New Zealand Journal of Marine and Freshwater Research abstracts
Effect of reproductive state and sex on movement and food consumption
of western rock lobster (Panulirus cygnus) in a tank environment
Kris Waddington1
Roy Melville-Smith2
Diana Walker1
Brenton Knott3
1M090 School of Plant Biology
The University of Western Australia
35 Stirling Highway
Crawley
WA 6009, Australia
email: krisw@cyllene.uwa.edu.au
2Western Australian Marine Research Laboratories
Waterman
WA 6920, Australia
3M092 School of Animal Biology
The University of Western Australia
35 Stirling Highway
Crawley
WA 6009, Australia
Abstract The catchability of western rock lobsters (Panulirus
cygnus) during the spawning season (October and November) may be affected
by their reproductive state. In this study, movement and food consumption
of males and females of different reproductive states held in laboratory
tanks were measured as proxies for catchability. Density of lobsters was
found to influence both movement and food consumption. Solitary animals and,
to a lesser extent, two lobsters per tank, were more sedentary and consumed
significantly less food than animals at a density of three or four specimens
per tank. Tests using three animals per tank confirmed that mature, unmated,
and ovigerous females carrying early stage eggs moved more frequently away
from their shelters than males or females carrying late stage eggs (P
< 0.0001, d.f. = 3). Further, unmated females and females with early stage
eggs recorded significantly higher food consumption (P < 0.0061,
d.f. = 3) compared with males or females carrying late stage eggs. The greater
time spent away from shelter and also food consumption make unmated females
and females with early stage eggs likely to be more catchable than males
or females with late stage eggs. As catchability is commonly used to obtain
population estimates from survey data, these results have implications for
surveys which use catch rates of breeding animals as indicators of egg production.
Keywords Panulirus cygnus; western rock lobster;
movement; food consumption; reproductive state; density; catchability
M04071; Online publication date 31 May 2005 Received 31 March 2004; accepted
25 June 2004
New Zealand Journal of Marine and Freshwater Research, 2005, Vol. 39:
365-372
0028-8330/05/3902-0365 © The Royal Society of New Zealand 2005
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