Red King Crab Facts and Identification

A red king crab

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They are the biggest and most sought-after shellfish in Alaska. What are they? Red king crab. Red king crab (Paralithodes camtschaticus) is one of several king crab species. They entice fishers and seafood consumers with their snow-white (edged by red), flavorful meat. If you're a fan of reality TV, you might be familiar with red king crab, as they are one of two species (along with snow, or opilio crab) fished on "Deadliest Catch."

What Do King Crabs Look Like?

As you'd probably guess from the name, red king crab have a reddish carapace that can vary from brownish to dark red or burgundy. They are covered in sharp spines. These are the largest crab in Alaska. Since they don't expend as much energy in reproduction, males can grow much larger than females. Females can weigh up to about 10.5 pounds. The largest male on record weighed 24 pounds and had a leg span of about 5 feet. 

These crabs have three pairs of legs used for walking and two claws. One claw is larger than the other and is used for crushing prey. 

While it may not be apparent, these crabs are descended from hermit crab ancestors. Like hermit crabs, a red king crab's back end is twisted to one side (more drastically in hermit crabs, so they can fit into the gastropod shells that provide their shelter), they have one claw larger than the other, and their walking legs all point backward. 

How Do You Distinguish Male King Crabs from Females?

How do you tell males from females? There is one easy way: To keep crab populations healthy, only male red king crabs can be harvested, so if you're eating a king crab, it is most likely a male. In addition to size differences, males can be distinguished from females by the flap on their underside, which is triangular in males and rounded in females (this flap is larger in females because it is used to carry eggs). 


  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Crustacea
  • Class: Malacostraca
  • Order: Decapoda
  • Family: Lithodidae
  • Genus: Paralithodes
  • Species: P. camtschaticus

Where Do Red King Crabs Live?

Red king crabs are a cold water species native to the Pacific Ocean, although they were also intentionally introduced into the Barents Sea 200. In the Pacific Ocean, they are found from Alaska to British Columbia and Russia to Japan. They are usually found in waters less than 650 feet deep. 

What Do Red King Crabs Eat?

Red king crabs feed on a variety of organisms, including algae, worms, bivalves (e.g., clams and mussels), barnacles, fish, echinoderms (sea stars, brittle stars, sand dollars) and even other crabs. 

How Do Red King Crabs Reproduce?

Red king crabs reproduce sexually, with internal fertilization. Mating occurs in shallow water. Depending upon their size, females can produce between 50,000 and 500,000 eggs. During mating, males grasp the female and fertilize the eggs, which she carries on her abdominal flap for 11-12 months before they hatch.

Once they hatch, the red king crab larvae look similar to shrimp. They can swim, but are largely at the mercy of tides and currents. They go through several molts over 2-3 months and then metamorphose into a glaucothoe, which settles to the ocean bottom and metamorphoses into a crab that spends the rest of its life on the ocean bottom. As they grow, red king crabs molt, which means they lose their old shell and form a new one. During its first year, a red king crab will molt up to five times. These crabs are sexually mature at about 7 years old. These crabs are estimated to live up to 20-30 years. 

Conservation, Human Uses, and the Famous Crab Fishery

After sockeye salmon, red king crab is the most valuable fishery in Alaska. The crab meat is eaten as crab legs (e.g., with drawn butter), sushi, or in a variety of other dishes. 

Red king crabs are caught in heavy metal pots in a fishery that is famous for its dangerous seas and weather. To read more about red king crab fishing, click here. 

"Deadliest Catch"—a crustacean lover's favorite reality series—tells the harrowing at-sea adventures of the captains and crew on 6 boats. But there were 63 boats in the Bristol Bay red king crab fishery in 2014. These boats caught the 9 million pound quota of crab in about four weeks. Much of that crab is shipped to Japan. 

As for the U.S., it is likely the red king crab you eat isn't caught by the fishermen on the "Deadliest Catch" boats. According to, in 2013, 80 percent of the red king crab sold in the U.S. was caught in Russia. 

Threats to Red King Crab Populations

Although catches of red king crab are steady at the moment, recent reports show they are vulnerable to ocean acidification, a lowering of the ocean's pH, which makes it difficult for crabs and other organisms to form their exoskeleton. 


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Your Citation
Kennedy, Jennifer. "Red King Crab Facts and Identification." ThoughtCo, Apr. 5, 2023, Kennedy, Jennifer. (2023, April 5). Red King Crab Facts and Identification. Retrieved from Kennedy, Jennifer. "Red King Crab Facts and Identification." ThoughtCo. (accessed May 28, 2023).