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Fishery Bulletin 107(1) 
commercially important species of scale fish on the 
south coast of Western Australia and is highly regarded 
by recreational anglers, detailed studies of its biology 
have been restricted to its foraging behavior, diet, and 
habitat, and how these change with body size (Shep- 
herd, 2005; Shepherd and Brook, 2007). In contrast, 
several aspects of the biology of the congeneric eastern 
blue groper ( Achoerodus viridis), which is distributed 
along the eastern and southeastern coasts of Australia 
and does not grow to as large a size as that of A. gouldii 
(Hutchins and Swainston, 1986), have been studied 
(e.g., Gillanders, 1995a, 1995b, 1997; Gillanders and 
Kingsford, 1998). The apparently detrimental effects of 
fishing on A. viridis led to this species being protected 
from both recreational and commercial fishing in 1969, 
although these restrictions were later eased to some 
extent in 1974 (Gillanders, 1999). 
The present study demonstrates that A. gouldii is 
a protogynous hermaphrodite and provides data on 
the length and age compositions, growth, reproductive 
biology, recruitment variability, and stock status (mor- 
tality, and spawning potential ratio) of this species in 
southwestern Australian waters. The data were used 
to test the following hypotheses. 1) The far greater size 
of A. gouldii than the morphologically and ecologically 
similar congeneric eastern blue groper ( Achoerodus viri- 
dis) is reflected in a greater maximum age and greater 
sizes and ages at which females become mature and 
later change sex. 2) It would then follow that A. goul- 
dii has by the greatest longevity of any labrid species. 
Because protogynous labrids that exhibit sexual dichro- 
matism tend to change color at about the same size and 
age as at which sex change occurs, the body colors of A. 
gouldii (typically green for females and blue for males) 
can be used as proxies for sex for determining the total 
length at which 50% of fish <TL 50 ) change color and the 
patterns of growth of females and males of this labrid. 
An ability to use color in this manner would be useful 
when, for example, fish cannot be dissected or the vis- 
cera have been removed. 3) Because environmental fac- 
tors on the southwest coast of Australia, such as those 
brought about by marked variations in the strength 
of the Leeuwin Current (Pearce and Phillips, 1988), 
exhibit considerable interannual variations in winter, 
i.e., when A. gouldii spawns (see Results section), the 
recruitment success of this species on this coast differs 
among years. Lastly, inferences drawn from the biologi- 
cal data and stock assessment parameters are discussed 
for their applicability to management plans aimed at 
conserving the stocks of A. gouldii. 
Materials and methods 
Sampling regime and laboratory processing 
Achoerodus gouldii was collected monthly or bimonthly 
between April 2004 and October 2007 from numerous 
sites in coastal waters between Albany (at 35°01'S, 
117°58'E) and Esperance (at 33°45'S, 21°55'E) off the 
south coast of Western Australia. These fish were either 
caught by spear fishing in shallow (<20 m) inshore 
coastal waters or were obtained from commercial gill 
net fishing crews (mesh range=165-178 mm) operating 
in deeper (-20-100 m) offshore waters. A few A. gouldii 
(-3%) were also collected directly from commercial gill- 
net fishing vessels fishing in deeper, offshore waters at 
a latitude of ~32°S on the lower west coast of Australia. 
Although many of the individuals obtained from commer- 
cial gillnet fishing vessels were supplied as eviscerated 
and filleted frames, some were intact and therefore still 
contained their gonads. 
Shallow, inshore water temperatures at Albany 
and Esperance, recorded by the Department of Fish- 
eries, Western Australia, at intervals in the years 
1994-2006, were pooled by month and used to cal- 
culate the average for each calendar month. Mean 
monthly offshore sea surface temperatures for Albany 
and Esperance in 2004-06 were derived by using a 
combination of data from National Oceanic and Atmo- 
spheric Administration (NOAA) advanced very high 
resolution radiometer (AVHRR) satellite imagery and 
from sea surface temperatures recorded by shipping 
and drifting buoys (Reynolds and Smith, 1994). The 
mean monthly water temperatures in inshore and off- 
shore waters in the above two main sampling locations 
were plotted to elucidate the relationship between 
the initiation and duration of spawning and water 
temperature, which are typically related in teleosts 
(e.g., Lam, 1983). 
The color (green or blue) and total length (TL, to 
the nearest 1 mm) of all A. gouldii, and the wet weight 
(W, to the nearest 0.1 g) of each of those individuals 
that had not been filleted, eviscerated, (or both), were 
recorded. The sex of each A. gouldii that had not been 
eviscerated and had a TL >-100 mm (the length above 
which the sex could be determined macroscopically) 
was also recorded. Because all of the large number of 
sexed fish <655 mm were females (see Results), the 
small number of fish <100 mm were recorded as this 
sex. Although the possibility cannot be excluded that 
some of the latter very small A. gouldii (<100 mm) may 
have been bisexual (i.e., possessed gonads containing 
both ovarian and testicular material), the fact that all 
individuals between the substantial length range of 
100-655 mm were females means that this attribute 
would not have influenced the conclusions regarding 
whether this species is hermaphroditic and, if so, of 
which type (see Discussion). The gonads of each fish 
were removed and weighed to the nearest 0.01 g. 
The relationship between TL and W was used to es- 
timate the weights of A. gouldii collected from fish 
processors and recreational fishing crews and which had 
been filleted, eviscerated, or both, before they could be 
weighed. To facilitate comparisons between the lengths 
of A. gouldii and those of its congener A. viridis, the lat- 
ter of which were recorded as standard lengths to the 
nearest 1 mm by Gillanders (1995a), standard lengths 
for 455 A. viridis were converted to total lengths by 
using the equation 
