Washed-up shark sheds light on sensitive, lethargic swimmer

TAMAR BEN-YOSEF

July 03, 2008 at 12:40PM AKST

Bob Uhl of Kotzebue doesn’t recall ever seeing a shark appear, dead or alive, in Kotzebue Sound.

Neither do other residents who stood around the decomposed carcass of a shark on Wednesday, June 11, outside the home of Guy and Christy Adams in Kotzebue.

“You can expect anything these days with global warming,” Uhl said in an interview from his summer camp in Sisaulik, near Kotzebue.

The shark is not the only strange visitor to the area’s beaches. In the last couple of years, organic material resembling air bladders has shown up on shore in Kotzebue around July. It is still unclear whether they are egg cases from fish or insects or perhaps some sort of plant.

Uhl, who has been living in Kotzebue since 1948, is the first person locals turn to with questions about anything concerning local marine life.

His interest in biology and chemistry brought him to write a 10-year journal in which he documented all he observed coming in and out of the waters from Cape Krusenstern westward and south to Kivalina.

The shark, at first mistakenly identified as a salmon shark, was odd enough to spark the interest of both Uhl and Jim Dau, a Northwest Arctic area biologist with the Department of Fish and Game.

Curious as to the species of this almost nine-foot shark, he checked the mouth for teeth, but those had either fallen out during the shark’s journey to shore or had been taken.

A quick research in a shark identification book revealed that the mysterious guest was most likely a Pacific sleeper shark — close relative or twin species of the Greenland sleeper shark, according to Bruce Wright, author of the forthcoming book “Alaska’s Predators.”

Wright knows most everything there is know about sharks, and when prompted can provide numerous stories of rare encounters, oversized sharks and the misconceptions people have about certain species.

Because no sharks have been known to appear in Kotzebue Sound, some guessed the sleeper shark to be a rare species.

Not so, according to Wright.

Apparently, the sleeper shark is far from rare and is a fan of cold water, and therefore, the Chukchi Sea, though a bit farther north that its usual habitat, is included in the shark’s range of travel, according to Wright.

A somewhat lethargic species, the Pacific sleeper usually inhabits deep waters and springs up closer to the surface only to bite a chunk out of a seal or sea lion innocently passing by, according to Wright. They also feed on other bottom feeders such as crab, squid, octopuses and triton.

“I think they are there offshore all the time,” Wright said. “But they don’t usually float when they die.”

Wright’s fascination with the species has much to do with the shark’s biology. With a pair of tiny, almost useless beady eyes, the sleeper has a sixth sense that it uses to detect prey.

“Any heartbeat or diaphragm moving gives out signals,” Wright said.

Their super-sensitive sensory system, while helpful when out for dinner, can cause a shark great stress when in the presence of humans, on the surface of the water or on land. They become so stressed that they often appear dead, according to Wright.

It is anyone’s guess as to how this shark died. By the time it washed up it was severely decomposed and appeared to have been picked at by seagulls. One possibility, according to Uhl, is that it died in waters farther south and drifted with the wind, ending up in Kotzebue.

Charlie Lean, Norton Sound Fisheries Research and Development director, said incidents of shark sightings and bycatch are increasing. Two sleeper sharks have washed up at Teller and Savoonga.

While the sleeper competes for some of the same mammals and fish sought after by fishermen and subsistence hunters, Wright stressed that their mere existence means good news.

“They are really important for maintaining a healthy and stable ecosystem,” Wright said.

“Without them, things go out of whack. If these sleeper sharks are removed, your system will go haywire and they don’t take that much prey,” he said.

Tamar Ben-Yosef can be reached at (907) 348-2419 or toll-free at (800) 770-9830, ext. 419.