International Journal of Aquaculture, 2018, Vol.8, No.6, 38-42
40
using the formula:
2 Results
2.1 Length-weight relationship
The total lengths of 240 specimens of
P. altipinnis
examined in this study ranged from 12.6 to 18.8 cm while the
weights ranged from 28.00 to 76.20 g. Figure 2 illustrates the length-weight relationship of the species. Table 1
presents the length-weight regression analysis of the species. Relationship between total length and body weight
of all the specimens were estimated as:
，
Figure 2 Length-weight relationship of
P. altipinnis
(combined sexes) in Ogbese River, Southwest, Nigeria
2.2 Condition factor
The condition factor (K) value was calculated for
P. altipinnis
. The condition factor (K) for male ranged from
0.87 to 1.41 while in females it ranged from 0.85 to 1.74 and the mean condition factor for male, female and
combined sexes were 1.17, 1.19 and 1.18, respectively (Table 1).
Table 1 Condition factor and Length-weight relationships of
P
.
altipinnis
in Ogbese River, Southwest, Nigeria
Sex
No.
TL (range)
W(range)
Mean K
a
b
r
2
Female
124
12.8-18.4
28.01-72.12
1.19
-1.13
2.33
0.74
Male
116
13.2-18.5
31.94-75.87
1.17
-1.21
2.39
0.78
Combined
240
12.8-18.5
28.01-75.87
1.18
-1.15
2.35
0.75
2.3 Sex ratio
The results showed that of the 240 specimens examined 116 were males and 124 were females giving a sex ratio
of 1:1.07.
2.4 Gonadosomatic index (GSI) and fecundity
The gonad weight expressed as a percentage of the fish body was used as the gonadosomatic index (GSI). The
GSI for male ranged from 0.12 to 2.94 while that of the females ranged from 4.75 to 40.92. The mean GSI for
male was 0.52 while 14.15 was for females. In Table 2, fecundity ranged from 492 eggs (14.5 cm) to 6397 eggs
(17.6 cm). The fish specimen with the lowest fecundity has a total length of 14.5 cm and body weight 33.2 g while
y = 2.3555x - 1.1595
R²= 0.7582
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
1.05
1.1
1.15
1.2
1.25
1.3
Logarithm of the weight
Logarithm of the length
