Early Life History of King Crabs, Paralithodes camtschaticus and P. platypus Bradley G. Stevens 1 , Kathy Swiney 2 , and Sara Persselin 2 Red and blue king crabs (Paralithodes camtschaticus and P. platypus, respectively) supported valuable commercial fisheries in the Bering Sea. In 1998, populations of blue king crabs declined dramatically and its fishery was closed. Research on king crab life history has focused on the first year of life, from fertilization, through embryo development, hatching, larval development, settling, and juvenile growth. This poster documents important events in the life cycle of the king crab. 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. Glaucothoe molt to the first crab (C1) stage, and remain hidden. Coloration of the blue king crab closely matches its preferred habitat, broken shells. This research was partially supported by a grant from the North Pacific Research Board. All photographs by Brad Stevens. Red king crab female Blue king crab female with fertilized eggs On day 1, the fertilized egg is about 1 mm in diameter. It does not start to divide until day 4, after which it undergoes one division daily By day 12, the eggs are at the 256-512 cell stage. The embryo becomes apparent after about 4 months. At this point, only the eyes, abdomen, and mouthparts are visible. About 6 months after fertilization, the eyes begin to form as small crescent slivers. Yolk occupies most of the egg. 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. 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 (ZI). Larvae pass through 4 zoeal stages, requiring 30-60 days. They feed actively on diatoms and zooplankton. 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 energy and do not feed. Above: A male red king crab holds a female with his claws in a premating embrace. Yolk Eye Heart Abdomen 1 University of Massachusetts, Dartmouth School of Marine Science and Technology 706 S. Rodney French Blvd. New Bedford, MA 02744 [email protected] 2 National Marine Fisheries Service Kodiak Fisheries Research Center 301 Research Court Kodiak, AK 99615

Early Life History of King Crabs, Paralithodes ...closed. Research on king crab life history has focused on the first year of life, from fertilization, through embryo development,

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Page 1: Early Life History of King Crabs, Paralithodes ...closed. Research on king crab life history has focused on the first year of life, from fertilization, through embryo development,

Early Life History of King Crabs,Paralithodes camtschaticus and P. platypus

Bradley G. Stevens1, Kathy Swiney2, and Sara Persselin2

Red and blue king crabs (Paralithodescamtschaticus and P. platypus, respectively)supported valuable commercial fisheries in theBering Sea. In 1998, populations of blue kingcrabs declined dramatically and its fishery wasclosed. Research on king crab life history hasfocused on the first year of life, from fertilization,through embryo development, hatching, larvaldevelopment, settling, and juvenile growth. Thisposter documents important events in the lifecycle of the king crab.

King crabs extrude eggs within 24 hr of mating, and theyare fertilized with spermatophores deposited by the malecrab. Stages of development are shown below.

Glaucothoe molt to the first crab (C1) stage, and remainhidden. Coloration of the blue king crab closelymatches its preferred habitat, broken shells.

This research was partially supported by agrant from the North Pacific Research Board.All photographs by Brad Stevens.

Red king crab femaleBlue king crab female with fertilized eggs

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

By day 12, the eggs are at the 256-512 cell stage. The embryo becomes apparent after about 4 months.At this point, only the eyes, abdomen, and mouthpartsare visible.

About 6 months after fertilization, the eyes begin toform as small crescent slivers. Yolk occupies most ofthe egg.

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

Hatching occurs in the first 2 hours after dark andrequires 30 days for each female. The pre-zoeaquickly molts to the first zoeal stage (ZI). Larvae passthrough 4 zoeal stages, requiring 30-60 days. Theyfeed actively on diatoms and zooplankton.

After zoea stage IV, larvae metamorphose to theglacothoe stage, which lasts for 30-40 days.Glaucothoe actively seek structurally complex habitatsfor shelter. They live off stored energy and do not feed.

Above: A male red king crab holds a female with his claws in a premating embrace.

Yolk Eye

Heart Abdomen

1 University of Massachusetts, Dartmouth School of Marine Science and Technology 706 S. Rodney French Blvd. New Bedford, MA 02744 [email protected]

2 National Marine Fisheries Service Kodiak Fisheries Research Center 301 Research Court Kodiak, AK 99615