Biomass of Antarctic Krill in the Scotia Sea in January/February 2000 and Its Use in Revising an Estimate of Precautionary Yield
ARTICLE IN PRESS Deep-Sea Research II 51 (2004) 1215–1236 www.elsevier.com/locate/dsr2 Biomass of Antarctic krill in the Scotia Sea in January/February 2000 and its use in revising an estimate of precautionary yield Roger P. Hewitta,Ã, Jon Watkinsb, Mikio Naganobuc, Viacheslav Sushind, Andrew S. Brierleyb,1, David Demera, Svetlana Kasatkinad, Yoshimi Takaoe, Cathy Gossb, Alexander Malyshkod, Mark Brandonf, So Kawaguchic, Volker Siegelg, Philip Trathanb, Jennifer Emerya, Inigo Eversonb, Denzil Millerh aSouthwest Fisheries Science Center, 8604 La Jolla Shores Drive, La Jolla, CA 92037, USA bBritish Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3 0ET, UK cNational Research Institute of Far Seas Fisheries, Orido 5-7-1, Shimizu, Shizuoka 424, Japan dAtlantNIRO, 5 Dimitry Donskoy Street, Kaliningrad 236000, Russia eNational Research Institute of Fisheries Engineering, Ebidai Hasaki, Kashima-gun, Ibaraki 314-0421, Japan fEarth Sciences, The Open University, Milton Keynes MK7-6AA, UK gInstitut fu¨r Seefischerei, Palmaille 9, D-22767 Hamburg, Germany hMarine and Coastal Management, Private Bag X2, Roggebaai 8012, South Africa Accepted 18 June 2004 Available online 23 September 2004 Abstract In January and February 2000, a collaborative survey designed to assess the biomass of Antarctic krill across the Scotia Sea was conducted aboard research vessels from Japan, Russia, the UK and the USA using active acoustic and net sampling. Survey design, sampling protocols, and data analysis procedures are described. Mean krill density across the survey area was estimated to be 21.4 g mÀ2, and total biomass was estimated to be 44.3 million tonnes (CV 11.4%). This biomass estimate leads to a revised estimate of precautionary yield for krill in the Scotia Sea of 4 million tonnes.
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