Mincing and mealing: a test of offal management strategies to reduce interactions between seabirds and trawl vessels Edward Abraham Dragonfly, 10 Milne Terrace, Island Bay, Wellington (
[email protected]) Advisory Group: John Cleal F. V. Management Services, P.O. Box 1279, Nelson, New Zealand David Middleton New Zealand Seafood Industry Council, Private Bag 24-901, Wellington, New Zealand Johanna Pierre Department of Conservation, PO Box 10-420, Wellington 6043, New Zealand Nathan Walker WWF-New Zealand, PO Box 6237, Wellington 6003, New Zealand (present address: Ministry of Fisheries, PO Box 1020, Wellington 6001, New Zealand) Susan Waugh Ministry of Fisheries, PO Box 1020, Wellington 6001, New Zealand Report prepared for the Department of Conservation, 7 May 2007 (Update 7 April, 2008). 1 1. Summary Recent work aimed at reducing the capture of seabirds on trawl warps has shown that warp strikes are associated with the discharge of waste while fishing. Offal management is therefore a key measure for reducing this incidental catch. An experiment to test the effect of two offal management strategies on the numbers of seabirds attending a fishing trawler was carried out during September - October, 2006. The two treatments were (1) sending all offal and waste to the meal plant, so that discharge was reduced to sump water, and (2) passing all waste through a mincer, with 25mm holes in the mincing plate, before discharging it. The two treatments were compared with a control, where all waste was directly discharged. To determine the response to the treatments, bird numbers were counted in a semicircular sweep of 40m radius, centered on the middle of the stern of the vessel and extending behind it.