For the past five years, the number of Gray Whales migrating from Alaska to the Pacific shores of Mexico has decreased by nearly 25 percent, from 27,000 to about 20,500. Many that are seen appear malnourished and more numbers than usual have ended up dead along the shore. Most research points to climate change and they have been protected since 1972 with the Marine Mammal Protection Act. Trouble for them could lead to bigger problems. “They’re sentinels for what’s going on in the North Pacific ecosystem,” says Sue Moore, a research scientist at the University of Washington. The investigation continues. Stay tuned.