Reproductive Biology of Kingsoldier Bream (Argyrops spinifer) in the Persian Gulf

Iranian Scientific Fisheries Journal, Vol. 26, No.3.

Abstract:

The reproductive characteristics of 639 specimens of kingsoldier bream, Argyrops spinifer, a
commercial species of Sparidae family in the Persian Gulf were investigated by monthly sampling
during June 2010 to May 2011. Samples were caught by local fisherman using trawl net in waters of
Bushehr province. Each month, a total of 50-60 specimens of fish were examined, on average. Total
length ranged from 15-61 (24±6.6) cm in males and 13-64 (24.0±7.9) cm in females and total weight
ranged 77-3450 (323.6±319) g and 52-4162 (370±465) g in males and females, respectively. Total
length (Lm50) and age (Am50) at first maturity were estimated as 30 cm and 5 years for males and 31
cm and 6 years for females, this indicate that A. spinifer is exploited below the mean size at sexual
maturity. The overall sex ratio was 1.25F:1M and were significantly different from the expected ratio
(p<0.05). The highest value of condition factor was observed in January for females and in February
for males. The minimum, maximum and average absolute fecundity were 79000, 2375000 and
683000±528000, respectively for females 17-47 cm total length and weighing 117-1666 g. The
relationship between absolute fecundity and fish total length was represented by the following linear
equation: F= 54417L–92699 (r= 0.77), and a linear equation: F= 1165W+41595 (r= 0.81) was found
between absolute fecundity and fish weight. The analysis of ova diameter for the species revealed that
there are three egg batches in ripe ovary of A. spinifer and swing diameter of eggs in the ovaries of
these fish throughout the year, was between 25-800 microns. Regarding gonado-somatic index (GSI)
values, oocyte diameter, histological studies and abundance of different stages of maturity at different
month, it seems that spawning of A. spinifer occurs from December to April. Indeed, gonad maturation
started from December and spawning completed in March and April. Long spawning season suggests
that A. spinifer is a multiple spawner with an asynchronous ovary. This finding could be confirmed by
oocyte diameter and histological studies, too. The results of the present study presume state of both
protogyny and rudimentary hermaphroditism in A. spinifer.