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vol-11REPRODUCTIVE CYCLE OF MALE SIGANUS RIVULATUS FORSK.
WITH INDICATION TO GONOSOMATIC AND
HEPATOSOMATIC INDICES.
E.M. AMIN
Institute of Oceanography and Fisheries, Alexandria, Egypt.
ABSTRACT
Studied samples of Siganus rivulatus were obtained from the
commercial catch of Red Sea (Jeddah, ~audi Arabia). The testicular
development of male S. rivulatus started early in this subtropical
area and firmly affected by the significant elevation of water
temperature. Histologically examined testes showed an active
spermatogenses in February, and spawning season extended from March
to Septl!mber. Spent ma 1es sti 11 possessed remnants of not shedded
spermatozoa distributed in the empty testicular tubules and sperm
duct. A gradual resorption of such being left spermatozoa took
place as a result of phagocytic activities. Determined values of
GSI gave a further confirmation to the time of spawning. The increase
was towards the more developed testes. whence the beginning of
spawning. Values of HSI were extremely decreased as the testes
became matured, and significantly increased after spawning and
before the onset of a new sexual cycle.
