Rabaoui et al.: Life history of Thenus orientalis in the Arabian Gulf 
e Observed catch 
— Predicted catch 
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Figure 5 
Fit of the stock assessment model to observed data on catch of flathead lobsters (Thenus 
orientalis) by large fishing boats, called dhow, from 1995 through 2008 in the waters of 
Saudi Arabia in the Arabian Gulf (top panel). Diagnostic plots for the model are also 
provided (bottom panels). 
K, and M for T. parindicus in Australia (Courtney*) are 
fairly close to those estimated in our study, and L., was 
lower. The K obtained in this study matches that of T: uni- 
maculatus from India (Radhakrishnan et al., 2013), and MW 
reported for the latter was lower than that of this study. 
On the other hand, Hussain (1996) reported higher K and 
M but lower L,, for flathead lobsters in Kuwait. Growth 
modeling was based on just 2 observed cohorts, with the 
juvenile cohort barely represented in the length—frequency 
data. The hierarchical method of inference accounted for 
the different contributions of the 2 cohorts; nevertheless, 
the scant information available for the juvenile cohort 
resulted in an imprecise estimate of K, with an SE almost 
double the value of the estimate (see Table 2). 
There are striking similarities between the life history 
of flathead lobsters and that of the green tiger prawn in 
waters of Saudi Arabia in the Arabian Gulf. The green 
tiger prawn also is a short-lived, fast-growing crustacean 
(Rabaoui et al., 2017). One of the reasons for the fast 
growth of these 2 species could be the effect of tempera- 
ture. Growth rates generally increase with temperature, 
* Courtney, A. J. 2002. The status of Queensland’s Moreton 
Bay bug (Thenus spp.) and Balmain bug (/bacus spp.) stocks. 
Queensland Dep. Prim. Ind., Inf. Ser. QI02100, 18 p. [Available 
from website.] 
but mortality also increases at the highest viable tem- 
peratures (Hartnoll, 1982). Located in an arid climatic 
zone, the western Arabian Gulf has high sea-surface 
temperatures of 36—40°C during summer months, with 
an annual sea-surface temperature of 24°C (Sheppard 
et al., 1992; Al-Abdulkader et al., 2019). There is a south- 
ward increase in temperature due to the greater stag- 
nancy toward the south. Preen (2004) observed average 
monthly sea-surface temperatures <19°C for 4 months in 
Kuwait Bay, but for only 2 months 300 km farther south 
in Ras Tanura, Saudi Arabia, and for only 1 month at the 
southernmost station of Aziziah. This variation in tem- 
perature can be linked with the higher occurrence of flat- 
head lobsters in the northern and central parts of the 
Saudi waters of the Arabian Gulf, indicating avoidance of 
high temperatures by flathead lobsters. In the Mediter- 
ranean Sea, wild slipper lobsters have been reported to 
migrate offshore to avoid the extreme temperatures 
found in shallow waters (Spanier et al., 1988; Spanier 
and Lavalli, 1998). 
Although the availability of fisheries data ends in 
2008, the fact that there has been no directed fishery 
for the flathead lobster since the ban supports the view 
that the results of our analysis presented here are rel- 
evant for the current management of flathead lobster. 
The most remarkable finding pertinent to the potential 
