This paper estimates maximum sustainable yield and maximum economic yield from Schaefer and Fox surplus production bioeconomic models to find evidence of biological and economic overfishing, and their consequences in Gulf of Thailand demersal fisheries. The paper examines alternative policy instruments to reduce overfishing. The discussion emphasizes strengthening fishery management for implementing limited access, and a combination of co-management, and decentralization of fisheries management. The use of license fees that serves as a double dividend tax to reduce fishing effort and fund monitoring and enforcement has been proposed as one of the possible economic instruments.