S
Species Profile

Snow Crab

Chionoecetes opilio

Built for the seafloor's deep freeze
Kondratuk Aleksei/Shutterstock.com

Snow Crab Distribution

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This map shows coastal regions where Snow Crab are found.

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Snow crab on the sea bed

At a Glance

Wild Species
Also Known As Opilio, Opilio crab, Crabe des neiges, Cangrejo de las nieves, Zuwaigani (zuwai-gani)
Diet Omnivore
Activity Cathemeral
Lifespan 15 years
Weight 1.8 lbs
Status Least Concern
Did You Know?

Max male carapace width is commonly reported up to ~16.5 cm; females are smaller (often <10 cm).

Scientific Classification

A cold-water marine crab (a ‘tanner crab’) widely harvested in the North Atlantic and North Pacific and commonly sold as ‘snow crab’ in seafood markets.

Kingdom
Animalia
Phylum
Arthropoda
Class
Malacostraca
Order
Decapoda
Family
Oregoniidae
Genus
Chionoecetes
Species
Chionoecetes opilio

Distinguishing Features

  • Long, slender walking legs relative to body size (the ‘snow crab’ look)
  • Carapace with a generally rounded-triangular outline; males have notably larger claws
  • Cold-water distribution; typically encountered/harvested on the seafloor rather than in shallow intertidal zones
  • Commonly sold as clusters of leg sections; can be confused with other Chionoecetes species in commerce

Physical Measurements

Males and females differ in size

Length
♂ 2 in (2 in – 3 in)
♀ 3 in (2 in – 4 in)
Weight
♂ 2 lbs (1 lbs – 3 lbs)
♀ 1 lbs (0 lbs – 1 lbs)
Top Speed
0 mph
walking

Appearance

Primary Colors
Secondary Colors
Skin Type Calcified chitinous exoskeleton with fine spines and setae; hard carapace, long slender ambulatory legs.
Distinctive Features
  • Adult male carapace width commonly ~9-14 cm; reported maximum ~16.5 cm (Chionoecetes opilio).
  • Long, slender legs; overall span across extended legs can approach ~1 m in large males.
  • Carapace subtriangular/rounded with a bifid rostrum; anterolateral margin typically bears 4 spines (key ID feature).
  • Legs and carapace often lightly setose (hairy), but generally less robust than C. bairdi ('Tanner crab').
  • Cold-water benthic species: frequently encountered on soft bottoms from ~20 to >1000 m depth; commonly associated with ~−1 to 5 °C bottom temperatures.
  • Commercially harvested 'snow crab'; note market confusion with C. bairdi, which is typically darker, more robust, and usually has 5 anterolateral spines.

Sexual Dimorphism

Males grow larger with proportionally longer legs and enlarged chelae, while females remain smaller with a broader, rounded abdominal apron for egg carrying. Mature males often dominate the largest size classes in fisheries.

♂
  • Typically much larger: carapace width up to ~16.5 cm reported.
  • Longer, more slender walking legs; greater overall leg span.
  • Chelae (claws) proportionally larger, especially in mature males.
  • Narrow, triangular abdominal flap (apron).
♀
  • Smaller maximum size (typically up to about 9 cm carapace width).
  • Broader, rounded abdominal apron adapted for brooding eggs.
  • Relatively shorter legs and smaller chelae than males at similar ages.
  • Egg masses carried on pleopods beneath abdomen (seasonal), not visible dorsally.

Did You Know?

Max male carapace width is commonly reported up to ~16.5 cm; females are smaller (often <10 cm).

Males can reach ~1 m leg span, giving "snow crab clusters" their long, delicate look.

After the terminal molt, males stop molting for life-size is "locked in," while energy shifts toward mating and survival.

Females carry fertilized eggs on their abdomen for roughly 1-2 years (regional variation), brooding them through multiple seasons.

A single female can carry on the order of tens to >100 thousand eggs per brood (fecundity increases strongly with size).

They thrive near freezing: they commonly occupy seafloors around about −1 to 5 °C and can remain active in icy conditions.

Seafood markets sometimes label multiple Chionoecetes species as "snow crab"; true C. opilio is often confused with the larger, spikier Tanner crab C. bairdi.

Unique Adaptations

  • Cold-water physiology: tolerates near-freezing bottom temperatures with metabolic and osmoregulatory adjustments that keep muscles and nerves functioning in icy seawater.
  • Long, slender walking legs: increases stride efficiency over soft sediments and helps cover large areas while searching for food or mates on the seafloor.
  • Cryptic coloration: mottled tan-to-brown carapace blends with mud/sand bottoms, reducing detection by groundfish predators.
  • Spination & tough exoskeleton (post-molt): carapace and leg spines deter predators; hardness increases substantially after molting as minerals are redeposited.
  • Egg brooding on pleopods: females aerate and clean egg masses with abdominal appendages, improving oxygenation and reducing fouling over long incubation times.

Interesting Behaviors

  • Benthic roaming & seasonal shifts: juveniles and adults move along the seafloor, often shifting depth with season and temperature; many populations concentrate on productive shelf grounds for feeding.
  • Mating tied to female molt: males guard and mate with females around the time females molt to maturity, when the shell is soft enough for successful copulation and later egg extrusion.
  • Terminal-molt strategy (males): adult males stop growing after a final molt; afterward they invest in mate searching, competition, and long-distance walking rather than additional growth.
  • Opportunistic feeding: primarily a scavenger/predator mix-takes polychaete worms, bivalves, small crustaceans, echinoderms, and carrion depending on local availability.
  • Aggregation: can form dense local concentrations ("patches") on suitable sediments, which is a key reason pot fisheries can be highly efficient in the right grounds.
  • Predation & cannibalism: vulnerable juveniles may be eaten by fish and larger crabs; cannibalism can occur, especially where densities are high and shelter is limited.

Cultural Significance

Chionoecetes opilio supports cold-water pot fisheries and coastal jobs in Atlantic Canada (Gulf of St. Lawrence, Newfoundland and Labrador) and parts of the North Pacific. Sold as "snow crab" (name also used for other Chionoecetes like C. bairdi); clear labels matter for tracking and fish stock management.

Myths & Legends

Name origin (historical/naming): the species epithet opilio is Latin for "shepherd," a traditional natural-history naming that evokes a roaming, long-legged animal moving across open ground-apt for this crab's wide seafloor wanderings.

Snow crab (Chionoecetes opilio) became a common food name in North America, showing the crab's cold habitat and white meat. The name is still used even when other Chionoecetes species are sold instead.

For snow crab (Chionoecetes opilio) in the North Atlantic, Atlantic Canadian communities treat snow crab season like a yearly spring event: opening dates, dockside landings, and first cooked meals are local traditions and community celebrations.

Conservation Status

LC Least Concern

Widespread and abundant in the wild.

Population Unknown

Protected Under

  • Magnuson-Stevens Fishery Conservation and Management Act (United States)
  • Bering Sea/Aleutian Islands King and Tanner Crabs Fishery Management Plan (United States)
  • Fisheries Act (Canada)
  • Regional fishery management measures (e.g., TACs/closures/size limits) in North Atlantic and North Pacific jurisdictions

Life Cycle

Birth 75000 larvas
Lifespan 15 years

Lifespan

In the Wild
10–20 years
In Captivity
1–6 years

Reproduction

Mating System Polygynandry
Social Structure Transient
Breeding Pattern Transient
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Males locate and guard pre-molt females, mating soon after the female's pubertal/terminal molt by transferring spermatophores for internal fertilization; females can store sperm and later extrude and brood eggs on pleopods without male or helper care.

Behavior & Ecology

Social Aggregation
Activity Cathemeral
Diet Omnivore Bivalve clams and polychaete worms (dominant benthic prey items in gut-content studies of Chionoecetes opilio).

Temperament

Generally non-territorial benthic forager; extensive home-range overlap where habitat and food are suitable.
Males can be aggressive near receptive females; agonism includes chela displays and pushing (Sainte-Marie 1993).
Prolonged pre-copulatory mate guarding occurs; large males preferentially guard pre-molt females (Sainte-Marie 1993).
Strong size/sex spatial segregation is common; patterns vary by region, temperature, and depth structure.
Longevity often modeled at ~12-16 years in NW Atlantic from molt/growth dynamics (Alunno-Bruscia & Sainte-Marie 1998).

Communication

None known; no species-specific sound production reported for Chionoecetes opilio.
Chemical cues: pre-molt females emit pheromones; males locate and guard females Sainte-Marie 1993
Contact chemoreception via antennules and walking legs during mate assessment and recognition.
Tactile signaling: grasping/holding in mate guarding; chela and leg contact during contests.
Visual/positional displays at close range (chela spread, body elevation) during agonistic interactions.

Habitat

Seabed/Benthic Deep Sea Coastal Open Ocean
Biomes:
Terrain:
Coastal Muddy Sandy
Elevation: -47244 in

Ecological Role

Benthic mesopredator and scavenger in cold-water shelf ecosystems (North Atlantic & North Pacific), linking benthic invertebrate production to higher trophic levels.

Regulates benthic invertebrate communities through predation (notably polychaetes and bivalves) Scavenges carrion, accelerating organic-matter recycling and nutrient turnover Bioturbation and sediment reworking while foraging/excavating Trophic transfer: important prey/energy source for demersal fishes and marine mammals in parts of its range

Diet Details

Main Prey:
Polychaete worms Bivalve clams Crustaceans Echinoderms Gastropods Fish carrion/offal
Other Foods:
Macroalgae fragments Benthic microalgae and biofilm Detrital organic matter

Human Interaction

Domestication Status

Wild

Snow crab (Chionoecetes opilio) is not domesticated. People catch wild snow crab in North Atlantic and North Pacific fisheries. Management uses quotas, size and sex rules, seasons, and gear limits. Crabs may be kept alive short-term in tanks before processing, but there is no routine captive breeding or pet trade.

Danger Level

Low
  • Pinch injuries from claws/spines during live handling (typically minor but can break skin).
  • Food allergy risk (crustacean shellfish are a major allergen).
  • Foodborne illness risk if temperature control is poor (notably Vibrio spp. are a concern for seafood generally; risk management depends on handling and cooking).
  • Occupational hazards in fisheries (gear handling, cold exposure, vessel risk) are significant, though not from the crab's intrinsic behavior.

As a Pet

Not Suitable as Pet

Legality: Legality varies by place. Snow crab (Chionoecetes opilio) is often not banned as a pet, but collecting, keeping, importing, or moving live crabs can need permits, follow seasons/size rules, and often forbid females or undersized crabs.

Care Level: Expert Only

Purchase Cost: $20 - $200
Lifetime Cost: $2,000 - $15,000

Economic Value

Uses:
Commercial capture fisheries Seafood processing and export Employment and coastal community income Subsistence/food provisioning in some regions Fisheries research, monitoring, and management
Products:
  • cooked/sectioned snow crab legs and clusters
  • whole cooked crab
  • picked crab meat (fresh/frozen/canned)
  • shell by-products (chitin/chitosan potential; fertilizer/soil amendments in some waste streams)

Relationships

Predators 8

Pacific cod Gadus macrocephalus
Atlantic cod
Atlantic cod Gadus morhua
Greenland halibut Reinhardtius hippoglossoides
Pacific halibut Hippoglossus stenolepis
Thorny skate Amblyraja radiata
Giant Pacific octopus Enteroctopus dofleini
Northern sea otter Enhydra lutris kenyoni
Atlantic wolffish Anarhichas lupus

Related Species 8

Tanner crab Chionoecetes bairdi Shared Genus
Triangle tanner crab Chionoecetes angulatus Shared Genus
Grooved tanner crab Chionoecetes tanneri Shared Genus
Red snow crab Chionoecetes japonicus Shared Genus
Rathbun's tanner crab Chionoecetes rathbuni Shared Genus
Great spider crab Hyas araneus Shared Family
Toad crab Hyas coarctatus Shared Family
Graceful decorator crab Oregonia gracilis Shared Family

Ecological Equivalents 5

Animals that fill a similar ecological role in their ecosystem

Tanner crab Chionoecetes bairdi Cold-water, bottom-dwelling tanner crab that consumes benthic animals and scavenges; males undergo a final molt. Occurs at similar depths (~50–400 m) in the North Pacific and is fished similarly.
Red king crab Paralithodes camtschaticus A large, cold-water benthic king crab that shares subarctic continental-shelf habitats and is caught in pots alongside snow crab. Both live on cold seabeds and feed on many benthic animals (bivalves, worms, starfish, crustaceans) and carrion.
Blue king crab Paralithodes platypus Co-occurs in subarctic North Pacific shelf ecosystems and uses similar benthic habitats. Overlaps in prey base (bivalves, worms, echinoderms) and in predator guilds (cod, halibut, octopus).
Southern Tanner crab Chionoecetes australis Ecological analogue in the Southern Ocean: a cold-water, deep benthic tanner crab that occupies soft-bottom habitats and feeds on benthic invertebrates and scavenged material, fulfilling a similar ecological role to snow crab despite occurring in a different ocean basin.
Jonah crab
Jonah crab Cancer borealis Northwest Atlantic benthic commercial crab that overlaps with snow crab fisheries and markets in the region and occupies a similar functional role as a bottom-dwelling omnivore and predator on mollusks and other invertebrates, though it generally inhabits somewhat warmer, shallower waters than the coldest, deepest concentrations of snow crab.

The Snow Crab, also known as the Opie, is native to the northern parts of the Atlantic and Pacific Oceans, with high populations off the Alaskan coast. These crabs are an essential part of the commercial fishing industry, supplying countless seafood restaurants. Although these crustaceans have enjoyed healthy levels for fishing, ocean and climate change are threats to these creatures that may impact the price in the event of a shortage.

5 Snow Crab Facts

  • Named for the color of its meat after it has been cooked
  • Have four pairs of legs and one pair of claws
  • Spend most of their lives on seafloors
  • Live in groups known as clusters
  • Eat mostly brittle creatures that they crush with their claws

Classification and Scientific Name

The Snow Crab’s scientific name is Chionoecetes opilio. Sometimes people refer to these crabs as opies or opilio crabs. These crabs are part of the Decapoda order, which includes 15,000 distinct species. Most of the species in this order are considered scavengers. Their family is Oregoniidae, encompassing several similar crab species.

Appearance

Snow Crabs have carapaces or brown or red shells, with yellow or white shading on the underside. This shading helps provide cover in the deep waters where these crabs live. The four pairs of legs help these crustaceans move effortlessly through the Alaskan and the North Atlantic ocean bottoms.

Snow crab on a white background

Snow crabs have four pairs of legs.

Distribution, Population, and Habitat

In 2020, the National Oceanic and Atmospheric Administration (NOAA) estimated the commercial landings of Snow Crab in Alaska to number approximately 56 million pounds. A dramatic shortage of snow crabs was reported in the Bering Sea (Pacific) between 2018 and 2021, leading to the closure of the Alaska snow crab fishery in 2022 and 2023. As of 2025, NOAA does not consider the species overfished, but the stock is still rebuilding. Migration patterns for these crabs are not as well-known as those of other species. The most significant population shifts have been observed in the Bering Sea, with numbers growing consistently.

Ocean currents help play a role in their distribution. These crabs live at varying depths from 66 to 265 feet. They can be found as far north as Greenland and as far south as the Gulf of St. Lawrence in the Atlantic Ocean. The habitat ranges from Siberia and Alaska to as far south as Korea, in the Pacific, with clusters having been found in all these locations.

Predators and Prey

Snow Crabs are often prey for other species and have been severely impacted by climate change, particularly marine heatwaves. According to NOAA, they are not currently subject to overfishing, but the population is still rebuilding. For example, their meat is in high demand among people who enjoy seafood. With this demand comes the potential for overfishing, with some numbers of smaller Snow Crabs having dwindled. Warming ocean temperatures threaten snow crabs, as recent marine heatwaves have been linked to mass die-offs and population collapse, primarily due to ecosystem changes and food scarcity rather than a strict temperature threshold.

What eats snow crabs?

Humans are one of their most significant predators. Halibut also regularly eat these crustaceans, and larger Snow Crabs have been known to eat juveniles because their size makes them easy prey. Other predators include seals and squid, as well as the Alaskan King Crab.

Although Snow crabs have predators, they have shells that make it difficult for some predators to kill them. Their claws also serve as effective deterrents against predation.

What do snow crabs eat?

These crabs eat a variety of species that include smaller crabs, shrimp, and plankton. They are also capable of scavenging for food when prey is minimal.

Reproduction and Lifespan

Snow Crabs may live as long as 20 years. Female crabs may carry up to 100,000 eggs, provided there are adequate food supplies. The larvae hatch in the spring and go through several growth periods known as molting. These crabs molt for the last time at four years or later, which marks sexual maturity. Females usually reach this stage sooner than males.

Snow Crab in Fishing and Cooking

A plate filled with steamed snow crab legs served with butter and lemon

A plate of cooked snow crab legs, which are so named for their snowy white meat.

Snow Crab is a commercial seafood, attractive to many commercial fishing companies because of the price they get. Live traps that reach the seafloor level are the primary method of catching this crab. The Alaska (Bering Sea) snow crab season typically runs from October to May, while Atlantic Canadian seasons often start in April. In 2020, about 56 million pounds of snow crab were harvested in Alaska.

This type of crab has a firm texture, with a flavor described as salty and sweet. Many serve the meat shredded, similar to how corned beef is served.

Snow Crab is a favorite species worldwide, with the United States and Japan among the largest consumers. Denmark is a major re-export hub, and South Korea is also a significant market. It has 90 calories and 18.5 grams of protein per ounce, making it a healthy food choice for use in a variety of recipes.

View all 391 animals that start with S

Sources

  1. A Classification of Living and Fossil Genera of Decapod Crustaceans / Accessed April 6, 2022
  2. Animal Diversity / Accessed April 6, 2022
  3. Government of Canada / Accessed April 6, 2022
  4. NOAA Fisheries / Accessed April 6, 2022
  5. This Fish / Accessed April 6, 2022
  6. Quality Seafood Delivery / Accessed April 6, 2022
  7. Tradex Foods / Accessed April 6, 2022
  8. Linked In / Accessed April 6, 2022
A-Z Animals Staff

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A-Z Animals Staff

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Snow Crab FAQs (Frequently Asked Questions)

Snow crab has a sweet and salty taste that is milder than most other crab species.