October 26, 2020

On a calm September day, a group of moose hunters sat in their skiff on Iliamna Lake on the Alaska Peninsula. The men noticed what looked like two big sunken logs beneath their boat but didn’t think much of it. They focused on scanning for moose and watching a family of swans floating nearby. Suddenly, one swan vanished underwater. In a matter of seconds the rest of the flock was dragged under. The hunters watched in horror and fascination as what they thought had been sunken logs fed on the birds. One was the length and the width of their 18-foot skiff and had eyes the circumference of soccer balls. The creatures looked like giant northern pike.

Illustration by Alex Witt

Bruce Wright, a marine ecologist and apex predator specialist, recorded this account. It’s just one of many stories of what people have dubbed “the Iliamna Lake monster.” Wright is “not a big fan of cryptobiology,” but as a scientist who has studied everything from bears to sharks, he finds the stories of the monsters fascinating. The lake interests Wright as much as any mysterious beasts it may hold.  

“What’s so intriguing to me is the lake itself. Five to 8 million adult sockeye salmon come back Lake Iliamna each year,” Wright said. 

At 77 miles long, up to 1000 feet deep and with an area of roughly 1,200 square miles, Iliamna Lake is the largest lake in Alaska and the third largest in the U.S. It’s the source of the Kvichak River Watershed, which is considered the most productive freshwater habitat for Bristol Bay’s sockeye salmon. 

Looking out on the expanse of Iliamna. Photo courtesy of Chris Miller

There’s some debate as to the exact meaning of “Iliamna.” According to a newsletter published by the Yup’ik village of Igiugig, which lies at the western edge of the lake, Iliamna is “the name of a mythical great blackfish supposed to inhabit this lake, which bites holes in the bidarkas (kayaks) of bad natives.” 

Many people, from local Natives to visiting scientists, believe there’s nothing mythical about the monsters. Since well before Alaska became a state, there have been numerous reported sightings of giant fish-like creatures in the lake. There’s some variation in descriptions, but most witnesses say the creatures are dark colored, shark-like in appearance and between 10 and 20-feet long. Often there’s more than one together and frequently, the creatures are hunting. Many Natives believe the creatures to be dangerous and attracted to the color red. In 1980, the Anchorage Daily News offered a $100,000 reward during a five-month period to anyone who presented clear evidence of the monsters. No definitive proof has been made public, though there have been sightings reported most years since. Despite the lack of a carcass or verifiable photo, Wright believes there’s validity to the stories. 

Looking down on the shoreline of Lake Iliamna. Photo courtesy of Chris Miller

“I was skeptical. I’m not skeptical anymore. Every time I talk to someone who has spent time out there, they’ve seen it or know someone who has,” he said. 

For years, Wright theorized that the monsters might be Pacific sleeper sharks that adapted to living in freshwater. Now, he’s wondering if they might be a tiny population of gargantuan northern pike. Others have theorized they’re giant sturgeon. However, reports of the creatures’ predatory behavior—herding seals into shallows to hunt them and preying upon schools of sockeye salmon—don’t sound like a sturgeon. Wright came to the conclusion that only way to solve the mystery was to catch one of the monsters. 

  Around this time Wright befriended Mark Stigar, a retired colonel and former chief aviation officer for the Alaska Army National Guard, who owns a cabin on Iliamna Lake. Stigar had heard the stories for years—and having both a Baccalaureate and Master’s degree in Wildlife Biology, he was intrigued, though he took the stories with a grain of salt. Wright gave Stigar some commercial halibut longlining gear. Stigar set the gear out on the lake’s bottom at a 100-foot depth, with each of the 14 hooks baited with the head of a sockeye salmon. He’d heard of other fishermen trying to catch the monsters in the past; some claimed to hook into one of the creatures but said no line, including steel cable, was able to hold one. 

In 2017, after several summers with no action, Stigar had an experience that convinced him the monsters were real. On that day he went to check his longline set and was surprised to see that his 38-pound anchor had been dragged 50 yards.

“The line was going the opposite direction and was all tangled. Gangens were gone, severed. Metal snaps were bent in different directions and piled on top of each other,” Stigar said. 

Halibut longline gear, similar to what Stigar was using, will hold 10-foot plus sleeper sharks and halibut well over 300 pounds. Some who heard Stigar’s story theorized it could have been a seal—the lake has a population of around 400 rare freshwater seals. Stigar believes whatever moved his gear was much larger and more powerful. Instead of resetting the longline, Stigar coiled it and packed it away. Now that he knew the “monster” was real, he didn’t want to hurt or kill it.

“This could be the oldest creature on the planet. I’m not going to try to catch it anymore,” Stigar said. 

Tangled longline and a severed gangen after something big struck Mark Stigar struck Mark Stigar's longline. Photo courtesy of Mark Stigar

Wright agreed with Stigar and the men developed an underwater camera system. The contraption was deployed for the first time in the summer of 2019. 

“If anything, it’s just been fun to see what comes to the camera,” Stigar said. 

During 2020 there were three reported sightings of the monsters. Also in 2020, something big visited Wright and Stigar’s camera and tore off part of the metal contraption that had been baited with a filleted carcass of a sockeye. It was the typical fisherman story—the camera had run out of battery shortly before the creature struck. 

An Iliamna Lake freshwater seal investigates Mark Stigar and Bruce Wright's underwater camera. Photo courtesy of Mark Stigar

Stigar and Wright plan to be back at it in the summer of 2021. They’re working on improving their camera system and are adding a drone to their kit. Wright’s best guess is that the “monster” is a giant pike; Stigar believes it’s most likely to be a sleeper shark or something similar. It’s evening entertainment, Stigar said, even if nothing ever comes of it.

“There’s something out there,” Stigar added. “I’m not so arrogant to think we know everything that’s out there.”

A view of Lake Iliamna's shoreline from a small plane. Photo courtesy of Chris Miller

Pride of Bristol Bay is a free column written by Bjorn Dihle and provided by its namesake, a fisherman direct seafood marketer that specializes in delivering the highest quality of sustainably caught wild salmon from Bristol Bay to your doorstep.