During 5-7 September 1990, the Scientific Council held a Special Session on "Management Under Uncertainties Related to Biology and Assessments, with Case Studies on Some North Atlantic Fisheries" at the Lord Nelson Hotel, Halifax, Nova Scotia, Canada, with J. Shepherd (EEC-UK) as convener. Keen interest in the contributions and associated discussions prompted the Scientific Council to consider publishing all contributions in a single volume of NAFO Scientific Council Studies. Of the 22 presentations made at the Session, 16 papers and 5 extended abstracts were accepted for publication in this issue of Studies after review by the convener and the editor. The contributions are printed in the order they were presented at the Session.

At the Annual Meeting of the Scientific Council of NAFO in September 1980, it was agreed that a review of environmental conditions in the northwest Atlantic during the 1970-79 decade was desirable. Consequently, a symposium was held at the Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada, on 15-16 September 1981, during which 15 contributions were discussed (NAFO Scientific Council Reports for 1981). Several of the papers were solicited by the convener to ensure that the major aspects of environmental conditions were covered. Twelve of the contributions are included in this volume.