Disentangling the cause of seabird deaths in South Africa

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(Reason Nyengera, 2 Mar 2017)

Net entanglements have become a major problem for seabirds in South African side trawl vessels. Despite huge success in reducing the incidental catch of seabirds in fishing nets, there’s been reports that an old type of vessel used in South Africa is still posing serious threats to seabirds.

The Albatross Task Force (ATF) has been highly successful in achieving a remarkable reduction in the incidental catch of seabirds in the South African hake trawl fishing industry through the introduction of bird-scaring lines; a simple and affordable solution. These lines act as visual deterrents to prevent cable strikes.

Despite these overwhelming achievements, there is a vessel class of side trawlers which is still posing a serious threat to seabirds. The side trawlers are some of the oldest vessels in South Africa’s demersal trawl fishery. These vessels haul catch over the side, rather than over the stern. The nets are also deployed over the side with the trawl warps passing through two blocks suspended at the stern. Hence trawl dragging is actively done from the stern.

Net entanglement is a major problem when the net stays loose on the sea surface for longer periods, for example during hauling and setting. Diving birds, mainly Cape Gannets can become trapped in the mesh of the net. Side trawlers are of special concern many because of the hauling process where loose net floats for a longer period compared to that of stern trawlers.

Evidence of this interaction by South African vessel, was captured on camera by our former Albatross Task Force leader Barry Watkins on one of his trips however we do yet have a clear idea of the magnitude of the issue in South Africa.

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