An interesting read. Don't know how close they are to extinction.
http://www.flmnh.ufl.edu/fish/sharks/InNews/sixgill2006.htmlSixgill Shark: Puget Sound’s Deep, Dark Secret
May 31, 2006
Release from: Ross Anderson
Port Townsend Leader (Washington)
Light and color wane rapidly in the depths of Puget Sound. At 30 feet beneath the surface, reds and yellows disappear, followed by greens and blues. At 90 feet, roughly the width of Water Street, the world dims to murky shades of gray and black.
This is where one enters the realm of the sixgill shark.
Don Zahn, a nuclear operator from Richland, has been diving for many years, so he knew what to expect last fall when he and a friend stepped off a charter dive boat in Hood Canal, south of Brinnon, and descended slowly down a steep, submarine ridge. They planned a deep, “technical dive,” using a special mix of compressed air, submersible cameras and lights.
At 70 feet, they were looking for octopus, wolf eel and giant lingcod that prefer those depths. At 90 feet, they spotted a dark figure moving slowly through the murk. An enormous lingcod?
The fish turned, and Zahn switched on his camera lights, transforming the grayness into a mini football stadium. And he nearly swallowed his regulator. He was face-to-face, or jaw-to-Jaws, with a 7-foot shark.
He acknowledges he was shocked. But he had the presence of mind to keep his camera running – even when the creature swam between the two divers.
“He never did anything threatening,” Zahn says. “He was moving pretty slowly, almost casual. I think he was oblivious to us.”
The waters around here are notoriously cold, but they’re supposed to be home to familiar, even romantic critters – silvery salmon and crowd-pleasing orcas. The only sharks we see are those pesky dogfish that show up on hooks intended for prized kings and cohos.
But in recent years, divers and scientists have been probing deeper into the Sound. And they’re learning that Puget Sound is also home to who-knows-how-many sixgill sharks, a 200-million-year-old species that resembles its more notorious cousins.
Based on the experience of Zahn and other divers, sixgills have no appetite for people. But they certainly have the equipment to do some damage – big spooky eyes, gaping jaws with jagged teeth and a streamlined torso reputed to reach the lengths of automobiles.
Don Coleman, who runs a dive charter boat out of Pleasant Harbor, south of Brinnon, counted at least eight different sixgill sightings by divers from his boat last year. Local dive shop operator Mark Peil and a buddy encountered one on a night dive in Discovery Bay. Yet another 7-footer washed up on the shore of Point Hudson last year and was turned over to the Seattle Aquarium, which still keeps the carcass in its freezer.
Sixgills are rarely seen because they are bottom dwellers that favor darkness. Divers find them – or are found – in deep water such as Hood Canal and Discovery Bay, or in shallower depths on night dives, when the sharks come up to feed.
For years, sixgill sharks were the stuff of local legends – Puget Sound’s answer to the Loch Ness monster. A generation ago, an eccentric Seattle reporter named John O’Ryan talked the Post-Intelligencer into sending him out to catch one. For days, he floated around the Sound in a small boat equipped with fishing gear, sending back reports on his quest. But nary a nibble.
In summer 2000, however, amateur fishermen hooked four sixgills within a week while night fishing from a West Seattle pier.
Biologists were alarmed. Shark populations around the world have been depleted by over-fishing, and nobody wants to see it happen here. So the state acted quickly to prohibit fishing for them. And that ban continues.
But some biologists reasoned that if more than one shark was hooked in the same place, there could be a heck of a lot of them out there.
So the Seattle Aquarium teamed up with state and federal agencies to find out. Using rebar and cable, scientists assembled a crude, 4-by-2-foot shark-feeding station on the seabottom beneath the aquarium, and hooked up a time-lapse video system. For bait, they used frozen clumps of fresh and decayed salmon, dogfish and bits of octopus. Then they waited.
But not for long. The station was an immediate success, with nightly visits from sixgill sharks. They kept coming even when researchers went down to introduce themselves.
“Mostly we see 6- and 7-footers,” says aquarium biologist Jeff Christiansen. “But we see the occasional big guy – 10 to 12 feet.”
Meanwhile, researchers chartered a fishing boat and began catching sharks on longline gear – miles of line with baited hooks strewn along the bottom of the Sound. Over time, they caught more than 200 sixgills, keeping a few for analysis, while the others were measured, equipped with numbered tags attached to their dorsal fins, and released back to the sea.
Gradually, the research is adding to our limited knowledge of an amazingly resilient creature that has been swimming the world’s oceans for some 200 million years.
Shawn Larson, a curator at the Seattle Aquarium, describes the bluntnose sixgill shark, Hexanchus griseus, as a slow-growing, long-lived species that is found in both warm and temperate oceans around the globe. They’re big – up to 16 feet, with undocumented reports of specimens well over 20 feet. Males mature at about 9 feet and females at about 13 feet.
But most of the sharks encountered here are somewhat smaller, about 7 to 11 feet, and there are few mature males. This, Larson says, suggests that Puget Sound may be a nursery area for young sixgills, which migrate out to the ocean as they mature.
So it’s safe to assume that we have some mighty big critters swimming past Port Townsend beaches on their way to who-knows-where.
While they seem to be more docile than great whites, they actually have bigger jaws, Larson reports. Appetite-wise, they appear to be “opportunists,” eating fish, octopus, dead or injured seals, whatever is available. “Just about everything has been found in their stomachs,” she adds.
Except people, that is. “They certainly could attack a human, but we’re probably outside their prey range,” Larson says.
They also have a different feeding strategy. While great whites “strike fast,” sixgills use more stealth, biting and sawing their prey with serrated teeth.
Based on analysis of tissue samples, scientists believe the sharks in Puget Sound are related – an extended family estimated at about 8,000 adult sharks. That could be the adult population for Puget Sound or for a larger area. It is also a very tentative estimate and probably a conservative one, she adds.
So the research continues. But we can be assured of one thing: Every time we leave the docks of our fair city, we are passing within a few feet of some king-sized toothy critters who are far less impressed with us than we are with them.
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