Unit One Introduction to Marine Invertebrates - the National Sea ...

The life history of the red king is
well known. Eggs hatch in the
spring, and the young drift in open
water for about two months before
settling to the sea floor. While
drifting, they molt several times
and begin to resemble adult crabs.
When small, the young kings hide
among rocks and algae to protect
themselves. As they grow older,
they join with other kings their own
size, and often form large groups,
or pods, that move over the sea
floor like a living ball of red spines
and tiny claws. At this stage,
they have traded hiding for sticking
together as a means of protection.
As each crab continues to
molt and grow, its size begins to
afford it protection, and individuals
move away from the pod.
With maturity, crabs follow another
pattern. For part of the year they
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live in deep water, but each year
in late winter or early spring they
move into shallow water to mate.
Beginning in late winter, males seek
out females and carry them in their
claws until the female molts. They
then mate and separate. The
female’s eggs are deposited under a
flap beneath her body and are
carried there for almost a year.
The following spring, the eggs
hatch and the cycle begins again.
Some adult males also molt while in
shallow water, but these will not
mate while their shells are soft.
Kings are easily identified by their
size and by the spininess of their
shells. No other commonly found
crab has well-spaced conical spines
over its back and legs. The king
has six walking legs and two claws,
the right claw larger than the left.
Tanner crab Dungeness crab