Effects of emersion on the haemolymph metabolites of the Japanese lobster, Panulirus japonicus (Decapoda, Palinuridea)

Abstract

Haemolymph protein, ammonia, urea, urate, glucose. L-lactate, osmolality, ion concentrations and acid-base balance were measured when Japanese lobster Panulirus japonicus were exposed to air at 5, 15, and 25degreesC for 3 h up to 48 h. All lobsters in aerial exposure at 5 and 15degreesC survived after 48 h, whereas 60% of the lobsters survived at 25degreesC after 24 h. Haemolymph haemocyanin, protein, pCO(2), ammonia. urea, urate, L-lactate, osmolality, Cl-, Ca2+, and Mg2+ increased linearly with exposure time. However, haemolymph pH and glucose were inversely related to exposure time. Lobsters in aerial exposure at 5 and 15degreesC significantly increased their HCO3-, whereas lobsters in aerial exposure at 25degreesC decreased their haemolymph HCO3-. Lobsters in 24 h aerial exposure at 25degreesC increased their haemolymph ammonia, urea, and L-lactate, respectively more than 8, 3 and 572 times, whereas lobsters in 24 h aerial exposure at PC increased to 7, 2, and 275 times of submerged values, The ability of P. japonicus to survive longer at low temperatures (5 and 15degreesC) is likely due to lower accumulation of ammonia, urea, urate, and L-lactate, and buffering due to HCO3-.