Defenders of tilapia aquaculture point out that this young and rapidly growing industry has begun improving standards and toughening regulation. The two-year-old Aquaculture Stewardship Council, the brainchild of the conservation organization WWF and I.D.H., a Dutch sustainable trade program, is rolling out an inspection program for tilapia farms independent of the industry. Those that choose to participate — and pass — will receive labels identifying their product as “responsibly farmed.”

In a nod to its growing popularity, this year tilapia’s will be the first of 10 fish certification programs to be initiated. Aquafinca, which began adopting more environmentally friendly cultivation in 2006 to better appeal to large corporate customers like Costco, this year became the first farm to pass an initial inspection.

Proponents say tilapia aquaculture will only grow in importance because it provides food and jobs in a world of declining fish stocks and rising population. “There are going to be more farmed fish each year,” said Kevin Fitzsimmons, a biologist at the University of Arizona. “Think about it: if we tried to get beef from hunting, there would be a lot of hungry people.”

From Africa to the World

Native to lakes in Africa, this versatile warm-water fish was deployed by many governments in poor tropical countries around the world in the second half of the 20th century to control weeds and mosquitoes in lakes and rivers. In a cistern or pond, a few fish yielded dietary protein.

In retrospect, that global dispersal “maybe was not the best idea,” said Aaron McNevin, a WWF biologist who is coordinating the development of standards for tilapia farms, because tilapia “is one of the most invasive species known and very hard to get rid of once they are established.” Today, wild tilapia has squeezed out native species in lakes throughout the world with its aggressive breeding and feeding.

By the 1990s, businesses saw opportunity in farming this hearty species, which tolerates crowding and does not need expensive meat-based feed. Using selective breeding, scientists created today’s industrial strains: big, fleshy fish with tiny heads and tails, and intestines that allow them to absorb food faster. Farmed tilapia reaches its sales weight of about two pounds in roughly nine months of intensive feeding.