Circulatory, respiratory and metabolic response to emersion and low temperature of Jasus edwardsii: simulation studies of commercial shipping methods

The Southern Rock Lobster Jasus edwardsii is a commercial species. The resp iratory and metabolic response of J. edwardsii during simulated commercial handling was investigated. Lobsters were dipped in 5 degrees C seawater for 2 min and exposed to air for up to 30 h in shipping cases containing ice ( chilled), or packed without chilling. Controls were immersed at 18 degrees C. Chilling ameliorated tachycardia and hyperventilation caused by the pack ing process. Non-chilled J. edwardsii accumulate an O-2 deficit but chillin g lobsters delayed anaerobiosis for up to a day. Haemolymph urate accumulat ed only in non-chilled lobsters, indicative of a rapid tissue hypoxia. The muscle ATP concentration of J. edwardsii in air decreased, regardless of ch illing, with a corresponding loss of energy charge. A hyperglycaemia in eme rsed J. edwardsii was accompanied by decreased glycogen stores in chilled l obsters. The low IMP concentration in chilled J. edwardsii shows that 30-h emersion stress probably does not compromise taste and value of the lobster s. Chilling extends shipping time and distance, so after 10 or 30 h in tran sit, the lobsters are largely aerobic. When the chilled lobsters reach thei r destination after 30 h, accumulated IMP and inosine, and decreased glycog en, may have a significant effect on taste. Recovery is important before co oking if a fresh flavour is desired. (C) 1999 Published by Elsevier Science Inc. All rights reserved.