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Sixgills in SeattleWhile the northwestern US city sleeps, a unique cage-diving operation is offering midnight encounters with prehistoric deep-water sharks. Words and photographs by Simon Rogerson |  | |
Photos: Simon Rogerson
How the system works
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It's nearly 2am and I'm kneeling inside
a cage at a depth of 20m, watching crabs fight over a piece of dead fish. I'm getting colder by the minute, but the 6m visibility
is better than I had expected, as this is the famously murky Puget Sound, just offshore from Seattle, the largest city in the US state of Washington. Under the orange glow of our lights, a bizarre array of nocturnal scavengers has risen from the depths of
the North Pacific, attracted by the scent of the thawing block of salmon heads tethered close to the cage.
I'd been told to look for a moving rock, so I ignore the warring crabs and concentrate on the darkness beyond. If you've ever stared at empty blue water for more than ten minutes, you'll know that it has a mildly hypnotic effect. Doing the same with black water is much worse - especially if you're already tired and cold. So when a dark shape finally emerges from the gloom, it takes a while before I realise that it is the shark I have been waiting for. It swims right past the bait and towards the cage, where I am waiting behind an open window that suddenly seems uncomfortably wide…
Although the sixgill shark (Hexanchus griseus) resembles a big dogfish, it is much more closely related to long-extinct fossil sharks dating back more than 200 million years. It derives its name from the fact that it has six gill slits, whereas all but a few modern elasmobranchs have just five.
They range throughout the deep oceans, from the tropics to the temperate zones,
but the Pacific Northwest is the only place where they are found at diver-friendly depths. There have been sightings over the border in Canada in the Strait of Georgia between Vancouver Island and the British Colombia mainland, but such encounters are rare - you can't book an appointment with a sixgill. Or so I thought, until Eric Cheng - founder of the underwater photographers' website Wetpixel - invited me to try out a new cage-diving operation.
Team Hydrus is a group of experienced Seattle-based divers who have been monitoring the sixgills of Puget Sound for several years. Using a complex baiting rig involving a cage with a high-powered lighting rig suspended above, they have created a scenario in which divers can safely observe one of the deep sea's true marvels. Safety is a key issue, because sixgills can grow to nearly 5m in length,
and although they appear sluggish, they
are capable of quick bursts of speed.
Back in the cage, the shark advanced, and time slowed. I forgot about being cold and jetlagged, focusing all my attention on the shark. It was big, at least 3m long, with a greyish-brown body and a pronounced lateral line running along its flank. It didn't strike me as being at all shark-like, as it lacked the big first dorsal fin that people associate with the classic shark shape.
It swam right at the cage, wedging its blunt nose and upper jaw between the bars. Then it did something that I thought sharks couldn't do. It reversed. Think of all the sharks you've ever seen… have you seen one go backwards on purpose? Me neither, until that night. It backed up with calm precision, then made for that worryingly wide window I mentioned earlier.
Travis Swanson, the man who devised the baiting rig, had warned me this might happen, adding that a shark in the cage was 'the worst-case scenario'. If a shark were somehow to blunder into the cage, it would be up to the diver in the large open section to block its passage with their camera. So I held up my beloved Aquatica housing and waited as the shark nosed around the front of the cage before heading back to the bait. I didn't feel cold anymore.
The sixgills weren't the only predators attracted by the bait. During the long periods I sat waiting for the main act, I
was entertained by sparring Dungeness crabs, spiny dogfish and, weirdest of all, chimaeras. If the sixgill is a prehistoric shark, chimaeras - a group of cartilaginous fish dating back 400 million years - provide a glimpse of what its ancestors may have looked like. The species I encountered -
the deep-water spotted ratfish (Hydrolagus colliei) - is a relative of sharks and rays
but looks like a visitor from another planet. Under artificial light, its eyes cast an eerie green reflection so strong that it's as if
they are beams from a torch. I didn't
know whether to photograph them or
call for an exorcist.
I don't know of anywhere else where
you can see chimaeras at such shallow depths, but the local divers are dismissive of them (hence the unromantic 'ratfish' sobriquet). I know people who do 50m dives in Norwegian fjords to find them - in the depths of winter. During a quiet period,
I got Travis's blessing to venture outside the cage and photograph the chimaeras. This proved easier than I thought, as they kept bumping into my camera's port, possibly entranced by their own reflections.
I dived like this for three nights, sleeping like a vampire during the day on a little liveaboard and having breakfast at lunchtime. As it turned out, that first electrifying encounter proved to be the best, though I was treated to some great action when a smaller sixgill ripped the bait to pieces in front of the cage. This one was completely black; the reason why they appear in different shades remains a mystery.
Interestingly, the different individuals showed identical behaviour when feeding, swimming above the bait and then bearing down on it with a vertical dive. Opening their jaws wide, they bit down on the fish, rolling their bodies like crocodiles until the flesh came away. Quite often, I saw sharks swimming around with big pieces of salmon hanging out of their mouths, occasionally with a determined Dungeness crab still clinging on.
As a diving experience, it was quite unusual, though I can see how it wouldn't necessarily be everyone's idea of fun. Afterwards, I had a day of diving during daylight with Bandito Charters (www.banditocharters.com), and found that Seattle-Tacoma has some good dive sites, even if they are a bit murky. Above all, it was a pleasure to meet the divers of the Pacific Northwest, a drysuited tribe with a great deal in common with we Brits. For once, however, I can boast that we're the ones with the better visibility.
HOW THE SYSTEM WORKS
For all the drama of my encounter, Team Hydrus' ingenious cage system allows you to see the sharks
in the safest possible conditions. A big cage is anchored into the sloping sea bed at a depth of 20m, with two taut guide ropes leading from surface buoys to the top of the cage.
Just above the bait, a lighting rig and low-light video camera are suspended from a buoyancy can, with cables running to a surface boat where a member of Team Hydrus monitors events on a video link. The same footage is transmitted by a wireless signal to
a screen on the liveaboard, so the divers will know exactly when a shark is active on the bait.
The cage itself has two openings for photographers, both of which can be closed. In case of emergency,
the entire cage can be raised to the surface by the controlled release of air into a flotation system. This has happened on one occasion, when several sharks became frenzied and it was deemed safer to ascend inside the cage.
Hydrus has several sixgill sites, and the entire
setup can be raised and moved if a given site
proves unproductive. For further details, go to
www.teamhydrus.com
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