Growth of juvenile red king crabs, paralithodes camtschaticus, through sequential molts in the laboratory

Abstract

Studies of crustacean growth, including king crabs, have typically used modal analysis rather than growth of individual crabs. I studied the individual growth of several hundred juvenile red king crabs (initial size 1435 mm carapace length, CL) that were captured from a pod in Kodiak, Alaska, in July and August 2000, and retained in the laboratory for up to 14 months. During that period, 295 crabs molted at least once, including a subset of 52 that molted twice, and a subset of 9 that molted three times. Mean molt increment (MI) was 5.5 mm, and did not differ significantly between the three molts. MI increased significantly with premolt size for molt 1, and proportional growth rate at molt 1 was greater than that of molts 2 or 3. The first molt occurred earlier (AugustOctober) and at warmer temperatures among smaller crabs than among larger crabs, which molted in JanuaryFebruary at colder temperatures. Post-molt CL for first molts was a simple ratio: Post-molt CL = 1.25·(Pre-molt CL) (R 2 = 0.9587, df = 291). Growth during the second molt was less than during the first molt, possibly reflecting a limitation imposed by the holding conditions. This is the first study to record growth information for individual juvenile red king crabs in the size range of 1550 mm CL through sequential molts, and results can be used to fill a gap in current growth models. © 2012 The Crustacean Society. Published by Koninklijke Brill NV, Leiden.