1. Department of Fisheries and Oceans, Winnipeg, Manitoba R3T 2N6, Canada, Departments of Chemistry and Zoology, University of Manitoba, Winnipeg, Manitoba R3T 2N6, Canada, Food Research Division, Health Canada, Ottawa, Ontario K1A 0L2, Canada, and Department of Chemistry, University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada