Global yield looks to be maxed out.

• Position: Fish Farming - Brief article

Global fish production has reached an all-time high, according to research conducted by Nourishing the Planet for the Worldwatch Institute's Vital Signs publication. Aquaculture, or fish farming--once a minor contributor to total fish harvests--increased fiftyfold between the 1950s and 2008, and now contributes nearly half of all fish produced worldwide.

The United Nations Food and Agriculture Organization estimates that 53% of fisheries are considered fully exploited--harvested to their maximum sustainable levels--with no room for expansion in production. Population growth and a higher demand for dietary protein are putting increasing pressure on depleted stocks and threatened ecosystems. Mainstream approaches to fisheries management have focused narrowly on short-term profit and boosting production, Worldwatch maintains.

Increased farming of large predators, such as salmon and tuna, has led to overfishing of prey fish, including anchoveta and...