Advanced live lobster transport: effects of the anaesthetic AQUI-S on cardiac physiology of Jasus edwardsii

Abstract

Lobsters are highly valuable species of crustacean, often being transported live over great distances. This is done to capitalise on the high prices they fetch in some international markets, where high quality, live individuals are valued at over a US$100 per kg. Lobsters experience significant mechanical and environmental stressors as part of the transport process, which initiate physiological responses that compromise their health and value at market. Metabolic suppressants, such as anaesthetics, can inhibit awareness of stressors, preventing detrimental physiological responses. As such, anaesthetics are utilized in a variety of vertebrate species to preserve the health and promote recovery of individuals exposed to stressful procedures. AQUI-S, an effective aquatic anaesthetic regularly used in handling of live seafood, was selected for evaluation as a potential metabolic suppressant in live lobsters to improve the physiological outcomes for live lobster transport. Using a non-invasive heart monitoring technique, the response of cardiac physiology (BPM) in the Australasian rock lobster Jasus edwardsii was examined when exposed to increasing concentrations of AQUI-S, and compared with heart rate response to standard transport procedures. Heart rate changed significantly with induction of AQUI-S, rising above standard transport heart rates at low concentrations, and falling below at higher concentrations. An experimental dose (200 ppm) was selected for comparative evaluation of metabolic suppression to; 1) standard AQUI-S concentrations (40 ppm), and 2) the standard commercial method of ‘cold anaesthesia’ (~5 °C seawater), during simulated live transport. Heart rate and standard physiological responses in lobsters anaesthetised using AQUI-S were not significantly different to commercial methods during the course of simulated transport, and appeared to impart a greater degree of sensory suppression and metabolic conservation with increasing dose concentration. Metabolic suppression was confirmed with in situ assessment of cardiac mitochondrial response to AQUI-S. Isolation and induction of cardiac mitochondria resulted in significant inhibition of respiration, occurring at complexes I, III and IV, indicating mitochondrial suppression as a potential mechanism of action for AQUI-S. While the results of this study demonstrate that AQUI-S can conserve metabolic rate during live lobster transport, the rapid withdrawal time indicates concentrations approaching the safety margin are necessary to achieve commercially relevant benefits.