Maximum sustainable yield and species extinction in ecosystems

With intent to help fisherman catch the most fish in the long run and to protect fish populations from extinction, major world fisheries regulation agencies have passed recommendations to implement sustainability in fisheries through the application of “maximum sustainable yield” (MSY). We show that application of MSY policy will lead to extinction of a large number of fish species in most ecosystems. More precisely, we show: approaching MSY in ecosystems means that most likely fish species will be driven to extinction in every fishery that includes exploitation of at least one trophic level which is directly or indirectly used as food for a higher trophic level. Because such single and multispecies fisheries make up a great majority of existing fisheries, attempts to reach MSY should be discouraged instead of being legally prescribed as a goal. Based on our result, we offer a simple prescription for managing a fishery in agreement with the Convention on Biological Diversity.