Steve Curwood speaks with marine mammologist Nina Young of the Center for Marine Conservation in Washington, D.C. about a recent wave of unexplained manatee deaths that has so far claimed 250 victims. With only 26,000 of the sea cows surviving today, marine conservationists are concerned by the loss of so many animals, many of which are adult females. Post-mortem necropsies are finding blood hemorrhages in the lungs, lesions, even muscular and neurological problems.