BirdLife International's Albatross Task Force is comparing 5-kg steel weights with the standard concrete weights used by the demersal longline fishery in Namibia. The FV Joao N Castro sailed a few days ago from Walvis Bay with John Paterson of the Namibian section of the task force aboard to conduct the experimental work.
Loading steel weights onto the FV Joao N Castro in Walvis Bay, Namibia
Photograph courtesy of the Albatross Task Force
"The problem with concrete weights is that they get damaged quickly and loose mass, resulting in slow-sinking gear. Effective line weighting is the most important factor of best practice mitigation for demersal longline fishing... . By making a direct comparison with standard gear, we will be able to measure the sink rate [and] identify the level of seabird bycatch and fish catch associated with different weighting configurations."
Namibian waters fall within the nutrient-rich Benguela Upwelling System that supports large populatios of albatrosses, petrels and shearwaters of a number of species.
Spectacled Petrels occur in Namibian waters where they are risk to longlines
Photograph by Ross Wanless
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With thanks to Oli Yates.
John Cooper, ACAP Information Officer, 25 June 2012