Strait Science on NPRW
Jessica Crance, a bioacoustician at the Marine Mammal Laboratory at NOAA Fisheries Alaska Fisheries Science Center, gave the most recent Strait Science series talk on the North Pacific right whale.
There are three species of right whale: Southern right whale, North Atlantic right whale and North Pacific right whale. Crance’s talk focused on the North Pacific right whale, which has two major subgroups. The western population of the North Pacific right whale, found in Japanese and Russian waters, is estimated to be in the low hundreds. This population is genetically distinct from the eastern population, which is found in U.S. and Canadian waters. The eastern population, which feeds in the Bering Sea and in the Gulf of Alaska, is estimated to be in the low 30s.
With an estimated eight females — a recent study suggesting that the ratio of male to female right whales is 3:1 — learning about this population is critically important.
Right whales are best known for their white spots, called callosities. These are spots of dead skin covered with whale lice; it is these cyamids which are white. Interestingly, even these lice might be endangered. Since these patterns, like humpback flukes or human fingerprints, are unique, they are used to track and monitor the individual whales.
Crance went in depth talking about right whale calves because “we haven’t seen a calve in this population in a very long time,” she said. Such sightings are rare and would be important, because the last one was about 16 years ago. Mothers gestate for 12-13 months, and calves, which are 15 feet long at birth, nurse for about another year. Calves do not have callosities, because they do not have dead skin yet.
However, because they are so rare, habitat information, such as their calving grounds or migratory routes, is mostly unknown. The eastern population of the North Pacific right whale feeds in the southeast Bering Sea and the Gulf of Alaska around Kodiak. Sightings have been made in Hawaii and around Baja California, but there has only been one confirmed high-low latitude match, using the callosity patterns, which was in 1996.
In recent years, there were two pairs sighted in the Gulf of Alaska. Even more exciting, one in each pair was a new animal, unmatchable to others in a database of previous sightings. On August 21, one new right whale was seen with one right whale which matched one sighted on June 12 by Fisheries and Oceans Canada near Haida Gwaii. Three days later, on August 24, another new right whale was seen with a whale first seen in 2006 in the Barnabus Trough. As there have not been matches across the Aleutians, it is suspected that the right whales which feed in the Bering Sea and the right whales which feed in the Gulf of Alaska are different subgroups.
While difficult to obtain, biopsy samples can be taken from afar. A crossbow can be used to take a plug of skin and blubber, which can tell sex, reproductive status, and which stock the whale is from. Recent bi