In lamenting the state of the world’s oceans, Alan Sielen (“The Devolution of the Seas,” November/December 2013) cites a 2003 study conducted by the marine biologists Ransom Myers and Boris Worm, who concluded that the number of “large fish,” such as tuna and swordfish, had declined by 90 percent since 1950. Although Sielen admits that the study “provoked controversy among some scientists and fishery managers,” he downplays such criticism.

Myers and Worm’s results were skewed because most of their data came from longline tuna fisheries, which exclusively target larger fish. A number of peer-reviewed studies have since argued that these findings are inaccurate. Recent data suggest that the world’s tuna population has decreased by only around 60 percent since 1950, and the Marine Stewardship Council declared the U.S. North Atlantic swordfish sustainable in 2013.

Executive Director, Saving Seafood