Fish Spawning Season Analysis
Table 1. Degree of maturation and the morphology of the gonad in different stages
of maturity of O.mossambicus
Stage
Degree of maturation
Immature or virgin
and resting adult
Months of
availability
Throughout
the year
II
Early maturing
March to
September
III
Developing
March to
October
IV
Developed /
pre spawning
March to
October
Ova diameter
(mm)
0.045 0.055
0.056 -0.090
0.091-0.85
0.86 0.99
Spawning
April to
October
1.0 1.5
VI
Spent
April to
late
October
0.052 0.17
Description of the gonads
Ovaries very small, thin, thread like pale in
colour, occupying a small part of the body
cavity. Testes is thin, slender translucent
and pale in colour. Both the gonad invisible
to the naked eye.
Ovaries become slightly larger and increase
in weight and volume with minute opaque
whitish eggs occupied about half of the
body cavity. Testes become enlarge, flat,
increase in weight and volume, and creamy
white in colour. Both the gonad are readily
seen without any aid.
Ovaries distended occupied, about 2/3 of
abdominal cavity with large pale yellow
eggs. Testes enlarge, increase in weight and
volume, light pinkish and thicker in size and
look more vascular. Blood capillaries
become conspicuous.
Ovary becomes more enlarged occupying
almost entire body cavity, with large
number of big, turgid, spherical, translucent,
deep yellow riped ova. Testes become soft
turgid pinkish red and increase in weight
and volume. Blood capillaries prominent.
Roe to milt run with slight pressure.
Ovary walls become thin almost
transparent. Riped eggs are visible through
the ovarian wall and some riped eggs are
present in the oviduct. Testes become
flabby, thin and dull white in colour.
Gonad shrunken having loose walls.
Ovaries are flaccid, shrinked and sac like,
reduced in volume. Ovary contains ripped
unspawned darkened eggs and a large
number of small ova. Testes become flabby,
thin and dull white in colour.View entire presentation