Reproduction Food Length -weight Relationship And Condition Factor Of African Catfish Clarias Gariepinus (burchell) In Lake Babogaya Ethiopia

Some aspects of reproduction, food and feeding habits as well as length weight relationshiprnand condition of Clarias gariepinus in Lake Babogaya were studied at Lake Babogayarnlocated in the vicinity of Bishoftu town at about 45 Km East of Addis Ababa. Samples ofrnC.gariepinus were collected monthly during September (2005) through to August (2006)rnusing hook - and - line method and gillnets of various mesh sizes. Sex ratio was notrnsignificantly different from 1:1 except in samples taken in April and July, and in lengthrngroups between 25 and 54 cm total length (TL) in the total sample. In all these cases, therernwas a preponderance of females over males. In the total sample, for instance, females werernabout 1.26 more numerous than males. The 50% sexual maturity length (L50) was estimatedrnat 50 cm TL for females and 56 cm TL for males. Estimated fecundity, which was linearlyrnrelated with fish and gonad sizes ranged from 398 to 1165 eggs per gram with a mean of 945.rnAbsolute fecundity was estimated to range from 11,000 to 580,571 with a mean of 159,660.rnGonadosomatic index and frequency of ripe gonads suggested that C. gariepinus inrnBabogaya breeds throughout the year with intensive breeding activity during March to Julyrnand less intensively in September. Intensive breeding was coincident with the rainy seasons.rnC. gariepinus was found to ingest a variety of organisms of plant and animal origins, as wellrnas items including detritus and sand grains. However, insects, zooplankton and fishrn(Oreochromis niloticus) were found to be the most important food of C. gariepinus inrnBabogaya. Thus, the fish is considered to have a mainly carnivorous feeding habit. The majorrnfood items ingested were all size groups of the fish during all sampling months of the study.rnHowever, the importance of insects and zooplankton tended to decrease whereas that of fish tended to increase with the TL of C. gariepinus. Thus, it appeared that the fish feedsrnprogressively more O. niloticus as it grows larger. However, based on predator to prey sizernratio of which 85 % range between 1:5 to 1:30, there was no direct correlation between thernsize of C. gariepinus (predator) and that of its prey (O. niloticus). High incidence of emptyrnstomachs was observed during the whole sampling period. But, the frequency of emptyrnstomach was high during the rainy season, which could be associated with breeding activity.rnThe contribution of insects and zooplankton to the diet of C. gariepinus was relativelyrnhighest towards the end of the main rainy season, whereas the contribution of O. niloticusrnwas relatively high during the rainy season. The relationship between total length (25 to 102rncm) and total weight (165 to 7000 g) was curvilinear and represented as TW = 0.0156rnTL2.934, R2 = 0.942, P < 0.05. Fulton condition factor (mean ± SE) was 0.66 ± 0.04 forrnfemales, 0.63± 0.03 for males and 0.64 ± 0.01 combined for both sexes.rnKey Words/Phrases: Lake Babogaya, C. gariepinus, Reproduction, Food, length weightrnrelation, condition factor, Ethiopia

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