Feminized cod on the high seas

From Baltimore, at a meeting of the Society of Environmental Toxicology and Chemistry

Male cod in the open ocean are producing vitellogenin, an egg-yolk protein ordinarily made only by females.

Vitellogenin “is a highly specific indicator of a fish’s exposure to estrogens”—female sex hormones—as well as to pollutants that mimic them, notes Alexander P. Scott of the Centre for Environment, Fisheries and Aquaculture Science in Weymouth, England.