Over eleven years have passed since the last NATO sponsored meeting on Fishing which took the form of a Conference held in Trondheim in 1979. The proceedings contained in this book consist of papers presented in support of an Advanced Study Institute on Operations Research and Management in Fishing held at P6voa de Varzim, Portugal from March 25 to April 7 1990. It was originally intended to use the five themes, Production Functions and Management; Marine Fish Stocks; Fisheries Models; Fish Farming and Miscellaneous. There were contributions on Fish Processing and the Fish Farming papers were t original. It was also decided to group the papers on Fisheries Models and Marine Fish Stocks together which means the proceedings has four headings: - Opening Session - Production Functions and Management - Marine Fish Stocks and Fisheries Models - Miscellaneous The contributions give a broad and complete overview of historical approaches and of recent trends on research in different sectors of fisheries. Criteria for quota distribution and schemes based on conclusions drawn from models and methods are presented. Surveillance methods are described in relation to species conservation and catch improvement. Different levels of regulatory enforcement are discussed and the implications of new techlogies are introduced. Applications of Expert Systems to stock assessment and efficiency improvement in field sampling are presented. Models for fleet dispatch planning and fleet structure appraisal are introduced and procedures for operational capacity evaluation of fishery harbours are considered.