Coulson and Poad: Biological characteristics of Psettodes erume/ from the Indian Ocean 
Total length (mm) 
E 
E 
< 
= 
D 
< 
2 
o 
cS) 
Fk 
6 
Total length (mm) 
8 
175 
10 
Age (years) 
Figure 5 
von Bertalanffy growth curves fit to total lengths at age for (A) female and (B) male Indian halibut (Psettodes erumet) 
caught by commercial trawlers in February 2014—December 2015 and during research surveys in August 2015-September 
2017 off the Pilbara coast in northwestern Australia. Samples sizes (n) are given for each graph. (C) Comparisons of 
growth curves fit to the lengths at age of female (F) and male (M) Indian halibut from northwestern Australia (solid black 
lines) and from the northwestern Bay of Bengal (dotted black lines) (Das and Mishra, 1990) and of growth curves fit to 
the lengths at age of females and males combined from Brunei (dotted gray line) (Silvestre and Garces, 2004), the Gulf of 
Aden (dashed gray line) (Edwards and Shaher, 1997), and the Persian Gulf (dashed black line) (Gilanshahi et al., 2012). 
Growth curves from Gilanshahi et al. (2012) and Silvestre and Garces (2004) were derived from trends in monthly length 
frequencies, and curves from Das and Mishra (1990) and Edwards and Shaher (1997) are based on individual fish aged 
by using whole otoliths and vertebrate, respectively. 
testes (stages 5 and 6) largely dominated samples col- 
lected between September and February. 
Although the prevalence of female and male Indian hal- 
ibut with gonads at stages 5-8 between September and 
February increased, the abundance of individuals with 
gonads at stages 3 and 4 declined markedly or were not even 
present. Still, female and male Indian halibut with gonads 
at stages 3 and 4 more than likely become mature during 
the spawning season. Therefore, fish with gonads at stages 3 
and 4 and at stages 5-8 were collectively regarded as mature 
for the purposes of estimating length and age at maturity. 
Trends in the GSIs and prevalences of females and males 
