Respiratory responses of the pea crab, Pinnotheres hickmani (Guiler)

Abstract

The respiration rates for various developmental stages of the Australian pea crab, P. hickmani, were obtained at three temperatures, representing the normal environmental range, and in light and dark conditions. The free-living hard stages of both the males and the females, show marked variation in oxygen uptake compared with the pre- and post-hard commensal stages. Oxygen requirements increase as the female matures to the stage-V form. Results obtained indicate that, under normal conditions, the presence of P. hickmani within a host mussel, Mytilus edulis planulatus, would present no undue burden on the host's available oxygen. Under conditions of low oxygen tension, P. hickmani shows the ability to build up an oxygen debt, again providing no undue burden on its host. It is proposed that P. hickmani is an obligatory commensal within M. e. planulatus.