This dead humpback whale was seen floating miles off shore by several of the AU captains on Friday, May 28. The photos that captain Chuck and Matt took of the fluke (tail) allowed Sitka biologists to identify the whale as 952 or Aika (ah-ee-ka). The fluke of a humpback whale is unique to each individual, sort of like their fingerprint. There are catalogs of thousands of different photos of humpback flukes. These help researchers keep track of things like population size and return whales each season. Based on research conducted over the last thirty years, biologists in the area were very familiar with Aika. She has been a healthy mother and returning resident to Sitka waters since 1984.
Aika had died at least two days before our captains found her. Other boats had reported seeing her dead, but not yet expanded as much as she is here. It is extremely rare for a dead humpback to float. Commonly the area that is expanded in these photos (called ventral pleats) fills up with water. A large build up of gases in the stomach caused Aika to float for so long and get so large. It can be assumed that Aika died of natural causes as there is no sign of wounds or entanglement. A necropsy would be the only way to understand what killed her.
There isn’t any way to determine the age of Aika by sight alone. We know that she was at least 26, based on how many years she has been recorded in the area. It is difficult for biologists to age humpback whales, one method is by examining their earwax. Humpbacks, being a migratory species, travel to different parts of the oceans they live in. Varieties of minerals and temperatures in these different areas cause rings to form in the earwax, much like the rings on a tree. The AU boats will have to start bringing very large q-tips out on the water!
So little is known about humpback whales. Research on this endangered species began only about 35 years ago. We do know that the same whales we see feeding in SE Alaska swim 3,000 miles each winter to the Hawaiian islands where they mate and give birth, not eating the entire time. We also know that adult humpbacks grow to be 40ft in length, about the same size as a school bus. The calves are born roughly the size of a Ford Ranger and gain five pounds an hour drinking mom’s milk. The number of calves born each year increases by almost 7%, a promising statistic. Currently the estimated population of the north pacific humpback whale is around 20,000. As to why whales breach, or sing, or slap their tails is still a mystery.
The whereabouts of Aika’s body are unknown today. The current could have carried it off, or the stomach could have decompressed causing the carcass to sink. We are lucky to have the photos here, opportunities to see such a rare and magnificent sight don’t come around that often.