ANAEROBIC METABOLISM DURING ANOXIA IN THE BURROWING SHRIMP CALOCARIS-MACANDREAE BELL (CRUSTACEA, THALASSINIDEA)

The thalassinidean shrimp Calocaris macandreae inhabits complex burrow s in marine muddy sediments which are subject to severe hypoxia. In th e laboratory, C. macandreae was highly tolerant of anoxia (LT(50) = 43 hr) and accumulated L-lactate as the major end-product of anaerobic m etabolism. Metabolic recovery of C. macandreae from anoxia was slow; h aemolymph lactate concentrations returned to normal levels after appro ximately 40 hr. Anaerobic metabolism appeared to be initiated only dur ing exposure to severe hypoxia (PO2 < 7 Torr).