As doctors and health specialists urge us to eat more fish, environmentalists are warning that we may end up harvesting our favorite sea life to the brink and beyond. Some of the most popular varieties have already begun to decline precipitously, experts say. And that's with Americans eating less than half of what the U.S. government's dietary guidelines suggest. While fish farming might seem to offer the perfect solution to the overharvesting problem, in its current state, it's deeply flawed from a sustainability standpoint, says Theresa Sinicrope Talley, a coastal specialist with the California Sea Grant Extension Program at Scripps Institution of Oceanography at UC San Diego. That's due to the food most fish farmers are feeding their stock: other fish.