New Zealand Journal of Marine and Freshwater Research abstracts
Predicting survival of western rock lobsters Panulirus cygnususing
discriminant analysis of haemolymph parameters taken immediately following
simulated handling treatments
B. D. Paterson1
P. T. Spanoghe1,2
G. W. Davidson1,2
W. Hosking3
S. Nottingham1
J. Jussila4
L. H. Evans4
1Centre for Food Technology
Queensland Department of Primary Industries & Fisheries
19 Hercules St, Hamilton
QLD 4007, Australia
email: Brian.Paterson@dpi.qld.gov.au
2School of Biomedical Sciences
Curtin University of Technology
GPO Box U 1987 Perth
WA 6001, Australia
3Geraldton Fishermen’s Cooperative
P.O. Box 23, Geraldton
WA 6531, Australia
4Aquatic Science Research Unit
Curtin University of Technology
GPO Box U 1987 Perth
WA 6001, Australia
Abstract Instances of morbidity amongst rock lobsters
(Panulirus cygnus) arriving at factories in Western Australia (WA)
have been attributed to stress during post-harvest handling. This study used
discriminant analysis to determine whether physiological correlates of stress
following a period of simulated post-harvest handling had any validity as
predictors of future rejection or morbidity of western rock lobsters. Groups
of 230 western rock lobsters were stored for 6 h in five environments (submerged/flowing
sea water, submerged/recirculating sea water, humid air, flowing seawater
spray, and recirculated seawater spray). The experiment was conducted in late
spring (ambient sea water 22°C), and repeated again in early autumn (ambient
sea water 26°C). After 6 h treatment, each lobster was graded for acceptability
for live export, numbered, and its haemolymph was sampled. The samples were
analysed for a number of physiological and health status parameters. The
lobsters were then stored for a week in tanks in the live lobster factory
to record mortality. The mortality of lobsters in the factory was associated
with earlier deviations in haemolymph parameters as they emerged from the
storage treatments. Discriminant analysis (DA) of the haemolymph assays enabled
the fate of 80–90% of the lobsters to be correctly categorised within each
experiment. However, functions derived from one experiment were less accurate
at predicting mortality when applied to the other experiments. One of the
reasons for this was the higher mortality and the more severe patho-physiological
changes observed in lobsters stored in humid air or sprays at the higher
temperature. The analysis identified lactate accumulation during emersion
and associated physiological and haemocyte-related effects as a major correlate
of mortality. Reducing these deviations, for example by submerged transport,
is expected to ensure high levels of survival. None of the indicators tested
predicted mortality with total accuracy. The simplest and most accurate means
of comparing emersed treatments was to count the mortality afterwards.
Keywords mortality; live storage; stress; rock lobster;
lactate; anaerobiosis
M04061; Online publication date 16 August 2005 Received 30 March 2004;
accepted 19 July 2005
New Zealand Journal of Marine and Freshwater Research, 2005, Vol. 39:
1129–1143
0028-8330/05/3905-1129 © The Royal Society of New Zealand 2005
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