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  • Blue Crab Anatomy (Female)
    Diagram courtesy of Richard Fox Lander University During spawning egg cells oocytes are forced from the ovaries through the seminal receptacles where they are fertilized The fertilized eggs which are about 0 25 mm in diameter are then extruded from the gonopores where they attach to the long setae of the pleopods to form a large cohesive mass or sponge that remains attached until they hatch i e the oocytes

    Original URL path: http://www.bluecrab.info/female_anatomy.htm (2016-05-02)
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  • BLUECRAB.INFO - Blue Crab Autotomy & Regeneration
    claw so the crab dropped it in an effort to flee Autotomy derived from the Latin words autos for self and tomos for cut occurs when a break develops along a special fracture plane located at the appendage s distal base When blue crabs are subjected to mechanical stimulus such as a predator attempting to remove them from rocks they respond by either fleeing or fighting When choosing to fight crabs will pinch the predator with its powerful claws hoping that the action will make the predator lose its grip When choosing to flee crabs will autotomize the limb s being held onto in order to escape Other reasons to autotomize a limb might be to reduce blood loss from a distal wound a response to physiological stress ill health or the presence of pests or bacteria Study the photo above left by looking closely at the base of the claw near the movable joint where it attaches to the main body You will see a thin oblique groove or fracture plane in the shell photo above right shows the fracture plane highlighted in red A crab can cause this fracture to break instantaneously separating limb from body This plane

    Original URL path: http://www.bluecrab.info/autotomy.html (2016-05-02)
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  • BLUECRAB.INFO - Blue Crab Taxonomy
    known and even our estimates are very rough Animals range in size from no more than a few cells to organisms weighing many tons such as blue whales and giant squid Most animals inhabit the seas with fewer in fresh water and even fewer on land Subkingdom Metazoa Subkingdom of the animal kingdom comprising the multicellular animals in the traditional two kingdom system of taxonomic classification in which living organisms were considered to be either plants or animals Metazoa included all animals except the protozoans formerly classified as in the phylum Protozoa but now classified in the kingdom Protista The term is still used informally Phylum Arthropoda Arthropoda is the largest and most diverse animal phylum It includes the trilobites chelicerates insects and crustaceans Arthropods have an exoskeleton that is molted periodically to accommodate growth The body is segmented and the segments bear paired jointed appendages Subphylum Crustacea Crustaceans are primarily aquatic arthropods The crustacean head consists of five fused segments and bears five pairs of appendages including two pairs of antennae Appendages are primitively biramous Excretion and osmoregulation are via modified metanephridia known as end sac organs respiration is via gills or a permeable body surface The brain is tripartite Compound eyes are frequently present Class Malacostraca Malacostraca is a large group that includes the crabs shrimps and lobsters as well as several less familiar crustaceans such as the peracarids Malacostracans are relatively unspecialized crustaceans with appendages on the abdomen The group is a large one and includes the largest crustaceans The malacostracan body consists of head thorax and abdomen each with a characteristic number of segments The head like that of all crustaceans consists of 5 fused segments The thorax consists of 8 and the abdomen of 6 There is usually a carapace over some or all of the thorax and some anterior thoracic appendages are usually modified as maxillipeds Subclass Eumalacostraca The Eumalacostraca Greek word for true soft shell are a subclass of crustaceans containing almost all living malacostracans about 22 000 described species Eumalacostracans have 19 segments 5 cephalic 8 thoracic 6 abdominal The thoracic limbs are jointed and used for swimming or walking The common ancestor is thought to have had a carapace and most living species possess one but it has been lost in some subgroups Superorder Eucarida Eucarida is a superorder of crustaceans comprising the decapods krill and Amphionides They are characterized by having the carapace fused to all thoracic segments and by the possession of stalked eyes Of all the groups of crustaceans the Eucarida appeared relatively late in the fossil record They first appear in the Mesozoic era but are presumed to have first evolved much earlier Order Decapoda The largest and most familiar crustaceans belong to the order Decapoda The familiar crabs shrimps crayfishes and lobsters are decapods The first three segments of the decapod thorax are associated with the head and their appendages are maxillipeds The remaining 5 thoracic appendages bear simple or chelate walking legs The resulting five

    Original URL path: http://www.bluecrab.info/taxonomy.html (2016-05-02)
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  • Blue crab molting signs
    reddish outline no larger than a fingernail clipping on the second segment of the swimming fin Sequence left to right mid cycle white sign pink sign red sign Photo courtesy of Alicia Young Williams Smithsonian Environmental Research Center Signs of Impending Molt White Sign Also known as snots or greens The white sign is simply the first faint outline of the second exoskeleton or new skin forming underneath the old as molting approaches It is very hard for laymen to distinguish It usually appears about two weeks prior to molting Pink Sign A pink mark that appears on the crab s backfin which indicates that it will molt in less than a week This marks the appearance of the new shell underneath its present hard shell Red Sign Hard crab which will molt in less than two days Amateurs can usually detect the red sign but with considerable practice Rank Peeler Hard crab which will molt in a matter of hours If you squeeze or pinch the end of a rank peeler s swimming fin the new soft shell underneath will be displaced as seen in this image Be sure to massage the fin back to its original position or the crab will hang up when it molts meaning that it will not be able to back out of its old shell completely leaving its new swimming fin behind Sign unique to female blue crabs The female blue crab has one additional sign which appears when an immature female crab or Sally is about to perform her final pre pubescent molt and become sexually mature thus becoming a Sook Simply examine her abdomen and note the color of her apron A red sign Sally will have a dark purple colored abdomen See images below Green Sally or She Crab Red

    Original URL path: http://www.bluecrab.info/redsign.htm (2016-05-02)
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  • Molting and the Full Moon
    cavity cramping etc it will not enter the molting cycle In other words if it doesn t get enough to eat then it s not going to outgrow its shell Jennifer Martin of the University of Connecticut s Department of Ecology and Evolution says In the lab I had two thousand crabs that I was rearing and a full moon definitely meant most of them were molting Why I am not sure This would seem to indicate that the increased gravitational pull during a full moon somehow directly influences the crab since food availability and cover would not be factors in a controlled laboratory environment From a skeptical point of view there is a more realistic explanation The lunar cycle month is fixed at 29 53 days This means that the oceans and other water bodies which are affected by the earth moon system experience a new tidal cycle roughly every 30 days The Atlantic blue crab molts about 18 to 23 times not including larval molts during its life The instar or period between molts grows progressively longer as the crab gets older ranging from 10 15 days for one inchers to 30 50 days for legal size keepers and beyond Because the lunar cycle occurs at a fixed 29 53 day interval and because the molting cycle is variable as low as every 10 days to as high as every 50 days any correlation between the two is purely coincidental Perhaps it s because the 30 day lunar cycle roughly correlates to the 30 day molting interval of legal size keepers that people tend take special notice For example Small immature crabs have a short 10 20 day molting cycle which does not correlate to the lunar cycle Since these crabs are of no commercial interest their molting behavior is not closely monitored Legal size hard crabs have an approximate 30 day molting cycle This very closely matches that of the lunar cycle Because of their high commercial value crabs of this size are placed in holding tanks and are monitored very closely until they molt Special notice is taken when totally by coincidence crabs are seen molting during a full moon This is called subjective validation or selective memory Subjective validation is a psychological phenomenon in which people tend to remember significant or coincidental events and forget the others Large hard crabs those with a molting cycle in the 40 50 day range are scarce and therefore are not monitored as closely So are peelers are more prevalent during a full moon Probably not While it s difficult to argue against the fact that some commercial harvesters claim to see a correlation we should take this with a grain of salt We know that a crab s molting cycle is variable and the lunar cycle is fixed It is also a fact of human nature that we try to attach special meanings and significance to things that occur in regular cycles especially when they seem to coincide

    Original URL path: http://www.bluecrab.info/fullmoon.htm (2016-05-02)
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  • BLUECRAB.INFO - Blue Crab Life Cycle
    Numbers Correspond to the Day of Development Days 1 5 left column considered orange yellow Days 6 10 center column considered brown Days 11 15 right column considered black 2006

    Original URL path: http://www.bluecrab.info/spongers.html (2016-05-02)
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  • Buying Hard Shell Crabs
    the dozen or by the bushel A dozen crabs is exactly 12 crabs The actual number of crabs in a bushel depends on the size of the crabs See the following table for the approximate number of crabs per bushel SIZE CRAB DIMENSIONS DOZENS PER BUSHEL CRABS PER BUSHEL Jumbo 6 6 ½ inches 5 6 dozen 60 72 crabs Large 5 ½ 6 inches 6 7 dozen 72 84 crabs Medium 5 5 ½ inches 7 8 dozen 84 96 crabs Generally speaking a bushel of Number Ones will hold 60 70 crabs depending on how big the crabs are at that time of year If there are 60 70 crabs they will feed about 10 12 people depending upon what else is on the menu If you have all kinds of food such as salads hot dogs chicken etc you ll probably need half as many crabs If you serve only steamed crabs clams corn and beverages you ll need the whole bushel Availability Availability Blue crab meat is available year round in the pasteurized form live crabs are seasonal and much more plentiful during the warm water months of the year Fresh or pasteurized cooked crab meat is usually available for purchase as lump flake or claw meat lump meat consists of whole lumps from the large body muscles which operate the swimming legs flake meat consists of small pieces of white meat from the body claw meat consists of a brownish tinged meat from the claws See the crab glossary for more specific information Yields Yields An average blue crab weighs about 1 3 pound with the edible portion quite low An experienced crab picker can produce about 2 1 4 ounces of meat from each pound of live blue crabs This is about a 14 yield The actual yield depends on the size of the individual crab and experience of the crab picker The consumer is probably better off to purchase the crab meat already prepared unless the picking is incorporated into a crab boil or picnic type activity You can estimate a price comparison between fresh and pasteurized meat by studying the following example Pay 10 00 per dozen 1 crab 1 3 pound Dozen crabs 4 pounds Yield From One Pound of Live Crabs X Total Pounds of Live Crabs Crab Meat Yield 0 14 x 4 pounds 0 56 pounds meat Cost per Dozen Pounds of Meat Cost per Pound 10 00 0 56 pounds 17 85 per pound A pound of crab meat already prepared and selling for less than 17 85 would be the best buy If the prepared pound costs more than 17 85 buy the dozen for 10 00 and pick your own if your labor is cheap and you have the time Yield information courtesy of the Florida Sea Grant College Program and author Don E Sweat The full publication can be found here Storage Stor age Hard blue crabs are always marketed live Crabs that have

    Original URL path: http://www.bluecrab.info/buying_hards.htm (2016-05-02)
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  • Buying Soft Shell Crabs
    shell in approximately 7 10 days If the line is pink the crab is likely to shed within 2 days and probably not longer than one week If the little line on the backfin is red the crab is likely to shed its shell at any time Soft shells are split up into 5 basic sizes whales jumbos primes hotels and mediums A sizing and weight chart is provided as follows SIZE DIMENSIONS AVERAGE WEIGHT DOZENS PER TRAY DOZENS PER CASE Whales 5 ½ inches 5 9 oz 2 6 Jumbos 5 5 ½ inches 4 5 oz 3 9 Primes 4 ½ 5 inches 3 3 oz 4 12 Hotels 4 4 ½ inches 2 5 oz 5 15 Mediums 3 ½ 4 inches 1 8 oz 6 18 While the number of soft shells per tray varies by size and by producer common shipping quantities are in the table above Soft shell crab is shipped live but typically marketed as fresh In many cases the soft shell crab move when touched If they are hearty and strong they will arrive live However it is most common for them to perish in transit Motion and heat are the biggest factors affecting the Blue Crabs mortality The only real indicator to determine the freshness of the blue crab is the smell Blue crabs that have a distinct ammonia odor should not be served Blue crab that have perished but have no odor are still fresh enough to eat A much debuted measure of freshness is firmness and texture Firmness is debated because it can be influenced by temperature A 50 degree still will be softer than a 36 degree still yet both can have equal freshness The best way to store a soft shell crab is in cool moist packaging

    Original URL path: http://www.bluecrab.info/buying_softs.htm (2016-05-02)
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