Blue Crab Life Cycle Create by Dave Werner MATES website of information:

Mating Female blue crabs mate only once in their lives Female blue crabs mate only once in their lives immediately following the last molt, the female is known as a "sook.“ immediately following the last molt, the female is known as a "sook.“ females release a pheromone in their urine which attracts males. females release a pheromone in their urine which attracts males. Male crabs vie for females and will carry and protect them, called "cradle carrying," until molting occurs Male crabs vie for females and will carry and protect them, called "cradle carrying," until molting occurs when the female's shell is soft, the pair will mate when the female's shell is soft, the pair will mate the female captures and stores the male's sperm in sac-like receptacles so that she can fertilize her eggs at a later time the female captures and stores the male's sperm in sac-like receptacles so that she can fertilize her eggs at a later time Once the female's shell has hardened, the male will release her and she will migrate to higher salinity waters to spawn. Once the female's shell has hardened, the male will release her and she will migrate to higher salinity waters to spawn.

Spawning After mating, females migrate to high-salinity waters in lower estuaries, sounds, and near-shore spawning areas. After mating, females migrate to high-salinity waters in lower estuaries, sounds, and near-shore spawning areas. They over-winter before spawning by burrowing in the mud. They over-winter before spawning by burrowing in the mud. Most females spawn for the first time two to nine months after mating, usually from May through August the following season. Most females spawn for the first time two to nine months after mating, usually from May through August the following season. The female extrudes fertilized eggs into a cohesive mass, or "sponge," that remains attached to her abdomen until the larvae emerge. The female extrudes fertilized eggs into a cohesive mass, or "sponge," that remains attached to her abdomen until the larvae emerge. The average sponge contains about two million eggs and is formed in about two hours. The average sponge contains about two million eggs and is formed in about two hours. Christmas Crab Video – Youtube Christmas Crab Video – Youtube Christmas Crab Video – Youtube Christmas Crab Video – Youtube Christmas Island Crabs – Youtube Christmas Island Crabs – Youtube Christmas Island Crabs – Youtube Christmas Island Crabs – Youtube

Growth Stages Growth and development of the blue crab, as in other crustaceans, consist of a series of larval, juvenile, and adult stages during which a variety of morphological, behavioral, and physiological changes occur. These changes are most dramatic when the animal molts (sheds its rigid exoskeleton) permitting growth and changes in body shape. Growth and development of the blue crab, as in other crustaceans, consist of a series of larval, juvenile, and adult stages during which a variety of morphological, behavioral, and physiological changes occur. These changes are most dramatic when the animal molts (sheds its rigid exoskeleton) permitting growth and changes in body shape. Before molting, a new shell is formed underneath the old exoskeleton, which then loosens and is cast off. The new shell is initially soft, but it expands and hardens in a few hours. Before molting, a new shell is formed underneath the old exoskeleton, which then loosens and is cast off. The new shell is initially soft, but it expands and hardens in a few hours. The stage between molts is termed intermolt. The stage between molts is termed intermolt.

Stage 1 – Zoeae Table 7.37p.142 or p.135 First stage larvae, called zoeae, measure approximately 0.25 mm at hatching. First stage larvae, called zoeae, measure approximately 0.25 mm at hatching. They bear little morphological resemblance to adults (Hopkins 1943), are filter feeders, and live a planktonic existence in the high-salinity surface waters near the spawning grounds (Pyle and Cronin 1950; Darnell 1959). They bear little morphological resemblance to adults (Hopkins 1943), are filter feeders, and live a planktonic existence in the high-salinity surface waters near the spawning grounds (Pyle and Cronin 1950; Darnell 1959). Tagatz (1968) found more zoeae near the water's surface than at the bottom. Evidence suggests that blue crab zoeae hatch in the Chesapeake Bay, Chincoteague Bay, Delaware Bay, and other estuaries and drift out to sea, where they feed and grow. Tagatz (1968) found more zoeae near the water's surface than at the bottom. Evidence suggests that blue crab zoeae hatch in the Chesapeake Bay, Chincoteague Bay, Delaware Bay, and other estuaries and drift out to sea, where they feed and grow. These larvae may migrate vertically in the water column to reach flood and ebb tides, which transport them back into the bay area. These larvae may migrate vertically in the water column to reach flood and ebb tides, which transport them back into the bay area.

Stage 1 – Zoeae Continued The zoeae and all subsequent life stages can increase body size only by molting (Hay 1905; Pyle and Cronin 1950). Zoeal development may require 31 to 49 days, depending on salinity and temperature, but development time has been shown to be variable even in a single salinity-temperature regime (Williams 1965). The zoeae and all subsequent life stages can increase body size only by molting (Hay 1905; Pyle and Cronin 1950). Zoeal development may require 31 to 49 days, depending on salinity and temperature, but development time has been shown to be variable even in a single salinity-temperature regime (Williams 1965). Zoeae molt four to seven times before entering the next stage of development. Zoeae molt four to seven times before entering the next stage of development. The final zoeal stage is about 1.0 mm in width (Hopkins, Rogers 1944). The final zoeal stage is about 1.0 mm in width (Hopkins, Rogers 1944).

Stage 2 - Megalops The final molt of the zoeae is characterized by a conspicuous change to the second larval stage, called a megalops (also termed megalopa [singular] or megalopae [plural]. The final molt of the zoeae is characterized by a conspicuous change to the second larval stage, called a megalops (also termed megalopa [singular] or megalopae [plural]. Development to this stage requires 31 to 49 days. The megalops larva is more crablike in appearance than the zoeae, its carapace is broader in relation to its length, and has biting claws and pointed joints at the ends of the legs. Development to this stage requires 31 to 49 days. The megalops larva is more crablike in appearance than the zoeae, its carapace is broader in relation to its length, and has biting claws and pointed joints at the ends of the legs. It measures about 1.0 mm in width. The megalops swims freely, but generally stays near the bottom in nearshore or lower-estuarine, high-salinity areas (Tagatz, 1968). The megalops stage lasts 6 to 20 days, after which the megalops molts into the "first crab" stage, with proportions and appearance more like those of an adult. It measures about 1.0 mm in width. The megalops swims freely, but generally stays near the bottom in nearshore or lower-estuarine, high-salinity areas (Tagatz, 1968). The megalops stage lasts 6 to 20 days, after which the megalops molts into the "first crab" stage, with proportions and appearance more like those of an adult. There are usually seven zoeal stages and one postlarval, or megalopal, stage. On occasion, an eighth zoeal stage is observed. There are usually seven zoeal stages and one postlarval, or megalopal, stage. On occasion, an eighth zoeal stage is observed.

Juveniles The juvenile "first crab" is typically 2.5 mm wide (from tip to tip of the lateral spines of the carapace). The juvenile "first crab" is typically 2.5 mm wide (from tip to tip of the lateral spines of the carapace). These juveniles gradually migrate into shallower, less-saline waters in upper estuaries and rivers where they grow and mature (Fischler and Walburg 1962). These juveniles gradually migrate into shallower, less-saline waters in upper estuaries and rivers where they grow and mature (Fischler and Walburg 1962). Van Engle (1958) and Tagatz (1968) reported that many juveniles had completed this migration by fall and early winter. New evidence, however, suggests the bulk may not reach the upper parts of tributaries and Chesapeake Bay until the following summer. Van Engle (1958) and Tagatz (1968) reported that many juveniles had completed this migration by fall and early winter. New evidence, however, suggests the bulk may not reach the upper parts of tributaries and Chesapeake Bay until the following summer. Males generally migrate farther upstream, preferring low-salinity waters, whereas females tend to stay in lower rivers and estuaries (Dudley and Judy 1971; Music 1979). Males generally migrate farther upstream, preferring low-salinity waters, whereas females tend to stay in lower rivers and estuaries (Dudley and Judy 1971; Music 1979). Molting and growing stop during winter (Churchill, 1921; Darnell 1959); growth resumes as waters warm, and juveniles generally reach maturity during the spring or summer of the year following their hatching. Molting and growing stop during winter (Churchill, 1921; Darnell 1959); growth resumes as waters warm, and juveniles generally reach maturity during the spring or summer of the year following their hatching.

Adults sexual maturity is reached after 18 to 20 postlarval molts, at the age of 1 to 1½ years sexual maturity is reached after 18 to 20 postlarval molts, at the age of 1 to 1½ years Males continue to molt and grow after they reach sexual maturity Males continue to molt and grow after they reach sexual maturity females cease to molt and grow (terminal molt) when they mature and mate females cease to molt and grow (terminal molt) when they mature and mate

Why do females stop molting? Is there an advantage to this???

Answer Molting takes energy; energy that is better used for reproductive output. Since it takes more energy to produce eggs, the theory is that mature female crabs don't grow as large or molt as frequently because of their reproductive energetics. Molting takes energy; energy that is better used for reproductive output. Since it takes more energy to produce eggs, the theory is that mature female crabs don't grow as large or molt as frequently because of their reproductive energetics. The converse is that sperm production is cheap, so males don't put energy into reproduction, rather they put it into somatic growth. The converse is that sperm production is cheap, so males don't put energy into reproduction, rather they put it into somatic growth.

Other molting theories… Molting is energy dependent. Larger animals must store far more nutrients for molting than do smaller juveniles. Thus, a really big lobster only molts every 2 to 5 to 10 years. Similarly for blue crabs, the larger the crab, the more difficult to store energy for molting. Molting is energy dependent. Larger animals must store far more nutrients for molting than do smaller juveniles. Thus, a really big lobster only molts every 2 to 5 to 10 years. Similarly for blue crabs, the larger the crab, the more difficult to store energy for molting. Molting is risky business. Larger animals may be at more risk, hence, they are not frequent in the population. Molting is risky business. Larger animals may be at more risk, hence, they are not frequent in the population.

Where do they go as adults? After the females mate and migrate to spawning areas, they either remain there for the rest of their lives or move only short distances out to sea. After the females mate and migrate to spawning areas, they either remain there for the rest of their lives or move only short distances out to sea. In warmer months, males generally stay in low-salinity waters such as creeks, rivers, and upper estuaries. In warmer months, males generally stay in low-salinity waters such as creeks, rivers, and upper estuaries. Research on blue crabs in the Chesapeake Bay indicated that females over-wintered at the mouth of the bay and spawned there in spring, whereas the migration of males was non-directional. Research on blue crabs in the Chesapeake Bay indicated that females over-wintered at the mouth of the bay and spawned there in spring, whereas the migration of males was non-directional. Crabs bury themselves in mud in winter and emerge when temperatures rise in spring. Crabs bury themselves in mud in winter and emerge when temperatures rise in spring. The maximum age for most blue crabs in the Mid-Atlantic Region is three years; adults thus live an average of less than one year after reaching maturity. The maximum age for most blue crabs in the Mid-Atlantic Region is three years; adults thus live an average of less than one year after reaching maturity.

Autotomy & Regeneration Blue crabs have the ability to sacrifice limbs (called autotomy) in order avoid capture. Missing limbs are regrown by a process called regeneration. Blue crabs have the ability to sacrifice limbs (called autotomy) in order avoid capture. Missing limbs are regrown by a process called regeneration. See crab.org/autotomy.html for detailed information. See crab.org/autotomy.html for detailed information. crab.org/autotomy.htmlhttp:// crab.org/autotomy.html

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Taxonomy Superkingdom:EukaryotaAll animals, plants, fungi, and protists. Superkingdom:EukaryotaAll animals, plants, fungi, and protists.Eukaryota Kingdom:AnimaliaAnimals. Kingdom:AnimaliaAnimals.Animalia Subkingdom:MetazoaMulticellular animals. Subkingdom:MetazoaMulticellular animals.Metazoa Phylum:ArthropodaJointed leg invertebrates. Phylum:ArthropodaJointed leg invertebrates.Arthropoda Subphylum:CrustaceaHaving a crustlike shell. Subphylum:CrustaceaHaving a crustlike shell.Crustacea Class:MalacostracaShrimps, Crabs, Lobsters. Class:MalacostracaShrimps, Crabs, Lobsters.Malacostraca Subclass:EumalacostracaHave a (head-thorax-abdomen) segment body plan. Subclass:EumalacostracaHave a (head-thorax-abdomen) segment body plan.Eumalacostraca Superorder:EucaridaCharacterized by having the carapace fused to all thoracic segments, and by the possession of stalked eyes. Superorder:EucaridaCharacterized by having the carapace fused to all thoracic segments, and by the possession of stalked eyes.Eucarida Order:DecapodaTen legs. Order:DecapodaTen legs.Decapoda Suborder:PleocyemataGills lacking secondary branches and eggs carried on pleopods before hatching. Suborder:PleocyemataGills lacking secondary branches and eggs carried on pleopods before hatching.Pleocyemata Infraorder:BrachyuraTrue crabs. Characterized by a reduced abdomen, folded beneath the cephalothorax, and inserted between the pereiopods or in a special cavity, which prevents it from impeding movements. Infraorder:BrachyuraTrue crabs. Characterized by a reduced abdomen, folded beneath the cephalothorax, and inserted between the pereiopods or in a special cavity, which prevents it from impeding movements.Brachyura Section:EubrachyuraPress-button holding system, consisting of a prominence always on the fifth sternite and a socket always positioned on the sixth abdominal segment. Prevents abdomen from moving. Section:EubrachyuraPress-button holding system, consisting of a prominence always on the fifth sternite and a socket always positioned on the sixth abdominal segment. Prevents abdomen from moving. Subsection:HeterotremataGroup in which the genital openings of the males are on the appendages and those of the females are on the thorax. Subsection:HeterotremataGroup in which the genital openings of the males are on the appendages and those of the females are on the thorax. Superfamily:Portunoidea Superfamily:Portunoidea Family:PortunidaeSwimming crabs. Family:PortunidaeSwimming crabs.Portunidae Subfamily:Portuninae Subfamily:Portuninae Genus:CallinectesGreek word for beautiful swimmer (Calli = beautiful, Nectes = swimmer). Genus:CallinectesGreek word for beautiful swimmer (Calli = beautiful, Nectes = swimmer). Species:SapidusLatin word for savory. Species:SapidusLatin word for savory. Scientific name:Callinectes sapidus Scientific name:Callinectes sapidus