TIMING OF SPAWNING AND FECUNDITY OF MEDITERRANEAN Siganus rivulatus FORSK

TIMING OF SPAWNING AND FECUNDITY OF
MEDITERRANEAN Siganus rivulatus FORSK.
KH. A. HUSSEIN

Institute of Oceanography and Fisheries, Alexandria, Egypt.

ABSTRACT
The collected samples of S. rivulatus collected during
the period from Hay 1985 to May 1986 in Alexandria region
showed that the onest of spawning starts in June with a
magnitude extending to· september. Spawning was determined
from the gonosomatic index and egg diameter variations.
Fecundity was found to range from 103.2 to 396.6 thousands
for fish length between 15 to 28 cm, and was observed to
be related to total fish length, fish weight and gonad weight.
Diameter of yolked eggs ranged frOlll 0.23 to O.EO RIA, with
an average ot. 0.48 0111. “The frequency of egg diameter showed
that S. rivulatus is a lIlOfIocyclfc fish laying eggs once
a year.