Blue crab [1] ( lat. Paralithodes platypus ) is a species of hermit crabs from the Lithodidae family . Treats kraboidam: representatives possess external similarity to crabs ( Brachyura ), but are easily distinguishable by the reduced fifth pair of walking legs and asymmetrical abdomen in females [2] . The maximum life expectancy of 22-25 years [3] .
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| Paralithodes platypus ( Brandt , 1850) |
Content
Appearance and build
Very reminiscent of Kamchatka crab . The carapace width of males is up to 22 cm, females up to 16 cm. Maximum weight is 5 kg. In the area of the heart on carapax there are two pairs of large spines, there may also be several small spines. The end of the rostrum is sharp, somewhat curved downward. On top of the rostrum there are two large spines and one or two small spines. The mobile thorn at the base of the external antenna is branched into three parts. The torso and limbs are painted red-brown with blue, and yellowish-white from below. On the sides of the body and limbs yellow-orange spots. Individuals from the Bering Sea are yellow-orange in color much less than in the inhabitants of the northeastern part of the Sea of Okhotsk. Young blue crabs do not have thorns, and in their place are rounded tubercles [4] .
Distribution and habitat
Inhabits the Bering , Okhotsk and Japan Seas [3] . In winter, kept at a depth of 300 meters.
Reproduction
Blue crab females from the northeastern part of the Sea of Okhotsk spawn once every two years. There are two generations in this population that breed in even and odd years. Females of this population spawn from March to early April, and the larvae hatch in April — May. Thus, caviar develops 12-13 months.
Females bearing fertilized eggs stay at a depth of about 100 meters. In autumn, females ready for breeding concentrate at a depth of 120-130 meters. In December, they go to depths of more than 200 meters in areas where the majority of males spend the winter. In spring, these females molt, mating and laying of calf occur, and then females go back to shallow water [5] .
Blue crab and man
Being one of the largest crustaceans of the Far East , the blue crab acts as an object of harvest.
Notes
- ↑ Atlas of Invertebrates of the Far Eastern Seas of the USSR / ch. ed. Acad. E. N. Pavlovsky . - M.-L., Publishing House of the Academy of Sciences of the USSR, 1955. - P. 154.
- Ruppert E.E., Fox R.S., Barnes R.D., Invertebrate Zoology: Functional and Evolutionary Aspects. T. 3: Arthropods. - M .: Publishing Center "Academy", 2008. - 496 p.
- ↑ 1 2 Plants and animals of the Sea of Japan: a brief atlas-determinant. - Vladivostok: Far Eastern University Publishing House, 2007.
- ↑ Slizkin A., Safronov S. Commercial crabs of Kamchatka waters . - Petropavlovsk-Kamchatsky: Northern Pacic, 2000. - pp. 35-36.
- ↑ Lysenko V.N. (2001). Peculiarities of the biology of females of the blue crab Paralithodes platypus in the northeastern part of the Sea of Okhotsk // Izvestiya TINRO, vol. 128 (1-2), p. 523-532. annotation