Blue crab [1] [2] [3] [4] ( lat. Callinectes sapidus ) is a crustacean of the Portunidae family . First described by Mary Jane Rathban .
| Blue crab |
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| Scientific classification |
|---|
| No rank : | Bilateral symmetrical |
| Subsection : | Geterotremata |
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| International scientific name |
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Callinectes sapidus Rathbun , 1896 |
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The blue crab carapace reaches a width of 17.8–20 cm and a length of 7.5–10.2 cm. Males are larger than females [5] . The weight of sexually mature animals is from 0.45 to 0.90 kg. The dorsal carapace has a dark brown, grayish, greenish or bluish-green color and has orange spikes on each side up to 8 cm wide. The lower limbs and abdomen are whitish in color.
Claws have different color shades depending on gender. The tops of the claws of males are bluish, the females are reddish.
The blue crab has five pairs of chest limbs. The front pair of limbs is transformed into two strong claws of different sizes. A massive cracking claw serves to crack shells, while using a smaller claw, the crab breaks soft tissues and sends food to the mouth opening. The fifth pair of limbs is similar in shape to a kayak oar and serves for swimming. Blue crabs are capable of throwing claws in case of danger. Then the crab can recover the lost limbs.
Faceted eyes on short stems are located directly below the front edge of the carapace on the head. Between the eyes are two pairs of short and thin antennas.
The life span of a blue crab is approximately 2 to 4 years.
The original homeland of the blue crab is the Atlantic coast of North and South America. In Europe, this species was first discovered in 1900. Today it can be found in the vast territories of the Baltic and North Seas. It is also found in the Mediterranean and Adriatic seas.
Blue crab lives mainly in estuaries and in shallow water at a depth of 36 m, deeper in winter. He prefers muddy and sandy bottom.
Young crabs need a water temperature of 15 to 30 ° C. Adult animals can tolerate water temperatures of up to 10 ° C. Larvae, unlike young and adult animals, are demanding of the average salinity, not tolerating values below 20 ‰.
After mating, the females return to shallow salt water, while the males remain at the mouths of the rivers.
Most of the time, crabs hide in mud or sea grasses to watch over their prey or defend themselves from enemies. Blue crab is quite aggressive compared to other species.
Blue crab competes with other crustaceans for food. This is an omnivore. Its nutritional spectrum includes mollusks, such as, for example, mussels , young crustaceans, fish, worms, and also plants. It does not disdain to eat carrion. With a lack of food, the animal is prone to cannibalism .
The natural enemies of the blue crab include red croaker ( Sciaenops ocellatus ), common crocker ( Micropogonias undulatus ), American silver gull ( Larus argentatus smithsonianus ), various species of herons , as well as sea turtles .
Blue crab is considered a delicacy and is caught in large quantities.
The parasites and commensals of blue crabs include:
- sea acorns .
- other barnacles .
- nematodes .
- trematodes .
They can live on the shell, in the gill cavity, on the abdomen and inside the body of a blue crab. Most of these parasites do not seriously affect the life of an individual.
The blue crab becomes sexually mature at the age of 12 to 18 months. Females mate only once a year, immediately after molting, while males mate more often.
Like all crustaceans, the blue crab periodically molt throughout life. After molting, the carapace of the female is soft for a short time. The male uses this time to mate with the female. The female is capable of storing male sperm for quite some time. It spawns about 2 months after mating. Clutch consists of 2 million eggs. Spawning begins in December and ends in October, with the peak occurring in spring and summer. After the female lays eggs, the eggs are fertilized with stored sperm and attached to tiny hairs on her abdominal legs.
The incubation period is approximately 14 days. Within 2 months, planktonic larvae go through 8 stages before they acquire the appearance of crabs.
- ↑ Anosov S. E. Characterization of the Decapoda fauna of the Azov-Black Sea basin. Qualitative and quantitative changes over the last century. The dissertation for the degree of candidate of biological sciences . - M .: All-Russian Scientific Research Institute of Fisheries and Oceanography (FSBIU "VNIRO"), 2016. - P. 10, 128, 198-204. - 269 p.
- ↑ Ruppert E.E. Arthropods // Invertebrate Zoology: Functional and Evolutionary Aspects: a textbook for students. universities: in 4 tons / under the editorship of A. A. Dobrovolsky and A. I. Granovich. - M .: Publishing Center "Academy", 2008. - T. 3. - S. 266. - 496 p. - ISBN 978-5-7695-3496-6 .
- ↑ Monin V.L. A New Finding of the Blue Crab Callinectes sapidus (Decapoda, Brachyura) in the Black Sea // Zoological Journal , 1984, Volume 63, Issue 7. - P. 1100-1101.
- ↑ Pashkov A.N., Reshetnikov S.I., Bondarev K. B. The capture of blue crab ( Callinectes sapidus , Decapoda, Crustacea) in the Russian sector of the Black Sea // Russian Journal of Biological Invasions , 2011, No. 4. - P. 33 -42.
- ↑ Species Fact Sheets: Callinectes sapidus (Rathbun, 1896)
- Diverse: Grzimeks Tierleben. Niedere Tiere. 1.Bd. Deutscher Taschenbuch Verlag GmbH & Co.KG, München Oktober 1993
- Hans-Echhard Gruner, Hans-Joachim Hannemann und Gerhard Hartwich, Urania Tierreich, 7 Bde., Wirbellose Tiere, Urania, Freiburg, 1994
