Alaskan King Crab
Paralithodes camtschaticus
Alaskan king crabs are named after the bright red color they turn once cooked. Similar to the majority of crab species, they have a large, hefty shell that is sometimes referred to as a carapace. Huge, sharp spines on their exoskeleton cover every inch of their bodies and act as a defense against predators.
SPECIES IN DETAIL
Alaskan King Crab
Paralithodes camtschaticus
CONSERVATION STATUS: Least concern-protected
CLIMATE CHANGE:
At the Aquarium
Not currently on display.
Geographic Distribution
Alaskan king crabs can be found in North American seas, the Bering Sea and Aleutian Islands, along the Gulf of Alaska coast, and as far south as British Columbia, Canada.
Bristol Bay, the Pribilof Islands, Norton Sound, and the Western Aleutian Islands host the four king crab stocks.
Habitat
Juveniles, who are under 2 years of age, live in shallow waters in complex habitats such as shell hash, cobble, algae, and among bryozoans (microscopic aquatic invertebrates that live in colonies) to avoid predation.
Older juveniles form pods who travel together. They stay busy mounding up (creating protective mud mounds) during the day and feeding at night.
Mature crabs move into deeper water that is typically less than 600 feet along the continental shelf to feed. The mature females return to shallow waters to hatch their eggs. During their lifespan, the crabs settle between 200 and 600 feet deep.
Physical Characteristics
The crabs’ colors range from brownish-blue to burgundy-red.
Alaskan king crabs have “tails,” or abdomens, which are fan-shaped and tucked under the back of the shell. Additionally, they have five pairs of legs. The first pair bears their claws or pincers; on adults, the right claw is typically the largest. The following three pairs of claws are used for walking, and the little fifth pair is typically tucked under the back of their carapace. Their shells are covered with a spiny exoskeleton that provides protection from potential predators.
Size
Adult Alaskan king crabs can be very large with leg spans reaching nearly 1.8 m (5 feet) and weights over 9 kg (20 pounds)!
Diet
The majority of food eaten by Alaskan king crabs is first crushed with their claws and then devoured. Algae, tiny worms, tiny clams, and other tiny creatures are consumed by smaller crabs. A far wider variety of foods such as worms, clams, mussels, barnacles, crabs, fish, sea stars, sand dollars, and brittle stars are consumed by larger crabs.
Reproduction
Alaskan king crabs reproduce through internal fertilization. The females brood the fertilized eggs under their belly for up to a year. They prefer cold water as they focus on feeding themselves and caring for their eggs, so during the summer months they stay in quite deep waters up to 600 feet deep. They move to shallower waters in the late winter where their eggs hatch in spring, and the sexually mature animals will molt and mate once more.
Behavior
King crabs are solitary animals outside of the breeding season. They have been seen to band together, nevertheless, in the presence of powerful predators. They will form a pod by stacking on top of one another to make themselves appear bigger and more dangerous. These pods, which may reach heights of several feet, are filled with stacks of hundreds of crabs.
Alaskan king crab adults make annual migrations from the close shore to the offshore (or shallow to deep) and return. They arrive in shallow water in the late winter, and the female’s eggs hatch in the spring. Before beginning their offshore feeding journey to deeper seas, mature females and some adult males molt and mate. Off the mating-molting grounds, adult crabs frequently separate by sex. Even though their habitats and depth ranges may overlap, red, blue, and golden king crabs are rarely observed living side by side. In the Kodiak, AK region, adult male red king crabs have been observed to travel as quickly as one mile per day and to migrate up to 100 miles round-trip annually!
Adaptation
The king crab’s shell is actually its fixed, external skeleton which can not extend. Crabs must molt (or shed) this exoskeleton on a regular basis in order to grow larger. An individual starts constructing a new, larger exoskeleton inside the old one before molting. The outer shell splits open when the new shell becomes too large to be contained, and the new exoskeleton begins to harden. The new exoskeleton may be fragile during this process and for a while the crabs face increased vulnerability to predators.
Their two claws perform different tasks. The larger, more powerful claw is used for smashing prey, while the smaller, more delicate claw is used to handle food items.
Conservation
Currently, the Alaska Department of Fish and Game, rates the status of red king as healthy. However, most Alaskan red king crab stocks are depleted, and fishing is restricted or suspended. There are several local stocks with strict quotas elsewhere in the state, and SE Alaska stocks are regarded as being large enough to fish.
King crab populations fluctuate seasonally as a result of environmental conditions. To account for these population variations, human harvest needs to be strictly controlled and anticipate population changes. These two key factors are crucial for managing the fisheries to prevent overharvesting. Overharvesting has occurred in the past and must be guarded against.
Special Notes
Red king crabs have many predators who will consume them. Fish (Pacific cod, sculpins, halibut, yellowfin sole), octopuses, king crabs themselves who are capable of cannibalism, and sea otters prey upon them. Numerous new species of nemertean worms have been discovered to consume king crab embryos.
Human harvest uses the red king crabs generally for commercial purposes because of their large size.
SPECIES IN DETAIL | Print full entry
Alaskan King Crab
Paralithodes camtschaticus
CONSERVATION STATUS: Least concern-protected
CLIMATE CHANGE:
Not currently on display.
Alaskan king crabs can be found in North American seas, the Bering Sea and Aleutian Islands, along the Gulf of Alaska coast, and as far south as British Columbia, Canada.
Bristol Bay, the Pribilof Islands, Norton Sound, and the Western Aleutian Islands host the four king crab stocks.
Juveniles, who are under 2 years of age, live in shallow waters in complex habitats such as shell hash, cobble, algae, and among bryozoans (microscopic aquatic invertebrates that live in colonies) to avoid predation.
Older juveniles form pods who travel together. They stay busy mounding up (creating protective mud mounds) during the day and feeding at night.
Mature crabs move into deeper water that is typically less than 600 feet along the continental shelf to feed. The mature females return to shallow waters to hatch their eggs. During their lifespan, the crabs settle between 200 and 600 feet deep.
The crabs’ colors range from brownish-blue to burgundy-red.
Alaskan king crabs have “tails,” or abdomens, which are fan-shaped and tucked under the back of the shell. Additionally, they have five pairs of legs. The first pair bears their claws or pincers; on adults, the right claw is typically the largest. The following three pairs of claws are used for walking, and the little fifth pair is typically tucked under the back of their carapace. Their shells are covered with a spiny exoskeleton that provides protection from potential predators.
Adult Alaskan king crabs can be very large with leg spans reaching nearly 1.8 m (5 feet) and weights over 9 kg (20 pounds)!
The majority of food eaten by Alaskan king crabs is first crushed with their claws and then devoured. Algae, tiny worms, tiny clams, and other tiny creatures are consumed by smaller crabs. A far wider variety of foods such as worms, clams, mussels, barnacles, crabs, fish, sea stars, sand dollars, and brittle stars are consumed by larger crabs.
Alaskan king crabs reproduce through internal fertilization. The females brood the fertilized eggs under their belly for up to a year. They prefer cold water as they focus on feeding themselves and caring for their eggs, so during the summer months they stay in quite deep waters up to 600 feet deep. They move to shallower waters in the late winter where their eggs hatch in spring, and the sexually mature animals will molt and mate once more.
King crabs are solitary animals outside of the breeding season. They have been seen to band together, nevertheless, in the presence of powerful predators. They will form a pod by stacking on top of one another to make themselves appear bigger and more dangerous. These pods, which may reach heights of several feet, are filled with stacks of hundreds of crabs.
Alaskan king crab adults make annual migrations from the close shore to the offshore (or shallow to deep) and return. They arrive in shallow water in the late winter, and the female’s eggs hatch in the spring. Before beginning their offshore feeding journey to deeper seas, mature females and some adult males molt and mate. Off the mating-molting grounds, adult crabs frequently separate by sex. Even though their habitats and depth ranges may overlap, red, blue, and golden king crabs are rarely observed living side by side. In the Kodiak, AK region, adult male red king crabs have been observed to travel as quickly as one mile per day and to migrate up to 100 miles round-trip annually!
The king crab’s shell is actually its fixed, external skeleton which can not extend. Crabs must molt (or shed) this exoskeleton on a regular basis in order to grow larger. An individual starts constructing a new, larger exoskeleton inside the old one before molting. The outer shell splits open when the new shell becomes too large to be contained, and the new exoskeleton begins to harden. The new exoskeleton may be fragile during this process and for a while the crabs face increased vulnerability to predators.
Their two claws perform different tasks. The larger, more powerful claw is used for smashing prey, while the smaller, more delicate claw is used to handle food items.
Currently, the Alaska Department of Fish and Game, rates the status of red king as healthy. However, most Alaskan red king crab stocks are depleted, and fishing is restricted or suspended. There are several local stocks with strict quotas elsewhere in the state, and SE Alaska stocks are regarded as being large enough to fish.
King crab populations fluctuate seasonally as a result of environmental conditions. To account for these population variations, human harvest needs to be strictly controlled and anticipate population changes. These two key factors are crucial for managing the fisheries to prevent overharvesting. Overharvesting has occurred in the past and must be guarded against.
Red king crabs have many predators who will consume them. Fish (Pacific cod, sculpins, halibut, yellowfin sole), octopuses, king crabs themselves who are capable of cannibalism, and sea otters prey upon them. Numerous new species of nemertean worms have been discovered to consume king crab embryos.
Human harvest uses the red king crabs generally for commercial purposes because of their large size.