Back in the lab, biologists get a snapshot of the orcas' health using hormonal information extracted from the samples. Unfortunately, the hormones and other data paint a grim picture. Southern resident orcas, which spend May to October in the Salish Sea, are "doing really bad right now," Wasser says.
There are only about 79 resident killer whales left, legally protected as an endangered species in the U.S. In the 1960s, there were nearly 150 resident orcas living in the waterway between Canada and Washington. But, based on a critical miscalculation by the captive orca industry -- which had assumed the whales numbered in the thousands, not hundreds -- 48 resident whales were harvested by the mid-1970s.
Forty years later, the orca population has not recovered. The whales' health is closely tied to the health of Chinook salmon in the Pacific -- resident orcas are picky eaters, subsisting on these salmon for nearly 70 percent of their diet. When the Chinook salmon population dips, orcas go hungry. Based on hormones in the orca scat (found by Tucker), Wasser and his colleagues can tell how well the whales are eating.