This article reviews economic concepts for the management of two related renewable resources, fish stocks and water. The authors discuss scarcity and the economics of optimal use that also addresses external costs and benefits and market failure arising from incomplete or weak property rights, issues in optimal use over time, and growing importance of public benefits. Also discussed are the economic approaches proposed to resolve the scarcity and market failure challenge in water and fisheries that are similar despite key differences, which include the importance of economic incentives, getting prices right so that the price of fish or water reflects its economic opportunity cost, including the value of the resource in the environment and over time, the challenge of managing a resource that is highly variable and stochastic, and adequately adapting economic frameworks to existing institutional constraints and limitations. Finally, emerging issues are discussed, including greater importance of public benefits arising from ecosystem and biodiversity considerations, climate change, and allocation of a scarce resource among competing uses and users.