The sea is full of many different species of crabs. I'll be covering three species of crabs. The species I'll be covering are blue crabs, hermit crabs, and fiddler crabs. .
The topics of growth, reproduction, and characteristics will also be covered.
April 27, 1998.
Period 3 .
Blue crabs come from the family Portunidae a group of animals having jointed legs, segmented body, and a hard outer shell. (Capossela, 1990) It is a crustacean as are lobsters and shrimps. This crab stays in water although it could survive shortly out of it.
The growth of blue crabs is slowed in areas of high salinity. In the waters of average salinity, male crabs may grow to seven-nine inches. Females seldom make it past six. They can live an average of 2-2 1/2 years, although some make it to four years of age. The crab has to shed his hard shell in order to grow. It sometimes has to do this 25-30 times in his life, for about two days each. At this time the crab is called a "softshell.” (Capossela, 1990) Small crabs shed every 3-5 days.
The blue crab occurs along the Atlantic Coast from Cape Cod south to Florida and around the Golf of Mexico to the Mississippi, and next to the lobster is our most valuable food crustacean being highly valued for its edible qualities. It is also known as the hard-shell or soft-shell crab, suitable for the market not only when the shell is hard but also immediately after molting before the new shell has hardened (Headstorm, 1985).
Between late spring and late summer, the abdomen of a mature female crab .
will bulge with an egg mass of about 700,000 to two million eggs. The mass gradually turns from bright orange to yellow or brownish and then to blackish as they consume the individual egg yolks. The female at this time is called a "sponge crab,” and must be returned in some states. (Bower, 1994) When the eggs hatch, they're very small and become part of a planktonic mass.