Scientists search for Alaska's elusive octopus

Posted: Monday, July 16, 2001

ANCHORAGE (AP) -- Just where would a shrewd, boneless predator with keen eyesight, eight arms and 2,240 suckers hole up during low tide?

Carrying a driftwood spear for probing the lair of the world's craftiest mollusk, biologist David Scheel squinted under his floppy hat and scanned a broad beach of boulders and drippy kelp near Port Graham on the far side of Kachemak Bay.

''I know one of these rocks had an octopus under it,'' Scheel said. ''I just can't remember which one it was.''

Octopus aren't supposed to live so high on the beach. But years earlier, a local Native hunter had shown Scheel a den used by what the Alutiiq people call Amikug. The scientist eased his stick into one promising hollow where boulder met mud, cocking his head as he gauged for a response.

''An octopus is the only thing that will shove the stick back out -- or play with it a little bit,'' he said.

But no one was home. Not yet.

Over the past six years, Scheel has pushed the boundaries of what's known about the giant Pacific octopus in Alaska, documenting for the first time where it lives and what it likes to eat in Prince William Sound and lower Cook Inlet.

Among other things, he and his co-researchers found that local octopuses often prefer the dry-now, submerged-later intertidal zone, contradicting a long-held assumption that the species sticks to deep water. It's a strategy that might keep them from becoming chewy snacks for sea otters.

Yet much about the weird, mythic creature remains an enigma. No one knows why population levels seem to be declining, for instance, or how they might be accurately monitored by people.

''What I'm trying to learn is what regulates the number of octopus,'' Scheel said. Is it habitat? Food supply? Birth rate? Predation?

Following his first year as assistant professor at Alaska Pacific University's new marine science program, Scheel returned to Kachemak Bay for a few weeks at the end of May with his wife, plant ecologist Tania Vincent, his young daughter and APU senior Peter Plywaczewski to search for more answers.

He didn't have far to look.

Scheel and Plywaczewski walked the beach, uncovering craggy boulders and searching tide pools. At first they found only collapsing sea anemones and squadrons of tiny scrambling crabs.

Then Scheel stooped by a little cavern rimmed with sand and a midden of fresh shells. Some of the shells contained hair-line slits -- an indication that some octopus had ''drilled'' them with a special organ called a radula, then softened the inner tissue with enzymes from its saliva. Other shells appeared to have been crunched open by an octopus' hard beak, then scoured clean.

Scheel probed the hole with the stick.

Something grabbed on.

''Oh yeah,'' he said.

A few moments later, after the tide had risen a few more inches, Scheel blew a skin irritant of diluted chlorine into the hole through a plastic tube. Seconds later, a giant Pacific octopus began to ooze into view, one arm at a time.

Soon Scheel would be scooping it up in his palms and slipping it into a mesh bag, where the animal would collapse into a wad the size of a volleyball. He would wash it, measure its mantle and the distance between eyes. The 2 1/2 pound female was about a year old, with eight healthy limbs and a taste for tiny crabs. When released, it would fast disappear into the kelp, shifting the mottled red of its skin, chameleonlike, to match the background.

But for a moment, Scheel and Plywaczewski just watched.

Festooned with about 280 oval suckers, the first reddish arm unraveled from the hole. Another arm unrolled to the right, then another to the left.

Like the fingers of a climber blindly exploring a rock face for a place to grip, the flexible arms seemed to pat down the floor of the pool, probably ''tasting'' out an escape route with its suckers, each far more sensitive than a human tongue. Then they clamped down. In a smooth motion, the octopus' main body slipped into the open, its inscrutable eyes narrowed to slits. All eight legs spread out, like the rays of a star. It was launched, moving fast toward the open sea.

''What a beautiful little animal,'' Scheel said.

Then he snatched it from the pool.

Long a source of subsistence food for Alaska Natives and an important player in near-shore ecology, Great Pacific octopuses have rarely been studied in Alaska. They're rarely harvested commercially in local waters. No one has population numbers or a full understanding of their life cycle.

That began to change in 1995. At the urging of several Native leaders concerned that the octopuses seemed more scarce since the Exxon Valdez oil spill, the oil spill trustees council invited proposals to investigate the status of octopuses in the Sound and other local waters. Scheel, then working at the Prince William Sound Science Center, applied for the grant.

With about $225,000 in funding from the trustees, Scheel organized a 15-member team that spent two seasons searching for octopuses at dozens of locations throughout Prince William Sound and Kachemak Bay. They looked under rocks and sent divers down to nearly 100 feet. They even used a minisub to track them. No one had ever done such research in Alaska before, Scheel said.

''We'd mark on dens with street address numbers, glued on with epoxy,'' Scheel said.

They tracked five octopuses with sonic tags to see where they went. They cataloged what they ate -- a wide range of crabs, bivalves and chitons. Octopus parts were found in the stomachs of 43 fish species, particular dogfish sharks. Sea otters and harbor seals ate them, too.

Scheel also worked with Native foragers and fishermen from Tatitlek, Chenega Bay and Port Graham, going into the field and listening to their instructions about octopus habitat and behavior.

Conventional octopus wisdom states that the creatures stay deep and get bigger as you go down. But Scheel's team found that local octopus seemed to prefer intertidal mud beaches and dense kelp beds, possibly to avoid predators. About 80 percent of octopuses were found in less than 15 feet of water.

''They really do use the intertidal,'' Scheel said. ''And I think they live in it -- they're not just there incidentally.''

But the team was unable to explain why the species might be declining throughout its Pacific Rim range. One theory hinged on sea otters, present in Prince William Sound but absent from British Columbia.

On the May trip to Kachemak Bay Scheel caught six octopuses with crab pots in deep water in the first four days. If he could get funding, Scheel would come back next year, catch octopuses deep and release them shallow with tags that emit a sound.

''Then we'll follow them with the submersible and see where they go,'' he said. ''Nobody's ever done it before, and I've been saying for years we should just switch some and see what happens.''

Though Scheel proved he could find octopuses deep, it didn't always go smoothly. One 65-pounder trapped about 200 feet down in Eldred Passage emerged from the pot and ''fought like a mad man,'' Scheel said.

Its arms whipped out, suckering the deck and grabbing rails and wrapping around human legs.

''You pull them up like a bath mat,'' Scheel said. ''You pull them up one sucker at a time, and that works great except that they have eight legs and you have only two.''

The two men wrestled the octopus into the pot so they could return it to the water. ''When they get that big, they're pretty strong,'' Scheel said. ''But they tire easily'' due to copper-based blood that's not as efficient as the iron-based blood of mammals.

On most mornings, Scheel and Plywaczewski towed a fine-mesh net behind the 27-foot Islander with Capt. Bruce Lozekar at the wheel. Intended to sample the top few centimeters of ocean surface for plankton, the results from the tows were bottled and examined each night under the microscope. In theory, Scheel would find a smattering of tiny baby octopuses among the copepods, crab larvae and other creatures.

So far no octopuses.

''Could mean the season is wrong,'' Scheel said. ''Could mean I'm towing in the wrong places. Could even mean I'm towing at the wrong depth.''

But that's OK, Scheel said.

''It's no fun doing research if the answers are all known already.''

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