Ana Hoff/Stockfood

Amid growing alarm on the part of environmentalists, wild-catch fishermen, and ocean scientists over vanishing fish stocks and pollution from offshore fish farms, here's a new idea: raising ocean fish, shellfish, and crustaceans in freshwater.

Several companies are showing that this can be not only environmentally smart but also a profitable addition to the $70 billion aquaculture industry. Pioneers include OceanBoy Farms, which raises Pacific white shrimp in central Florida; Australis Aquaculture, an Australian company that farms barramundi in western Massachusetts; and Virginia Cobia Farms, which produces tank-raised cobia.

Researchers at Florida's Harbor Branch Oceanographic Institute are working on ways to raise other high-value species such as pompano and black sea bass in closed freshwater or low-salinity systems. It isn't easy: many fish can tolerate only very specific salinity ranges, but anadromous fish such as barramundi spend part of their life cycles in fresh or brackish water, and some other species can be acclimated to changing salinities. If scientists succeed, we may come a small step closer to having our fish and eating it too.