1. National Veterinary Institute, PB 8156 Dep., N-0033 Oslo, Norway, AgResearch Ltd., Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand, Chemistry Department, The University of Waikato, Private Bag 3105, Hamilton, New Zealand, Chemistry Department, University of Oslo, P.O. Box 1033, N-0315, Oslo, Norway, Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada, Flødevigen Research Station, Institute of Marine Research, Flødevigen,...