Respiration of a low oxygen tolerant galatheid crab, Munida quadrispina (Benedict, 1902)

Publisher Website
Google Scholar
Abstract
A recent study on Munida quadrispina in the cliff community of Saanich Inlet, an intermittently anoxic fjord, showed that these crabs have a size distribution corresponding to the vertical oxygen gradient. This study tested the hypothesis that the size gradient was caused by a size-dependent respiratory tolerance. The factor used for comparison was Pc (critical oxygen concentration below which the rate of oxygen consumption declines). Size specific Pc was compared with habitat oxygen levels at which different sized animals were captured in Saanich Inlet. Regulated oxygen consumption and Pc decreased significantly (p < 0.01) with increasing wet weight of crabs. Pc decreased significantly (p < 0.01) as carapace length increased. The slope and elevation of the latter relationship were not significantly different (p < 0.01, ANCOVA) from the slope and elevation of the relationship of carapace length versus habitat oxygen. This observation is consistent with the hypothesis that the vertical size gradient in Saanich Inlet is related to a size-specific Pc. The minimum Pc observed (0.14 mL oxygen/L) corresponded with the lowest oxygen levels at which crabs were found in Saanich Inlet (0.1–0.15 mL oxygen/L).