Killer whale tracking study continues this yearJanuary 3rd, 2014 by cdunagan
UPDATE, Jan 9
L-87 and presumably J pod never headed out to the Pacific Ocean after going into the Strait of Juan de Fuca last week. Instead, they stayed around the area for a day and a half before heading up Haro Strait, spending at least two days around Canada’s Texada Island. That was similar to the previous trip up through the Strait of Georgia. Check out the latest map by the Northwest Fisheries Science Center.
Killer whale researchers are using satellites to track the movements of J pod this year, as part of an ongoing effort to understand where Puget Sound’s orcas travel in winter.
The day after Christmas, a satellite transmitter was attached to L-87, a 22-year-old male. The whale, named “Onyx,” has been traveling with J pod for at least three years.
Researchers caught up with the pod Dec. 26 in the Strait of Juan de Fuca, where the satellite tag was attached by shooting a dart into L-87’s dorsal fin.
Brad Hanson, a researcher with Northwest Fisheries Science Center, said less in known about the winter movements of J pod than either K or L pods — even though J pod has a history of spending more time in Puget Sound than the others.
As you can see from the map, the orcas traveled up into the Strait of Georgia in British Columbia, circling Texada Island before returning to Seattle. As of Wednesday night, the whales were about halfway down the Strait of Juan de Fuca on their way to the outer coast. Maps and other information about the tracking project can be found on the blog titled “2014 Southern Resident Killer Whale Satellite Tagging.”
Hanson and his crew went out to meet the whales off Edmonds on New Year’s Day and collected fish scales and fecal samples the orcas left behind. By analyzing the samples, researchers hope to learn what kinds of fish the whales are eating.
As we’ve discussed, 2013 was an unusual year for all three Southern Resident pods, which spent less time than usual in the San Juan Islands during the summer followed by shorter trips into South Puget Sound during the fall.
Brad, who has been in discussions with salmon experts, speculated that a low run of summer chinook to the Fraser River in Canada coupled with stronger-than-usual chinook runs off the Columbia River may have diverted the orcas to the ocean for longer periods,. They made occasional hunting trips to inland waters in search of prey.
Whether this unusual pattern will continue probably depends on salmon abundance this summer and fall. The Southern Residents have a strong preference for chinook salmon, but they are known to shift to chum in the fall.
Another new method of locating whales in winter has been the deployment of seven acoustic recorders along the West Coast, from Central California to the northwest corner of Washington. Hanson and his associates recently reported results from a five-year study of killer whale recordings along the coast.
Different groups of orcas can be distinguished by their unique calls, or dialects. Southern Residents, in general, were picked up on the recorder most often off the Columbia River and Westport, where they were probably preying on salmon bound for the Columbia River.
One goal of all these studies is to determine whether “critical habitat” for the orcas should be protected outside of Puget Sound. Coastal areas, including areas near the Columbia River, would seem to be good candidates for increased protection for the endangered Southern Residents. Their numbers have dwindled from 97 to 80 animals over the past eight years.
Out of 131 detections on the recorders, J pod was identified 25 times — all on recorders stationed at Cape Flattery at the entrance to the Strait of Juan de Fuca. Meanwhile, K and L pods showed up more often in waters off Southwest Washington, suggesting that the three pods may be going their own ways in winter, with J pod staying farther north. This idea could be supported with the latest satellite tracking of J pod.
Last year, a satellite tag was attached to K-25, and it remained on from Dec. 29, 2012 (Kitsap Sun, Jan. 5, 2012) through March, when another tag was attached to L-88 (Water Ways, March 5, 2013). The first tag continued transmitting until it ran out of power about April 4 (Water Ways, April 5, 2013). The second tag fell off after about a week.
Later, researchers discovered that one of the two darts on the tag attached to K-25 was still in place after the transmitter fell off. This was not something seen during extensive testing before deployment, Brad Hanson told me. He suspects that the transmitter was knocked off, perhaps by another whale. Nobody knows how long the dart will remain in place.
Since then, the tag was redesigned with a circular tab at the base of each dart. Now, if a transmitter comes off, the tab will exert drag through the water and help pull out any remaining darts.
While researchers track L-87 and J pod, they will look for opportunities to tag another K or L pod whale to compare this year’s movements to the long travels of last winter. The research team has scheduled a cruise for mid-March to follow the whales and collect additional prey samples.