One of the most closely studied groups of killer whales in the world spends most of the year in Puget Sound, but during its annual trek to the central California coast, the group passes through North Coast waters.
When the group of 18 to 20 whales, known as "K pod," passed Crescent City on Monday, local biologists enjoyed a rare encounter with them.
Through a network of West Coast whale researchers, Arcata-based biologist Jeff Jacobsen, was asked to get on the ocean to find K pod, specifically to check the health of a whale that was tagged with a GPS transmitter while in Puget Sound on Dec. 29.
"We found the needle in the haystack," said Darell Warnock, a Hiouchi-based biologist and photographer who accompanied Jacobsen on the boat, taking photos of the orcas. "The ocean is huge and to find an individual like that is totally amazing."
A land-based biologist, Ken Balcomb, who has studied K pod for roughly 40 years, tracked the killer whales' current GPS position via his computer, relaying the coordinates to Jacobsen and Warnock. But even a very good GPS coordinate can easily be off by 100 meters, Jacobsen said.
Jacobsen and Warnock met K pod just north of St. George Reef. When the whales reached the reef, several of them started breaching, possibly rousing themselves from cruise control for a chow session.
"They were jumping on the kelp beds, which could coax salmon out of the kelp beds. It could have been related to hunting or just a rouser to go fishing," Jacobsen said.
Warnock tried desperately to photograph the huge display of breaching and tail slapping, but the rainy, windy conditions made it difficult.
"Every time I lifted my lens it was coated with rainwater. It was totally frustrating for me," Warnock said. " There were times when I just put the camera away and just watched."
Jacobsen and Warnock identified the orca with the GPS transmitter and found that it was still securely attached to the dorsal fin, and the whale appeared to be in good health.
On Tuesday, Jacobsen took his boat out again to find the whales. This time, Balcomb observed from Table Bluff County Park in Humboldt County and quickly helped Jacobsen locate the whales.
"They are travelling within three miles of shore,doing about three knots of speed all the way down, except here in Eureka when they get into a bunch of salmon," Jacobsen said.
While the group lingered outside Humboldt Bay on Tuesday, scientists collected unprecedented data on what the orcas eat during their trek south.
Killer whales are distinguished by their diet, and although it was known that the K pod whales are a salmon-eating bunch, what they eat while travelling south has never been documented.
"We collected the first sample ever yesterday," Jacobsen said on Wednesday. "They were split up foraging just south of the jetty.One little juvenile lifted its head near surface and I saw a salmon head in it's mouth. So we went over by that spot and sure enough there were a bunch of silvery salmon scales."
The salmon scales and fecal matter collected will be sent to a lab to determine which stock of salmon (from which river) the orcas were munching, Jacobsen said.
That information is pertinent to scientists who are not sure why this group of whales, primarily a resident population of Puget Sound, takes trips south to Monterey Bay and the Farallon Islands, Jacobsen said.
The salmon diet of K pod is a significant characteristic. There are three ecotypes of orcas in the Pacific Ocean largely defined by diet: fish (i.e. salmon), marine mammals (i.e. seals and sea lions) and an off-shore group that primarily feeds on sharks, Jacobsen said.
"Maybe they are coming down here because of the salmon stock," Jacobsen said, adding that salmon in the Puget Sound, near the urban centers of Seattle and Vancouver, B.C., are highly contaminated. Because the orcas eat the salmon, they are also contaminated."They are so contaminated with PCBs that they exceed toxic waste levels.It's dangerous to touch them if they wash up on the beach."
The satellite-tracked trek of K pod can be found on the Northwest Fisheries Science Center website,www.nwfsc.noaa.gov, by searching "Southern resident Killer whale satellite tagging."
To help scientists track the population, report orca sightings to the orca hotline: 1-866-ORCANET.
Although K pod may be found right now, killer whale sightingsare rare.
"I've been out on the ocean for 15 years looking at marbled murrelets on the Oregon and California coast, and I've never seen orca swimming," Warnock said-until this week.
Reach Adam Spencer at firstname.lastname@example.org.