Festus, the humpback whale, was a regular visitor for forty-four years to the southeast Alaska coast. He was recognizable to humans by the black and white marking on his fluke. One day in 2016 he was found floating dead in Glacier Bay. Whale scientists determined that his cause of death was most likely starvation. A new paper by the Royal Society Open Science says that during an extreme heat event in the Northeast Pacific, when water temperatures rose 3-6℃ during 2014-16, an estimated 7,000 humpbacks disappeared during the period 2013-21. Populations had been increasing prior to that. The whales were removed from the Endangered Species list. Scientists think that the decline was a "mass mortality event" due to the lack of food. Phytoplankton, at the bottom of the marine food chain, cannot proliferate in warm water that has knock-on effects up to humpbacks despite their being flexible feeders. A similar high mortality event is affecting gray whales, which scientists think is due to the reduction in the size of a seabed crustacean that the whale consumes in the Bering Strait due to warmer ocean temperatures in the Arctic. [skinny whale on right; photo credit: UK Guardian]
Research in Antartica has shown that humpbacks breed less successfully when there is not enough food. It also results in 'skinny whales' that are more susceptible to disease. During the heat wave, fewer females showed up in the Au'au Channel between Maui and Lanai, a known breeding ground. Only three calves made the annual migration to Alaska, and they to went missing. To estimate the number of whales in the North Pacific, study authors used an extensive data base of identification information called "Happywhale" that is extremely accurate and can be described as a Facebook for whales since it uses similar algorithms for identifying individuals. One researcher told interviewers that, "Healthy oceans make healthy whales and vice versa.”