Story last updated at 11:34 a.m. Friday, August 2, 2002

Sea lion death mystifies
by Sepp Jannotta
Staff Writer

photo: news
  Photo by Sepp Jannotta, Homer News
Vaterinary pathologist Kathy Burek examines the mouth of a dead sea lion that was found floating in Kachemak Bay on July 24. She extracted a tooth, which will help determing the age of the 1,400-pound bull.  
A July 24 halibut charter aboard the Gold 'n Sea ended with an unusual haul when the boat chanced upon a dead Steller sea lion as it was motoring for the Homer Spit.

Following a cell phone call to Pratt Museum Collections Director Betsy Webb, skipper Dick Koskovich put a rope around the enormous creature and towed it back to the harbor.

A little more than 12 hours later, the animal lay on the asphalt behind the museum where veterinary pathologist Kathy Burek was preparing for a National Marine Fisheries Service-ordered necropsy to help determine the cause of death. The preliminary examination showed the sea lion was malnourished.

While Burek and state Department of Fish and Game graduate intern Julie Richmond set about measuring the carcass and taking tissue samples, a group of middle school kids from the museum's Summer Adventure Program quietly videotaped, sketched and generally absorbed the somewhat grisly process unfolding before them.

The museum and NMFS prized the relatively fresh carcass because it was an adult.

For Webb, the sea lion would provide a hands-on educational project that would ultimately make an excellent addition to the museum's collection of marine mammal skeletons.

For the marine biologists of NMFS, the carcass meant rare forensic data on an adult sea lion that had been, until recently, foraging in the waters of Kachemak Bay, Cook Inlet and the Gulf of Alaska.

"It's a really unusual opportunity to get a look at an animal this age, and it's so unusual to get a specimen that is in such good condition," Burek said as she probed the Steller's gum line looking for a suitable tooth to extract. After lab analysis, the tooth will give an exact age of the Steller.

On scene, Burek and Richmond relayed the more rudimentary observations -- the sea lion was a male, weighing more than 1,400 pounds and measuring just shy of 10 feet in length. Typically, a healthy full-grown bull would weigh closer to 2,000 pounds, Burek said.

"You can see the blubber layer is very thin," she added, cutting off a swatch of hide that was marked with some prominent scars.

The tissue samples collected from the hide, muscles and from most of the vital organs will help pinpoint the cause of death, Burek said. Beyond that, data from lab tests will ultimately tell a story about what kind of life the animal led, from details about its diet to the presence of harmful environmental toxins or disease in its body.

But given the bull's empty digestive tract, Burek's first guess on the sea lion's mortality was starvation.

According to Burek, one hypothesis might be that this particular bull was unable to recover from the period of fasting and physical strain that takes place as the males stake out and tenaciously fight for territory in the rookery. She said some studies have found that, during the weeks-long mating season, a territorial bull might lose up to a third of its body weight.

Burek thought the scars on the animal's neck were consistent with the wounds of mating season battles, though she could not definitively rule out a run-in with a boat propeller. In either case, in a weakened condition, a small wound might become a real problem.

Jim Wisher, a NMFS enforcement officer, said he was amazed that a marine mammal could want for food in the local waters.

"How can an animal starve to death in Kachemak Bay, for crying out loud?" he asked. "There's all kinds of things for a Steller to eat out there."

Wisher said he thought it was likely that this sea lion was one of the big males that took up residence at the Spit each July, feeding and hauling out in the small boat harbor.

Before harbor officials and NMFS officers began writing tickets to people for feeding sea lions, an activity prohibited by the national Marine Mammal Protection Act, the animals were well fed as the halibut fleet cleaned its daily catch. Both Wisher and Harbormaster Bill Abbott said that despite rules against dumping fish remains in the harbor, it is not unusual for some people to deliberately attract the animals with fish carcasses.

The number of sea lions in the harbor has been slowly decreasing since the officers began consistently enforcing the rules, Abbott said.

When an aggressive bull lunged onto a harbor float and sent a woman sprawling into her grandchild, the harbor officials got tough with a zero-tolerance policy for sea lions lounging on harbor floats. In an unprecedented and federally sanctioned effort to control the creatures, which are officially listed as endangered, harbor officers employed pistol-fired "seal banger" fire crackers to drive the animals from the harbor.

Wisher said it was his opinion that this particular bull had fared poorly after being cutoff from its food source in the harbor, where it had probably feasted for several seasons.

"It's my belief that a lot of times the kind of sea lions that would go into a boat harbor" are not most productive hunters, Wisher said. "Once (the public) stopped feeding them, they had to go back out and compete with other, stronger sea lions in the bay."

Whatever the cause of death, Abbott said, he is keeping his fingers crossed that this bull was one of the troublesome harbor residents.

Harbor officials have been most concerned with a pair of males who last summer repeatedly showed aggressive behavior around the floats. Abbott said he doesn't particularly mind sea lions in the harbor as long as they aren't hauling out or endangering anyone.

"In any case, we're hoping that this (dead sea lion) took care of our sea lion problem," Abbott said, adding that there have been no reports of sea lions since May. "Typically by now they'd have started coming back."

Abbott said he'd heard a report of two other dead Steller sea lions in Kachemak Bay in recent weeks. Wisher, who officially tracks cases of marine mammal mortality, said he learned of a dead harbor seal and a dead harbor porpoise but no other sea lions.