Acid‐base disturbances following exercise in a high‐shore crab,Cyclograpsus lavauxi

Abstract

Abstract Cyclograpsus lavauxi, a high‐shore crab, suffered a marked acidosis after 10 minutes of moderate exercise in air because of increases in haemolymph lactate concentration and PCO2. During recovery in sea water, the levels of lactate and PCO2 decreased rapidly and resting pH was restored within 2 h. In air, lactate was also metabolised rapidly, but PCO2 levels declined more slowly than in water and were partly the reason for the continued depression of haemolymph pH at 24 h. There were discrepancies between the concentrations of lactate anions and metabolic protons in the haemolymph during recovery. Protons were removed more rapidly than lactate anions in sea water, which suggests that branchial excretion of acid, and/or uptake of base, was involved in acid‐base regulation. The metabolic acid load persisted throughout recovery in air and was, despite possible buffering by mobilisation of CaCO3, mainly responsible for the continued depression of haemolymph pH. It is concluded that sea water is neces...