Crabs and Shellfish

<body> <p>More than any other animal, the <a href="blue_crab.cfm"><u>blue crab</u></a>, or <i>Callinectes sapidus</i>, symbolizes the life and culture of the Chesapeake Bay region. The beautifully colored, aggressive crab supports vital commercial and recreational fisheries. The Chesapeake Bay is the largest producer of crabs in the country; its estimated that more than a third of the nations catch of blue crabs comes from Bay waters. Commercial harvests in a good year can yield close to 100 million pounds of crab annually.</p> <p>Crabs belong to a group of animals called crustaceans, which includes shrimp, crayfish and lobsters. Their ten legs perform specialized tasks: they use their three middle legs for walking sideways on the Bay bottom and their front pair, strong pincer claws, for defense and predation; the remaining pairthe hind legs that resemble paddlesalso earn the crab part of its scientific name: <i>Callinectes</i> or "beautiful swimmer." </p> <p>Crabs inhabit a wide range of Bay waters, from the upper Bay near freshwater tributaries down to the saltier waters at the mouth of the Bay. Fisherman harvest blue crabs using baited trotlines, dip nets, crab pots, pound nets and crab scrapes, and they harvest either hard-shell crabs or "soft shells" that have just completed one of several molting phases. </p> <p>The <a href="american_oyster.cfm"><u>American Oyster</u></a> is another of the Bays most recognizable and sought-after bottom-dwelling animals. The oyster is an international delicacy, but since the late 1800s, overharvesting, parasites such as Dermo and MSX, and pollution have severely depleted oysters stocks in the Bay, which is one of the countrys foremost oyster producers. Larval oysters are swimmers, but after two to three weeks they migrate to the Bay bottom to attach to the substrate or "set." Thereafter oysters are referred to as "spat," and they spend their lives filtering Bay waters, consuming plankton, and reproducing. </p> <p>Another important mollusk that comes from the Bay is the <a href="hard_clam.cfm"><u>hard clam</u></a>, found primarily in the higher salinity waters of the Bay. Known variously as the round clam, cherrystone or quahog, hard clams also begin life as pelagic larvae and later bury themselves shallowly in mud with an organ known as their "foot" and thereafter begin to secrete their hard shells. Their spawning cycles are greatly affected by water temperatures and the availability of food. </p> <p>Crabs and shellfish share habitat and consequently respond to similar fluctuations in its quality. Juvenile crabs rely on <a href="baygras.cfm"><u>submerged aquatic vegetation (SAV)</u></a> for habitat and nursery grounds and feed on many benthic species, including other crustaceans and small fish. Oysters need clean surfaces on which to attach and are affected by increased sedimentation, which can smother spat or mature oysters. Clams also are vulnerable to toxins in the sediment.</p> <div align="center"> <center> <table border="1" cellpadding="0" cellspacing="0" width="100%"> <tr> <td bgcolor="#C6C68C"><strong>Other Sites of Interest:</strong> <ul> <li><a href="http://www.shellfish.org/" target="_top">National Shellfisheries Association</a></li> <li><a href="http://www.lam.mus.ca.us/~tcs/" target="_top">The Crustacean Society</a></li> </ul> </td> </tr> </table> </center> </div> <hr noshade> <p align="center"><font face="Times New Roman" size="2">To bookmark this page, please use this URL: <a href="http://www.chesapeakebay.net/crabshell.htm" target="_top">http://www.chesapeakebay.net/crabshell.htm</a> </font></p> <p align="center"><font size="2">For more information, contact the Chesapeake Bay Program Office, 410 Severn Avenue, Suite 109, Annapolis, MD 21403 /  Tel: (800) YOUR-BAY /   Fax: (410) 267-5777. </font></p> <p align="center"><font size="2"><a href="javascript:print()"><img src="images/print.gif" width="34" height="38" border="0" alt="Print Current Page" align="right"></a><a href="http://www.chesapeakebay.net/directions.htm" target="_top">Directions to the Bay Program Office</a><a href="http://www.chesapeakebay.net/cims" target="_top"><img src="images/cims1.gif" height="19" width="51" border="0" align="left"></a></font></p> <p align="center"><font size="2">Last modified: 11/26/03</font> </body>