Biological and oceanographic background

Three species of king crab are harvested in the eastern North Pacific:

• Paralithodes camtschatica (red);

• Paralithodes platypus (blue) ;

• Lithodes aequispina (brown).

Of these, red king crab is by far the most important and occurs on the shelf in the eastern Bering Sea, Aleutian Islands, edge of the Gulf of Alaska to SE Alaska, and northern British Columbia.*

While adults feed offshore and migrate inshore for spawning, juveniles are found in the littoral zone and shallow water. In the Bering Sea, adults prefer bottom temperatures of 0° to 5.5°C, suggesting a temperature influence on distribution.

Molting and spawning take place in shallow (10-50m) waters in late winter and early spring. Males molt in March-April, females just before spawning in April-May (see Fig. 2.3). Eggs, 50,000 to 400,000 in number, are attached to females and develop for 11 months, normally hatching in April-May (timing can vary by

* This summary of king crab biology is based mainly on Hayes, 1983.

more than one month in different years). Five successive larval stages live as plankton in the water column for a total of about six weeks, then settle to the bottom.

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