Early Life History

1)King crabs extrude eggs within 24 hr of mating, and they are fertilized with spermatophores deposited by the male crab. Stages of development are shown below.

2)On day 1, the fertilized egg about 1 mm in diameter. It does not start to divide until day 4, after which it undergoes one division daily.

3)By day 12, the eggs are at the 256-512 cell stage.

4)The embryo becomes apparent after about 4 months. At this point ,only the eyes , abdomen, and mouthparts are visible.

5)About 6 months after fertilization, the eyes begin to form as small crescent slivers. Yolk occupies most of the egg.

6)At 13 months(388 days), the eyes are large, and the embryo is almost ready to hatch. The egg is 1.3 mm in diameter, and only a small amount of yolk remains. Chromatophores (red color cells) are easily seen. The abdomen (tail) is wrapped around and over the head.

7)Hatching occurs in the first 2 hours after dark and requires 30 days for each female. The pre-zoea quickly molts to the first zoeal stage. Larvae pass through 4 zoeal stages, requiring 30-60 days. They feed actively on diatoms and zooplankton.

8)After zoea stage IV, larvae metamorphose to the glacothoe stage, which lasts for 30-40 days. Glaucothoe actively seek structurally complex habitats for shelter. They live off stored energe and do not feed.

9)Glaucothoe molt to the first crab (C1) stage, and remain hidden. Coloration of the blue king crab closely matches its preferred habitat, broken shells.

堪察加拟石蟹早期生活史

Fig.10. Early Life History of King Crabs. Paralithodes camtschaticus and P. platypus From:https://seagrant.uaf.edu/factsheets/kingcrab/crablifehistory-poster.pdf

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