Settlement, substratum preference, and survival of red king crab Paralithodes camtschaticus (Tilesius, 1815) glaucothoe on natural substrata in the laboratory

Abstract

Preferences of red king crab (RKC) Paralithodes camtschaticus glaucothoes for a variety of live substrata were tested in the laboratory. Recently molted glaucothoes settled immediately on all substrata except a bare control tank. Preferred substrata (in decreasing order) were hydroids, algae, other (airstones, tank bottom), sand and worms, and did not change much until after molting to stage C1 at day 30. Survival to stage C1 was highest (93%) in the control tank, least (18%) on sand and intermediate (53–60%) on other substrata. Red king crab glaucothoes demonstrate similar preferences for structurally complex biological substrata in the laboratory as they do in the wild. Settlement on sand occurs only as a last resort and results in higher mortality. These results indicate the importance to settling larvae of biogenic oases that may be easily disturbed by hard-on-bottom fishing activities, and underscore the importance of conserving such habitats. Furthermore, knowledge of settlement, habitat selection and substratum preference are essential prior to considering the potential of king crabs for stock enhancement or aquaculture.