The red king crab that wasn't red appeared in Nome on the Fourth of July.

Biologist Scott Kent was getting ready to go salmon fishing in the Norton Sound when he ran into commercial crab fisherman Frank MacFarland, who was delivering his latest catch.

"I got one of those blue ones," MacFarland told him. The fisherman held up the specimen so Kent, assistant area management biologist for the state Department of Fish and Game in Nome, could see.

The crab's shell was a deep periwinkle, likely the result of a naturally occurring genetic mutation, Kent said. The rare discovery thrilled Norton Sound fishery managers and biologists in the Northwest Alaska city.

Recognizing the crab's distinctiveness, MacFarland delivered it to the Norton Sound Seafood Center and told plant managers not to sell it. For now, it's scuttling around the center's 350-gallon live tank, where assistant plant manager Justin Noffsker is caring for it.

"It's kind of the color of a forget-me-not," said Noffsker, referring to the vivid blue of the Alaska state flower. Red king crabs are normally, you know, red.

Noffsker said he's never seen anything like this bluish variety. In his 11 years with the Alaska Department of Fish and Game, Kent had never seen a blue red king crab either -- only in photographs from the mid-1980s.

In September, during a pot survey in Cape Nome, Kent saw his first white red king crab, another rare coloration believed to be caused by a genetic mutation. He has also recently seen piebald crabs, spotted with irregular patches of white. Another had a red carapace but yellow legs.

All the variations are considered to be the kind of "normal, random, very rare" mutations that occur within animal populations, Kent said. The environment and the crab's diet could play a role, he said, but he doubts it.

MacFarland's crab "looked like a very healthy crab to me," Kent said.

Reported sightings of the irregularly colored crabs have increased alongside the growth of Norton Sound research, Kent said, including more rigorous sampling of crabs caught in the region. That includes a spring tagging study and a summer observer program.

Fishermen too are doing a better job at pointing out unusual animals, Kent said.

It's certainly not the first recent sighting of a blue red king crab. Or lavender, depending on the eye of the beholder. In January, wholesalers in Hokkaido, Japan, found one in a Russian shipment.

"'Mutant' lavender king crab found," exclaimed a New York Post headline.

MacFarland couldn't be reached for an interview but Noffsker said the fisherman was interested in eventually having the animal mounted for display by a taxidermist.

For the area biologists, these types of discoveries are what the job is all about.