REPRODUCTIVE BIOLOGY OF THE GIANT CLAM TRIDACNA MAXIMA (BIVALVIA: TRIDACNIDAE) IN THE NORTHERN RED SEA

REPRODUCTIVE BIOLOGY OF THE GIANT CLAM TRIDACNA

MAXIMA (BIVALVIA: TRIDACNIDAE) IN THE NORTHERN

RED SEA

By
R. KILADA*; S. ZAKARIA AND M. MOHALLEL
*Suez Canal University, Faculty o/Science, Dept 0/Marine Science. lsmailia-Egypt.
Key Words: giant clams, Tridacna, Tridacnidae, Bivalvia, Red Sea.
ABSTRACT
Giant clams I1re the biggest bivalves ever exist and are confined to
the Indo-Pacific area. Tridacnid clams are protandrous
hermaphrodite, thu~ the anim111 starts its l{fe as male and becomes
somatic
simultaneous
Index
hermaphrodite
reached its ma-rimum
at sexual
value
maturity
in May
age.
(46)
The
and
Gonadothen it
dropped in June (20). The change in the GSI values indicated that
spawning might have happened at that time. This was supported by
histological examination to the clam gonad over one year. Ripe
animals were found in early summer months and spent individuals
were in summer time. Deposition ofsperm and ova were synchronized
and was shown by comparing the reproductive scores of both
gametes. Finally. the mznimum size of sexual maturity was 8 cm at
which some individuals were nuticed fo be hermaphrodite.