Gonadosomatic index, fecundity and egg size of (Synodontis) S. eupterus (Boulenger) in River Rima, north western Nigeria
This study was conducted to provide information on gonadosomatic index, fecundity and egg size on S. eupterus from River Rima, North-Western Nigeria, from November 2005 and December 2008. 1,610 samples, comprising of 781 females, 816 males and 13 samples whose sexes could not be identified were examined, giving a female: male ratio of almost 1:1. Gonadosomatic index (GSI), fecundity (F) and diameter of the oocytes (ES) were analysed. Linear regression analysis was used to determine the relationship between GSI, fecundity and egg size with total length (TL), total weight (TW), gonad weight (GW) and gonad maturation stages (MS). Six stages of gonad maturation were established. Mean GSI for female and males were 7.30 0~c6.16SD and 1.05~c1.23SD, respectively. It varied (P< 0.05) with sex, size class and gonad maturation stage, and exhibited significant (P<0.05) correlation with fish TL, TW and MS in females but not (P>0.05) in males. Mean fecundity was 2834.45~c2530.87SD and it correlated most significantly (P<0.05) with GW; and inversely with MS. Mean egg size was 1.31~c0.33mm. It has non significant (P>0.05) relationship with TL, TW and MS but significant one (P<0.05) with GW. Egg size distribution was bimodal, with different sizes of egg in ovaries indicating multiple spawning. This study provided baseline information on some aspects of reproduction which is important in the management of A. occidentalis in River Rima.
| Main Authors: | , |
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| Format: | conference_item biblioteca |
| Language: | English |
| Published: |
FISON
2012
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| Subjects: | Ecology, Fisheries, S. eupterus, A. occidentalis, Nigeria, Rima R., Gonadosomatic index, fecundity, oocyte diameter, gonad maturation stage, S.eupterus, freshwater environment, Fecundity, Fish eggs, Size, Reproduction, Fish, Spawning, Frequency, Oocytes, |
| Online Access: | http://hdl.handle.net/1834/38783 |
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