From fishing to the sustainable farming of carnivorous marine finfish

Carnivorous marine finfish aquaculture has been the subject of intense criticism. Because the process consumes more fish biomass in the form of fishmeal and fish oil than it produces, critics argue carnivorous marine finfish aquaculture causes a net loss of living marine resources and is unsustainable given the continued expansion of the industry. While this "fish-in fish-out" critique is factually correct, it fails to capture all the costs and benefits of carnivorous marine finfish aquaculture. Accepted theories on energy and matter flow between trophic levels indicate that carnivorous marine finfish aquaculture appropriates less ocean primary production than commercial fishing and, as we show, it is generally less demanding of agricultural resources and inputs than terrestrial animal husbandry. The basic fish-in fish-out critique also neglects to consider the fishmeal industry with sufficient granularity. The amount of small pelagic fish harvested for reduction has remained stable despite increased carnivorous marine finfish production, largely due to research into alternative ingredients that has decreased fishmeal and fish oil inclusion rates and caused aggregate fishmeal and fish oil consumption by the aquaculture industry to plateau in recent years. Consideration of all the costs and benefits of carnivorous marine finfish aquaculture suggests that the industry is progressing toward sustainability.