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Beachcombing for Sea Lion Satellite Tags
Perseverance Turns Up Valuable Device
As a fisheries biologist with the Alaska Department of Fish and Game, Scott Walker doesn’t often work with sea lions. But his curiosity and fascination with beachcombing led to the recovery in September of a pack of valuable scientific instruments that was glued to the fur of a Steller sea lion 145 miles up the Columbia River at Bonneville Dam in May – a sea lion that traveled close to 1,000 miles to Southeast Alaska before shedding the instruments on the southwest corner of Dall Island.
Walker lives in Ketchikan and manages commercial fisheries in the southern portion of Southeast Alaska. One of his duties is to fly in fixed wing aircraft, counting commercial fishing boats and estimating the numbers of returning pink salmon to areas streams. At times he assists other divisions by photographing areas of interest from the air. On June 26, 2012, Lauri Jemison, a sea lion biologist with the Wildlife Conservation Division e-mailed Walker the following message:
I realize this is a long shot but…if you’re flying telemetry down near Dall Island, and happen to have a receiver that can pick up 164 mHz frequencies, please read on. There is an adult male Steller sea lion that was tagged by Steve Jeffries (Washington Dept. of Fish and Wildlife) down at the Bonneville Dam several months ago that has made his way north to Dall Island. This animal has several tags glued onto his back – a SPLASH tag, a VHF tag & other instruments – these are packaged in a floatation material and ideally once shed, will be picked up by someone and returned. Of course, expecting someone to happen upon the tag down in WA seems reasonable, but this one male has come north, so Steve J. has asked us to keep an eye out.
If any of you are flying telemetry flights near Dall Island and are able to pick up 164 frequencies, perhaps you’d be willing to listen for animal O35; his frequency is: 164.524 mHz. We’re hoping O35 heads over to Cape Addington or out to Forrester where we have folks that will be in the area and may be able to spot him.
Jemison provided a map showing the sea lion’s route north (see the sidebar). The animal had traveled almost 1,000 miles in just a few weeks from the Columbia River, and was located by satellite fixes near the southwestern corner of Dall Island, about 60 miles southwest of Ketchikan. The VHF tag Jemison referred to, glued to the sea lion, would enable a biologist to pinpoint the animal’s location – or at least the location of the floatation pack with instruments affixed to the animal.
Walker didn’t have a VHF telemetry receiver and had never used one so he just ignored the email at first. Using a receiver to interpret the “beeps” that get louder and softer as you approach the transmitter takes some practice and Walker didn’t think he could help.
A few weeks later Walker was discussing sea lions with Jemison and he volunteered to assist Jessica Carie, a sea lion researcher, with a skiff survey of sea lions on the West Rock haul out near the Canadian border about 40 miles south of Ketchikan.
They skiffed out to West Rock on July 13 and saw a sea lion with a rectangular bare patch on its back. The animal was branded with the number O35 and had a red tag that looked like flagging. Upon returning to Ketchikan and reporting to Jemison they realized that O35 was the missing sea lion - and his floatation pack with instruments was gone.
Jemison immediately contacted Steve Jeffries who became very interested in the missing sea lion tag. Jeffries had captured and tagged Steller sea lion O35 on May 1, 2012 at Bonneville Dam on the Columbia River, one of three Steller and five California sea lions tagged there last spring.
“That sea lion had had about $10,000 worth of instruments on a floatation pack glued to his back, and we really wanted them back,” Jeffries said. The SPLASH tag is a miniature waterproof wildlife computer that records and stores information on the animal’s activity - dive depths and profiles, a freshwater/saltwater sensor measuring conductivity (essentially the salinity of the water the animal is in), and water temperature. The instrument must be retrieved in order to access archived data. It also has a GPS function, which transmits location data via satellite so the animal could be tracked before the pack was recovered, and a VHF transmitter for on-the-ground recovery effort. Lastly, the pack contained a miniature Vemco 35 acoustic receiver/transmitter device that listens and records signals from other acoustically tagged animals like fish. A wide variety of west coast researchers have deployed thousands of acoustic tags that transmit a unique coded signal. If the sea lion encountered a salmon, sturgeon, other fish or marine animal with an acoustic tag, it would record the code, and the place and time of the encounter. That also needed to be recovered to download the data.
Jeffries said that Steller sea lions started showing up at Bonneville Dam in 2002, feeding on salmon and sturgeon in areas below the dam. California sea lions swim up the river as well. As many as 60 Steller sea lions are now showing up annually in the winter and spring below the dam and are even hauling out at a site 15 miles downriver.
“We already knew some of these animals at Bonneville are from Southeast Alaska,” he said. “Another one traveled to Sitka Sound and was photographed there interacting with the herring fishery.”
Jeffries knew tagging an animal that might swim more than 1,000 miles across fairly remote and unpopulated areas was a risk. The floatation packs are designed to come off within a year or less (as the animals go through their annual molt), float to shore, be found by beachcombers and turned in. He said along the Oregon, Washington and California coasts, “where everyone beachcombs,” the odds are very good that the packs are recovered and returned once they come off. The odds for recovery from Southeast Alaska, not so much.
“The instrument packs have floatation and they’re brightly colored,” he said. “They’re designed for beachcombers to find them. We call it going on an Easter egg hunt. If you beachcomb you know - you’re walking along, and anything that’s out of place jumps out. We paint them so they ‘glow’ with a bright color in the kelp and beach debris, and if they wash ashore in a place where people beachcomb, you get them back. We also know where they are by the GPS location, and we can go out and recover them as well.”
The GPS tag transmits a signal every 15 minutes and the VHF transmitter can be detected by a biologist with a telemetry receiver in a small plane, as Jemison had indicated. Jeffries knew if the tag wound up on a remote beach off the coast of British Columbia or Southeast Alaska, finding someone to help, and flying out in a plane or helicopter to recover it could be very expensive.
Jeffries said for a couple weeks after he was tagged, sea lion O35 moved regularly between a feeding area right below the dam and a haulout site about 15 miles downriver. Then he swam 145 miles to the mouth of the Columbia and headed north.
“It traveled from the Columbia River to Southeast Alaska in about a week,” Jeffries said. “Once it decided to go it really went.”
The animal spent most of June at a haulout southeast of Ketchikan, and then started moving back and forth from that haulout site to a foraging area near Wolk Point at the southwestern end of Dall Island. Walker noted that chum salmon were especially abundant in the area in early July. An estimated 4.5 million chum salmon swam through the area in that period, and between July 1 and July 4 purse seiners caught a record 460,000 chums in an area between West Rock and Wolk Harbor.
Sometime before July 13, he shed the tag, as Walker and Carie’s sighting confirmed.
Walker was now very interested in finding the tag and flew over the last known tag site with pilot Dave Doyon, the owner of Misty Fjords Air, on his next boat count near the area. The GPS data transmitted via satellite indicated the tag was somewhere on a pair of beaches connecting a rocky knoll to the southwest corner of Dall Island. But the location was not precise and encompassed several hundred square yards. After a few minutes looking at the beach it was clear that the tag couldn’t be found from the air with vision alone.
“At some point the satellite fixes are no longer going back and forth,” Jeffries said. “We know it’s somewhere near Wolk Point, we’ve got all these hits from the same latitude and longitude. It could have been on either side of the point; there were a few spots it could’ve been. And as they later learned, it was fur-side-up, so you wouldn’t see the bright color from the air.”
After telling Jeffries that he would try and locate the tag, Jeffries immediately sent Walker a cooler with all the equipment needed to find the missing tag.
Upon receiving the tracking gear, Walker was determined to find the tag. On August 18, while conducting stream surveys on Dall Island he went over the last known site of the tag using the borrowed receiver. Having never used a receiver before, Walker relied on pilot Dave Doyon to actually use the receiver. Dave has flown many hours finding bears, goats and wolves with ADFG biologists and quickly identified the beach where the tag was located. The beeps clearly located the tag on the southwest shore of Dall Island near Wolk Harbor.
Actually getting the tag off of the exposed beach was another problem. After discussing various methods of retrieving the tag it was decided to fly out the site with a helicopter to collect the tag. Having no experience with telemetry gear Walker decided it was time to bring in telemetry expert Boyd Porter. Porter is ADFG’s area wildlife biologist in Ketchikan and a former Steller sea lion researcher; he was excited to travel to a remote Alaska beach to help recover a sea lion tag.
On September 4, Walker and Porter flew out to the site with Eric Eichner who piloted the Hughes 500 helicopter chartered from Temsco Helicopters.
“It was actually upside down when we found it,” Walker said. “Boyd had found the best beep and was playing with the telemetry receiver, and I was digging around and moving logs and working up a sweat. Our pilot saunters over to where we are and points at the ground – ‘Is that it?’ He says, ‘this hairy thing?’”
The recovery was quick as the tag lay uncovered on the rocky beach right at the tide line, only about 30 feet from the back of the helicopter landing gear. After a few minutes of beachcombing, and one glass ball found by Eichner, the team headed back to Ketchikan. The tag was sent off to Jeffries the next day.
“We have all the data,” Jeffries said. “I think all that data is going to be interesting and valuable for the (Alaska) Steller people. The story has not ended yet. We’ll share that data and hopefully re-deploy the recovered pack on another Steller at Bonneville next year.”
Jeffries noted that the sea lion’s Vemco 35 had detected two different acoustically tagged green sturgeon off west coast on Vancouver Island on his trip north.
“If I could talk to the director of Alaska Fish and Game I’d have him give Scott an award,” Jeffries said. “Scott doesn’t know me, and it was awesome he was so persistent for so long. He was great.”
Jeffries said that in late October Sea Lion O35 was positively identified back in Washington in Hood Canal. He was first seen around October 15 and has been eating chum salmon amid the gillnet fleet, and at one point was hauled out with a mixed group of Steller and California sea lions on top of a Trident nuclear submarine at the Navy’s Bangor facility in Hood Canal.
One thing that was agreed upon by all is that beachcombing by helicopter is the only way to beachcomb.
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