In the past 14 months, more than 400 dead dolphins have been found along the U.S. Gulf Coast, and scientists have now linked oil on eight of those dolphins to last year’s BP oil spill. While only a few hundred carcasses have been found, biologists say the number is likely much higher. According to a paper in the journal Conservation Letters, only one in 50 dolphins that die at sea are recovered on the Gulf’s shores. Also, about half of the recovered carcasses are newly born or stillborn infants, which some scientists say points to oil contamination. In fact, NOAA experts are bracing for the number of deaths to grow as the bottlenose calving season reaches full swing. Biologists contracted by the National Marine Fisheries Service to investigate the dolphin die-off have been ordered to keep their findings confidential, which has only increased interest in the matter.