Respiratory gas transport, haemocyanin function and acid-base balance in Jasus edwardsii during emersion and chilling: simulation studies of commercial shipping methods

The Southern Rock Lobster Jasus edwardsii is a commercial species often shi pped in air. Respiratory gas transport, haemocyanin function and acid-base balance were assessed during emersion and emersion with chilling; i.e. redu ced packing and shipping temperature. The affinity of the haemocyanin (Hc) for O-2 was low (P-50 - 3.44 kPa, 20 degrees C) but was increased by urate and Ca but not L-lactate. Chilling from 25 to 5 degrees C increased Hc-O-2 affinity (Delta H = 36.6 kJ mol(-1) at pH 7.4) and reduced the Bohr shift f rom phi = - 0.2 to - 0.09. In air, non-chilled lobsters became acidotic whi le chilling induced an alkalosis. The haemolymph P-o2 of non-chilled J. edw ardsii in air decreased and the a - v P-o2 difference declined, prompting i mmediate anaerobiosis. Chilling J. edwardsii lowered metabolism and maintai ned P-ao2 for up to 5 h in air. Thereafter, emersion depleted the venous O- 2 reserve. In non-chilled lobsters a urate-induced increase in Hc-O-2 affin ity appeared important but these lobsters were unable to maintain respirati on adequately and were reliant on anaerobiosis. As the chilled lobsters war med they were unable to load adequate O-2 and the venous reserve became dep leted. Oxygen transport and respiration were assisted by increased haemolym ph urate, and together with chilling enabled O-2 uptake and transport to me et demand for 30 h in air. (C) 1999 Elsevier Science Inc. All rights reserv ed.