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Culprits Marked for Lifeby Cassandra ProfitaThe Daily Astorian, October 3, 2006 |
ODFW branding keeps track of sea lions' movement
It's 6:30 a.m. in Astoria's East Mooring Basin. The sun is just coming up, boats are leaving the harbor for a day of fishing, and six men armed with wooden planks are pounding the docks and banging on cage walls.
They sneak up and drop the cage door on 11 California sea lions lying on a floating trap in the harbor. Now the men, all employees of the Oregon Department of Fish and Wildlife, are trying to corral the animals into a series of smaller cages tied together on a connecting barge, where hot branding irons are waiting to number their hides.
A cacophony of barking fills the harbor from the dozens of sea lions lying on the dock nearby. California sea lions are a type of marine mammal called a pinniped, and hundreds of them travel up the Columbia River every year to find food in between mating seasons. The Port of Astoria has recently conceded an entire dock, called the O-dock, to these hefty pinnipeds, some weighing as much as 800 pounds.
As their numbers grow, they increase their claim on docks in the harbor and their intolerance for people trying to shoo them away.
Tracking their movements
The floating ODFW cage sits beside the O-dock, luring sea lions to sleep on it at night so crews can catch them in the morning and brand them for tracking purposes.
When the cage door slams shut, the sea lions inside waddle and flop together in a corner, their sack-like bodies piled on top of one another as their whiskered faces yelp and bark.
The men, led by ODFW biologist Matt Tennis, bang on the sides of the cage to scare the sea lions into a smaller trap on the barge, where the branding takes place.
The first sea lion to go onto the barge is often a veteran, one that's already been branded, according to Tennis.
"That shows me the procedure isn't harsh on them," he said. "Usually, a pilot sea lion will lead the others through. One has been through 17 times. It's the naive ones that are scared; they haven't been through yet."
When an unmarked sea lion passes through the cages on the barge, he lands in the metal claws of a collapsible trap that looks like two warped bike racks fitted together on a hinge. He groans and squirms as the bars close down on him.
The trap holds the animal in place while ODFW workers take measurements and attach tags to both of his flippers. The back quarter of the trap is then opened to reveal a section of the sea lion's backside.
Tennis stands on top of the trap and steadies the hide with his foot while Bucky Barnett hands him a glowing red branding iron. The hot metal hisses as it touches the sea lion's fur, and an acrid, yellow smoke billows out from the trap and hovers over the barge.
The sea lion is quiet as Tennis burns a permanent "C" into his skin. Tennis proceeds to burn the numbers 5, 8 and 3 onto the animal's back, each with a separate branding iron - none of them eliciting so much as a groan.
When the branding is done, officials open the claws of the trap, and C583 hops out and splashes off the barge. From now on, this sea lion will be known as the 583rd captured on the Columbia River since the ODFW started the branding program in 1997.
Why brand a sea lion?
As the original sea lion project leader in Astoria, Barnett started studying the impact of fishermen on sea lions for ODFW in 1990. But over the years the key issue has become how sea lions are affecting salmon.
Sea lions are protected under the Marine Mammal Protection Act, which imposes strict rules on how they can be handled. However, certain sea lions, like the ones that have been preying on fragile salmon runs passing through Bonneville Dam, could qualify for an exception under the law. And the branding program helps officials identify the culprits.
"That's really what started the (branding) program. We wanted to see which ones were the bad guys," he said. "It quickly became 'We're not too worried about marine mammals, we're worried about the fish.' You had protected animals versus endangered salmon."
With the permanent brands on their backs, the individual sea lions preying on salmon can be studied year after year and targeted for federal, and possibly lethal, removal.
Program director Robin Brown, a biologist with ODFW, said sea lions can pretty much wriggle out of any external tag, and they shed anything put on their fur when they molt. He said the branding method is objectionable to some people, but it is the only way to make a permanent mark and study the individuals over longer periods of time.
"These animals are so tough," he said. "If you think about the environments they live in ... all through winter, they climb up on rocks that would cut you and I to pieces. Their hide is really strong. This does not have a negative effect on their health or survival."
The branding program has helped the U.S. Army Corps of Engineers count the number of sea lions at Bonneville each year and estimate the impact they are having on salmon. This year, data indicates 85 individual sea lions picked off 2.8 percent of the spring salmon run at the dam, not including predation rates on more than 100 river miles leading up to it.
Garth Griffin, a fish biologist with National Oceanic and Atmospheric Administration, said that number has gotten a lot of people's attention.
"We don't know precisely how to attribute the range of factors for the decline of salmon, but every percentage of mortality is an impact" he said. "There is huge effort and energy involved in fish management just to adjust tenths or a single percentage point for survival. A lot of people are concerned about predation rates."
The infamous C404
It's not all sea lions that have a taste for salmon, according to Tennis. But the ones that do "those are the ones you see at Bonneville Dam year after year," he said.
Data show the sea lions who travel 146 miles up the Columbia River to feast near the fish ladders return the next year, and they often bring their friends along.
"We're still getting more each year," said Corps spokeswoman Diana Rouchel. "The number returning to Bonneville has been going up and up and up."
But sea lion C404 has been the worst repeat offender of all. Two years ago, he shocked officials by being the first to find his own private dining room at Bonneville. The Corps watched as he led other sea lions closer and closer to the fish ladders before he himself climbed in.
Last year, the Corps spent $1 million to design and construct Sea Lion Exclusion Devices for the dam, which would allow fish to pass through but not the salmon-grubbing pinnipeds.
"It worked great, except C404 was just a little two skinny," said Rouchel. "He managed to get himself into the fish ladders again this year."
C404 is one of 80 to 100 sea lions targeted for lethal removal. The lethal removal process can take years and will not by itself save salmon runs, but the efforts at Astoria's East Mooring Basin have already helped, according to Brown.
"Clearly they will use that information to identify the offending individual," he said.
The barking continues
Whereas the branding program could help protect salmon runs, it won't eliminate the crowd of loud and smelly sea lions that hauls out on the docks in Astoria, lying flank-to-flank and covering sections where no boats are tied.
The sea lions not only cost the port money in lost dock fees, they also leave a mess and recently broke the gangway leading to the O-dock with their heft. A fire started in June when workers were trying to cut the remaining half of the wooden ramp from the pier.
Harbormaster Ken Smith has tried to chase these animals off, but they grow more and more tolerant of harassment as time goes on.
Picture him waving a 3-foot-long pipe in the air like a madman, banging it against dock posts and charging at a fleet of the lounging mammals, who roll and groan defiantly in front of him. Under the federal rules, that is all Smith can do to keep the animals away from the East Mooring Basin.
As he approaches them, the animals splash heavily left and right into the water, and the dock jolts upwards about a foot to its proper height.
They're gone. Their slick black heads bob in the water as they swim away.
"They'll be back in five minutes," Smith says.
As soon as he turns his back, the bravest of the group hops right back up.
"It's terrible," said Smith, "They brand them just to keep an eye on them. They need to get rid of them."
Smith said if the sea lions weren't protected by the Marine Mammal Protection Act, the government could hire a sea lion hunter to control the populations as they did with the harbor seals up until the early 1980s.
"They know what they need to do, but they can't do it under the current laws," he said.
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