ANCHORAGE, Alaska — Let the chunk-off begin.

Voting starts Wednesday in the annual Fat Bear Week contest at Alaska’s Katmai National Park and Preserve, with viewers picking their favorite among a dozen brown bears fattened up to survive the winter.

The contest, which is in its 10th year, celebrates the resiliency of the 2,200 brown bears that live in the preserve on the Alaska Peninsula, which extends from the state’s southwest corner toward the Aleutian Islands. The animals gorge on the abundant sockeye salmon that return to the Brooks River, sometimes chomping the fish in midair as they try to hurdle a small waterfall and make their way upstream to spawn.

A bear’s death delays the contest

Organizers introduced this year’s contestants on Tuesday – a day late – because one anticipated participant, a female known as Bear 402, was killed by a male bear during a fight on Monday. Cameras set up in the park to livestream footage of the bears all summer captured the killing, as they also captured a male bear killing a cub that slipped over the waterfall in late July.

“National parks like Katmai protect not only the wonders of nature, but also the harsh realities,” park spokesperson Matt Johnson said in a statement. “Each bear seen on the webcams is competing with others to survive.”

The nonprofit explore.org, which streams the uncensored bear cameras and helps organize Fat Bear Week, on Tuesday hosted a live conversation about the death. Katmai National Park ranger Sarah Bruce said it wasn’t known why the bears started fighting.

“We love to celebrate the success of bears with full stomachs and ample body fat, but the ferocity of bears is real,” said Mike Fitz, explore.org’s resident naturalist. “The risks that they face are real. Their lives can be hard, and their deaths can be painful.”

Packing on the pounds for survival

The bracket this year features 12 bears, with eight facing off against each other in the first round and four receiving byes to the second round. They’ve all been packing on the pounds all summer.

Adult male brown bears typically weigh 600 to 900 pounds (about 270 to 410 kilograms) in mid-summer. By the time they are ready to hibernate after feasting on migrating and spawning salmon – each eats as many as 30 fish per day – large males can weigh well over 1,000 pounds (454 kilograms). Females are about one-third smaller.

A taste for seagulls and a bear named after a jumbo jet

Bear 909 Jr., who last week won the Fat Bear Junior competition for the second time, will face Bear 519, a young female in the first round. The winner will face the defending champion, Grazer, described as one of the most formidable bears on the river.

Another first-round match pits Bear 903, an 8-year-old male who was given the nickname Gully after he developed a taste for seagulls, against Bear 909, the mother of Bear 909 Jr. The winner faces a two-time champion, a bear so large he was given the number of the equally massive airplane, Bear 747.

One of the biggest bears ate 42 salmon

In the other half of the bracket, the first-round match has Bear 856, an older male and one of the most recognizable bears on the river because of his large body, challenging a newcomer, Bear 504, a mother bear raising her second known litter. The winner will face perhaps the largest bear on the river, 32 Chunk, a 20-year-old male who once devoured 42 salmon in 10 hours. He’s estimated to weigh more than 1,200 pounds.

The last first-round match has Bear 151, a once-playful young bear nicknamed Walker now showing more dominance, versus Bear 901, a solo female who has returned to the river after her first litter did not survive. The winner will face Bear 164, called Bucky Dent because of an indentation in his forehead.

Voting in this year’s tournament-style bracket is open through Oct. 8.

More than 1.3 million votes were cast last year.

Video in player above is from previous coverage.