REPRODUCTIVE BIOLOGY, SPERMATOGENESIS AND ULTRASTRUCTURE OF TESTES CARANX CRYSOS (MITCHILL,1815)

REPRODUCTIVE BIOLOGY, SPERMATOGENESIS AND
ULTRASTRUCTURE OF TESTES CARANX CRYSOS
(MITCHILL,1815)
BY
SAMIRA, S. A.SSEM*
*National Institute OJOceanography and Fisheries, Alexandria
Key words: Carangidae, Caranx crysos, reproductive biology. spermatogenesis~
Ultrastructure.
ABSTRACT
The maturity stages of Caranx crysos can be classified into six
stages, as the fish have a long spawningperiod extendingfrom May
to early Naven-the,.. All males over 19 cm in length are sexualiy
mature. The gonadosomatic index (OSI) increased progressive{v
towards the spawning season. The peak value was attained in June
then GSI decreased gradually from August to October. The
,’lpemlatogenic activity in Caranx crysos started in April andMay.
Throughout the period from June to October the testes were in the
ripe and spawning stages. From November to late .lv/arch most ofthe
iestes were in the spent and recovery stages. During trl£ spent and
recovery periods the spermatogenesis passed through a period of
quiescent. Using the ultrastructural analysis, large spermatogonia
were characterized by faintly stained cytoplasm. Their nucleus were
homogenous in appearance. In Caranx crysos the fine strocture of
nuclei in the primal}’ and secondary spermatocytes had a thick
clumped chromatin and a thin layer of cytoplasm. The nucleus in
spermatid cell had condensed chromatin materials. As in most
teleosts the motile sperm was characterized by three regions (head,
midpiece and tail).