UPDATE, JAN 16, 2016
The orca calf found dead on the west coast of Vancouver Island
has been identified as a transient orca from the Gulf of Alaska
population. The finding was based on DNA analysis. The cause of
death has not yet been determined. For additional information,
news release from Vancouver Aquarium.
For the fourth year in a row, federal biologists have attached a satellite tag to one of Puget Sound’s killer whales to track the orcas as they move up and down the West Coast.
On New Year’s Eve, researchers with NOAA’s Northwest Fisheries Science Center used a dart to afix the tag to the dorsal fin of K-33, a 15-year-old male named Tika. He is the son of 29-year-old K-22, or Sekiu. As of this morning, the tagged whale (and presumably his pod) was at the junction where the Strait of Juan de Fuca enters the Pacific Ocean.
Data from the tagging project could be used to expand the designated “critical habitat” for the endangered orcas to areas outside of Puget Sound. I’ll explain more about the tagging project in a moment, but first an update on the death of a newborn killer whale.
Deceased orca calf
If you haven’t heard, a young killer whale was found dead on Dec. 23 on the west coast of Vancouver Island in British Columbia. The dead whale was transferred to Abbotsford, B.C., where a necropsy was performed on Christmas Day by some very dedicated people.
The immediate concern among orca observers was that the calf was one of the eight orcas born during the “baby boom” that started in December 2014. Brad Hanson of the Northwest Fisheries Science Center said that was never a real possibility. The dead calf was too young (being only a few days old) to be one of the eight Southern Residents born over the past year or so, Brad told me.
That doesn’t mean, of course, that the newborn female was not a Southern Resident orca who died before anyone spotted her with her family. But folks at the Center for Whale Research on San Juan Island says everything points to the whale being one of the seal-eating transients, also known as Bigg’s killer whales.
“Everything is screaming ‘transient,’” said Deborah Giles, research director for CWR.
Deborah has been consulting with Dave Ellifrit, a CWR field biologist who has the uncanny ability to identify individual killer whales at a glance. Dave and Deborah have seen photos of the young orca’s carcass — which, I’m sorry to say, looks to me like nothing more than a dead marine mammal.
“The shape of the jaw is more robust in a transient,” Deborah told me, adding that the overall shape of the head and the “eye patch” (an elongated white spot) appears different in transients. Other interesting facts about the young whale could be revealed in the upcoming necropsy report. I’m not sure if lab analysis of the whale’s DNA will come out at the same time, but most details are expected within two or three weeks.
Although the death of any killer whale is unfortunate, transients have been doing better overall than Southern Residents. Even with eight new births, the Southern Resident population is still four animals short of the 88 seen just five years ago. And they have a long way to go before reaching the 98 orcas reported in 2004 among the three Southern Resident pods.
For Southern Residents, prey availability has been listed as one of the likely factors for their decline. The J, K and L pods depend mainly on chinook salmon, a species listened as threatened and struggling to survive along with the orcas.
Transients, on the other hand, eat mainly marine mammals, which remain in plentiful supply. Transients that roam along the coast and enter inland waters (“inner-coast transients,” as they’re known in Canada) were increasing by about 3 percent a year up until 2011, when the population reached about 300, according to a report by Canada’s Department of Fisheries and Oceans.
Today’s population is uncertain, despite efforts to photograph and identify as many whales as possible each year, according to Jared Towers, cetacean research technician for DFO. Because of their nature, some transients spend significant time in remote areas where they may not be seen by anyone.
Several older transients among this population have died in recent years, countering the effect of increasing births, Jared told me. Still, with an abundance of marine mammals, particularly harbor seals, the population may still have room to grow.
Another group of rarely seen transients is known as “outer-coast transients.” This group, which may include transients reported in California, is estimated at more than 200 animals, although the estimate is less certain than for the inner-coast groups. For details, check out the 2012 research report by DFO (PDF 2.1 mb).
More on tagging study
Since 2011, studies using satellite tags have revealed the winter movements of the Southern Resident orcas as well as some of their favorite feeding grounds. The data are still being gathered and compiled, but they could point to coastal areas that should be protected as prime habitat for the whales, according to Brad Hanson.
This year’s data could provide additional information about how the whales respond to strong El Nino conditions in the North Pacific, which could affect prey availability, Brad told me.
The tag was attached to K-33 while the orcas were offshore of North Kitsap (see map). Over the next day or so, K pod traveled out through the Strait of Juan de Fuca and remained just outside the entrance to the Pacific Ocean.
Perhaps those K pod whales were waiting there for another group of four orcas from K pod, known as the K-14 matriline. It turns out that the K-14s were hanging out with J-pod whales, who were heading west to join them, according to reports on Saturday by the Center for Whale Research.
Weather on the coast has been horrendous of late, Brad said, but it would be nice to get some eyes on the water to see which whales are traveling with the tagged orca, K-33. Cascadia Research Collective, based in Olympia, is part of the effort, along with the University of Alaska. Supplemental funding has been provided by the U.S. Navy.
Additional satellite tags may be deployed later to track the spring movements of the whales before they return to Puget Sound in late spring. For information about the tagging project, visit the webpage “NOAA’s Southern Resident killer whale tagging.”