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Dug down during the winter
During the winter the shore crab is rather
sluggish and passive. During this period they are often found dug
down into the bottom sediment in shallow water. Here, the water is
a little warmer and there is little risk of hem being caught in the ice.
Ice can stop the flow of oxygen from the air to the water and give rise
to oxygen deficency where the water is shallow and the currents are weak.
Over the world
Shore crabs have larvae that can drift
over vast areas with sea
currents. Adult crabs can start on long journeys. If adult crabs are
marked, it is possible for them cover large distances even after a few
months.
Shore crabs are found along the whole of the eastern Atlantic
seaboard, from Norway to West Afrika. They are even found in the Mediterranean
and have been introduced to many other places in the world, for example
NE America.
Males and females
Shore crabs became sexually mature at
about 1 year. At this time they are about 2-3 cm over the carapace. Shore
crabs can be as old as 4 years. The males are normally larger than females
of the same age.
It is easy to distinguish the gender of adult shore crabs.
By closely studying their tails that are tucked in under their bodies
it is possible deduce their sex. Tails on the males
have 5 segments and are slim and pointed, whereas on the females
the tail has 7 segments, is wider and rounded.
The female uses her wider tail to protect the fertilized
eggs. Beside her tail she has four brush furnished legs where she can
stick her eggs.
Most shore crabs mate
during the late summer or early autumn.
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