The winter calving season for endangered North Atlantic right whales is nearly over—but researchers haven't seen a single newborn off the southeast U.S. coast, according to the Associated Press. This could be the first time in three decades that no right whale births have been recorded. “If we don’t get serious and figure this out, it very well could be the beginning of the end,” said Barb Zoodsma of the U.S. Southeast for the National Marine Fisheries Service. Right whales typically give birth to about 17 calfs a year. But in airborne surveys of the Georgia and Florida coasts, where female right whales migrate during the winter, trained spotters tasked with finding mother-and-calf pairs have yet to record any newborns this season. Their work reportedly wraps up on Friday. Scientists estimate that there are currently only 450 North Atlantic right whales remaining. This comes as 17 whales washed up dead on shores, and only five births were recorded in 2017. Necropsies on the dead whales found that at least four were struck by ships and at least two were caught in fishing gear.