Maximum Sustainable Yield

In economics, agriculture, and the study of ecosystems, the maximum sustainable yield (MSY) typically denotes the maximum amount of a resource that can be used or removed from a system without affecting the system's ability to maintain itself and replenish or [Page 1355]renew the resource at current levels in a sustainable manner. In economics, MSY refers to the theoretical equilibrium yield or the amount that may be harvested at a steady equilibrium state without significantly affecting the reproduction processes. It is calculated using the intrinsic growth rate of the resource stock and the environmental carrying capacity. MSY can be estimated from surplus production models such as the Gordon-Schaefer production function.

H. Scott Gordon argued in 1954 that economic rent from a common resource, such as open-access fishing waters, could not be captured by society. A common resource was prone to overharvesting because no one owner sets limits to maximize the long-term average yield. These concerns in the 1950s and 1960s led to changes in the international law of the sea and the development of exclusive economic zones.

Usually used in reference to fisheries or other aquaculture, MSY is the largest catch, long-term average yield, of fish or other resource that can be harvested under given ecological conditions without weakening the ecosystem's ability to maintain that level of species. For a situation where the population of the resource fluctuates over time, the amount of resource that can be harvested varies. MSY is also called maximum equilibrium catch, maximum sustained yield, sustainable catch, long-term potential catch, or potential yield.

The United Nations Convention on the Law of the Sea of 10 December 1982 referred to MSY in the conservation and management of stocks (Article 61 Conservation of the living resources, Section 3). The European Environment Agency recommends using MSY as a quality indicator for fisheries and aquaculture. MSY can also be used for evaluating strategies to rebuild a resource; for example, stocks can be rebuilt to a level that will produce at least MSY for prevailing environmental conditions. MSY can be confused with optimum sustainable yield (OSY), where OSY is the level of effort that maximizes the difference between total revenue and total cost. This level of effort maximizes the economic profit, or rent, of the resource being used. It usually corresponds to an effort level lower than that of MSY.

MSY as an indicator of the sustainable use of renewable resources has been important in the development of sustainable business practices, balancing economic and ecological factors. Beyond applications in fisheries and aquaculture, MSY is considered in sustainable business practices from the procurement of resources, to the production, use, and disposal of resources. Although MSY usually addresses one species within a system and a specific carrying capacity and does not incorporate economic or social values and balances, it is a useful concept to study common resources in terms of production costs and environmental carrying capacity.

Sustainable agriculture is the concept of plant and animal production practices considered in an integrated system according to the U.S. Food, Agriculture, Conservation, and Trade Act of 1990. Addressing the natural environment, economic health, and social equity, sustainable agriculture has a systems perspective, involves interdisciplinary research and education, and contends with stewardship of natural and human resources.

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