suggest that much of the data on seabird populations and the fishing impacts on them are poor, particularly in areas such as Iceland, the Faroe Islands, Norway, distant Asian fishing grounds and the Mediterranean. They have estimated that bird deaths range from 160,000 – 320,000 with the Spanish longline fleet killing around 50,000 birds a year (mostly shear waters and fulmars) and the Japanese tuna fleet killing an estimated 20,000 seabirds a year.
Orea Anderson, policy officer and lead author of the study on fishing impacts and associated seabird decline, says “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 .”
With seabird populations facing an uphill struggle for recovery it is now up to countries worldwide to step up and implement effective measures to protect them, none more so than the UK. The UK overseas territories in the South Atlantic hold a third of the world’s breeding albatrosses. As a result, the UK holds a major responsibility to ensure fisheries in these territories employ methods to reduce seabird mortalities. Pressure is also being placed on the EU to deliver a robust set of remedial measures after the forthcoming EU plan of action for seabirds.
Some successes have already been achieved in reducing seabird declines. Tough measures around South Georgia in the South Atlantic have brought about a 99% reduction in seabird mortality with South Africa achieving an 85% drop in its foreign licensed fleet in 2008. Recent developments in April of this year saw Brazil pass a law requiring stringent by-catch measures in its domestic tuna fleets.
The Albatross Task Force (set up by Birdlife International and the RSPB) are discussing further mitigation measures including; dying fish bait blue to make it less visible to birds, setting lines at night when birds are less active, setting lines deeper underwater through the use of chutes and controlling the discards of unwanted fish. It is indisputable that the further implementation of stringent measures is required in order to stop the irreversible loss of seabird species.
By Anthony Kubale