Effects of Fish Extinction on Ecosystems

Nutrients such as nitrogen (N) and phosphorus (P) are critical for supporting the productivity of plants and microorganisms at the base of aquatic food webs. Fish play an important role in nutrient cycles because they store a large proportion of ecosystem nutrients in their tissues, transport nutrients farther than other aquatic animals and excrete nutrients in dissolved forms that are readily available to primary producers. Although the influence of fish communities on food web structures, nutrient recycling, and productivity is well documented, little is known about the effects on the ecosystem of a reduction in the fish species richness. It is therefore of significant importance to evaluate the potential impacts of ongoing decreases in fish diversity.