Ozone layer depletion may be contributing to the decline of cod stocks in New England, according to a study published in the Journal of Experimental Biology. Using lab experiments, researchers at the University of New Hampshire found that ultraviolet radiation penetrating the atmosphere could be fatal or debilitating to cod embryos and larvae, which live close to the ocean surface. The greatest threat to juvenile cod are predators, which snap up 99 percent of the juveniles before they can reproduce. But the researchers cautioned that conservation efforts to restore the greatly overfished cod stocks may fail unless they take into account the problems of ultraviolet radiation.