Alaska King Crab

The family Lithodidae, known as the stone or king crabs, has
16 genera and 95 known species. Four species are commercially fished in Alaskan
waters. These are the red king crabs (Paralithodes camtschaticus), the
blue king crabs (Paralithodes platypus), the golden king crabs (Lithodes
aequispinus), and the scarlet king crabs (Lithodes couesi). Of
these, red king crabs are the most abundant and extensively studied species. Scarlet
king crabs are much smaller than the other three species, and because they live
in very deep water, researchers know little about their life cycle. Since scarlet
crabs are smaller than red, blue and golden king crabs, they are not commercially
significant.

[image error]Red King Crab

 All four species have
different but overlapping distributions throughout the Gulf of Alaska, Bering
Sea, and the Aleutian Islands. Red king crabs range from British Columbia to
Japan and north to the Bering Sea. They are most abundant in Bristol Bay and
the Kodiak Archipelago. Red king crabs exist from the intertidal zone to 600
ft. (183 m) or deeper.

King crabs receive their common names from the color of
their carapaces. All king crabs are decapods, meaning they have ten legs. Unlike
brachyuran crabs, which are considered “true” crabs, king crabs are not
symmetrical but have an asymmetrical abdomen, asymmetrical first pair of
walking legs, and modified fifth pair of walking legs. Biologists think king
crabs are more closely related to hermit crabs than they are to brachyuran
crabs such as Dungeness crabs.

[image error]Blue King Crab

King crabs have tails or abdomens which are fan-shaped and
are tucked underneath the rear of the shell. Of their five pairs of legs, the
first is their claws or pincers. The right claw is usually the largest. The
next three pairs are their walking legs, and the fifth pair of legs are small
and usually tucked underneath the rear of their carapace. Adult females use
these specialized legs to clean their embryos, and males use them to transfer sperm
to females during mating.

A crab’s skeleton is its external shell made of calcium. In
order to grow, a crab must periodically shed and grow a new, larger carapace,
during a process called molting. Juveniles molt frequently during their first
few years but less often when they reach sexual maturity at the age of four or
five years. Adult females must molt in order to mate, but a male does not need
to shed his shell to mate. Adult female red king crabs molt and mate once a
year, but males often keep the same shell for two years. King crabs shed their
shells by absorbing water, causing the shell to crack.

[image error]Golden King Crab

Red king crabs are the largest of the king crab species.
Blue crabs are the second largest, and golden king crabs are the third largest.
Female red king crabs reach a maximum weight of 10.5 lbs. (4.8 kg), and males
grow as large as 24 lbs. (10.9 kg). A large male has a leg span of nearly five
ft. (1.52 m) and a carapace as long as 11 inches (27.9 cm). King crabs can live
20 to 30 years.

[image error]Scarlet King Crab

Red, blue, and golden king crabs migrate annually from
nearshore to offshore. They migrate to shallow water in the late winter or
early spring where the female’s embryos hatch. Adult females and some adult
males then molt, and mating occurs before the crabs return to deep water. Once
they have mated, adults segregate by sex. Biologists studying male red king
crabs near Kodiak noted some males migrate up to 100 miles (161 km) round-trip
annually, and at times, they move as fast as a mile (1.6 km) per day. While
depth ranges and habitats overlap, red, blue, gold, and scarlet king crabs
rarely co-exist.

In my next post, I will cover the lifecycle and feeding
habits of king crabs as well as the status of king crab populations and the
threats they face.

Please sign up below for my newsletter about true murder and mystery in Alaska, and I invite you to listen to my podcast, Murder and Mystery in the Last Frontier.

[image error]







[image error]

Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

[image error]





Mystery NewsletterSign Up for my free, monthly Mystery Newsletter about true crime in Alaska.





Email Address












First Name












Last Name



















Sign Up For My Mystery Newsletter

The post Alaska King Crab appeared first on Robin Barefield.