International Journal of Aquaculture, 2018, Vol.8, No.6, 38-42
41
that with the highest fecundity had total length of 17.6 cm and body weight 61.29 g. The relationships between
fecundity and fish length; and fecundity and fish weight are shown in Table 3.
Table 2 Size variation in fecundity of
P. altipinnis
in Ogbese River
Weight of fish (g)
No. of fish
Fecundity range
Average fecundity
20-30
12
1422-4871
3146
31-40
19
492-5118
1986
41-50
22
498-5124
2635
51-60
24
495-5321
2579
61-70
14
1698-6397
5055
Table 3 Relationships between fecundity and other parameters in
P.altipinnis
in Ogbese River
Fecundity versus
n
a
b
r
r
2
Functional equation (F=ax
b
) Significance at 1%
Gonad weight
84
706.9
1,769.0
0.901
0.813
F=706.9(GW)
1,769.0
Significant
Body weight
84
35.4
1,096.0
0.219
0.048
F=35.4(BW)
1,096.0
Not Significant
Total length
84
394.8
3,489.0
0.309
0.096
F=394.8(TL)
3,489.0
Not significant
Gonadosomatic index 84
168.8
376.2
0.612
0.375
F=168.8(GSI)
376.2
Significant
Condition factor
84
-939.7
3,881.0
0.105
0.011
F=-939.7(C.F)
3,881.0
Not significant
Note: n = number of fish, a = intercept, b = slope, r
2
= coefficient of determination, r = correlation coefficient
3 Discussion
The weight of a fish is considered to be function of its length (Zafar et al., 2003). Allen (1938) stated that an ideal
fish maintains dimensional equality, the value of b would be 3.0. A value significantly larger or smaller than 3.0
indicates allometric growth (Tesch, 1978)
The length-weight relationship of
P. altipinnis
showed an increase in weight with a corresponding increase in
length. The value of the regression coefficient (b) is 2.35 which show that the species exhibit negative allometric
growth, they put on weight slower than they increase in length in Ogbese River. This value was similar to the
values reported for some freshwater fish species (Thomas et al., 2003)
The coefficient of determination (r
2
) of 0.75 showed a positive correlation between length and weight of this fish
in the river. The mean condition factor of 1.18 obtained for the population of
P. altipinnis
in Ogbese River was an
indication of the good condition of the fish (Bannister, 1976). Fawole (2002) also reported 1.20 as the mean
condition factor for
M. rume
in Lekki lagoon, Lagos. Mann (1980) stated that GSI is a rough measure of
reproductive effort. Gonadosomatic indices ranged from 0.1 to 2.94% (males) and 4.75 to 40.92% (females) with
mean 0.52%, 14.15% for males and females respectively. The high gonadosomatic indices recorded for both
males (2.94%) and females (40.92%) in the months of August and September, suggests that the possible spawning
period of
P. altipinnis
was during the rainy season, which is in agreement with Konan et al. (2014). The species
was found to be of high fecundity which ranged between 492-6397 eggs per fish. The correlation coefficient (r),
between fecundity and gonad weight (0.90); fecundity and GSI (0.61), were significant (
p
<0.05). This study has
shown that there were wide variations in the fecundity of
P. altipinnis
, Fawole and Adewoye (1999) attributed
these wide fluctuations to differential feeding success within members of the fish population. From the result of
this study,
P. altipinnis
was in good condition and highly fecund, thus a potential candidate for aquaculture
production to meet the high demand for fish in Nigeria.
Acknowledgements
I wish to express my gratitude to Mr. A. Adejuyigbe of the Department of Animal and Environmental Biology, Adekunle Ajasin
University, Akungba- Akoko, Nigeria for his assistance in the collection of specimens.
References
Abowei J.F.N., 2010, The condition factor, length-weight relationship and abundance of
Ilisha africana
(Block 1795) from Nkoro River, Niger Delta, Nigeria,
Advanced Journal of Food Science and Technology, 2(1): 6-11
