Blue Crabs Essay, Research Paper

The scientific name given to the blue crab was derived from Latin and Greek:

Calli, beautiful; nectes, swimmer; and sapidus, savory. Thus, a literal

transition might be the beautiful savory swimmer.

The blue crab is an important and interesting species. The blue crab is

a species whose life history involves a complex cycle of planktonic, nektonic,

and benthic stages which occur throughout the marine environment in a

variety of habitats. The blue crab is one of the more abundant estuarine

invertebrates and supports important commercial and recreational fisheries

along the Atlantic and Gulf coasts. The blue crab plays an important role in

the marine food web, providing prey for many species and a predator on other

species. The blue crab is a highly prized commodity to consumers.

Eight species of Callinectes have been documented in the Gulf of

Mexico: C. bocourti, C. danae, C. ornatus, C. exasperatus, C. marginatus, C.

similis and C. rathbunae, and Callinectes sapidus.

The original range of the blue crab is from Nova Scotia and throughout

the Gulf of Mexico to northern Argentina. The blue crab is rarely found north

of Cape Cod, but has been recorded in Maine and Nova Scotia. The blue crab

has been introduced into Europe, North Africa, and Southwest Asia.

Introductions into the Mediterranean Sea and surrounding waters have

produced breeding populations whereas others were probably temporary

occurrences. The blue crab also has been introduced into Japan.

Blue crabs are one of the most common marine invertebrates and are

generally abundant throughout the oceans. Peak abundance of adult crabs

occurs during the warmer months. During winter, crabs are found in areas of

tidal exchange in the lower estuary. Juvenile blue crabs are most abundant in

waters of low to intermediate salinity during the winter months.

Males become sexually mature at the 18 or 19th molt but may continue

to grow and molt an additional 3-4 times thereafter. Female crabs were

initially thought to rarely, if ever, molt again following their mature molt.

However, mature females undergoing a second molt have been verified.

No data on maximum age of blue crabs is available from the Gulf of

Mexico, although it has been estimated to reach a maximum age of 4 years in

Florida and 7-8 years in Chesapeake Bay.

Autotomy (voluntary breaking of appendages) and regeneration are

common in blue crabs. One survey found that 19-25% of blue crabs were

either missing or regenerating a limb. A functional appendage is formed by

regeneration following the next molt, although three molts may be required

for 100% limb regeneration.