Molt and Growth of Red Snow Crab Chionoecetes japonicus Observed in the Rearing Condition

Abstract

To clarify the growth and intermolt period in the red snow crab Chionoecetes japonicus, 3 male and 15 female immature crabs were collected from Toyama Bay, the Japan Sea, from July 1999 to July 2002, and were reared in the laboratory until 2 February 2004. A total of 39 molts were observed during the rearing experiment; in the maximum case, a crab molted 6 times during a period of 4.5 years. Carapace width (CW) growth increment increased with body size in the molts of both male and female juvenile crabs, whereas it remained unchanged regardless of body size in the female crab's terminal molt. Moreover, the liner regression line between premolt and postmolt CW differed between juvenile and terminal molts in females, which might suggest that the growth pattern changed at maturation. A liner relationship was exhibited between the premolt CW (Ln) and intermolt period (IP) and is described by the equation: IP (days) = 4.773Ln (mm) + 147.3; r² = 0.737, P < 0.001, n = 21.