Frontiers in Science
p-ISSN: 2166-6083 e-ISSN: 2166-6113
2013; 3(4): 107-113
doi:10.5923/j.fs.20130304.01
N. Kasozi1, G. I. Degu1, K. Atibuni1, M. Kisekka2, A. Owori-Wadunde3, S. Mugerwa4
1Livestock and Fisheries programme, Abi Zonal Agricultural Research and Development Institute, P.O. Box 219, Arua-Uganda
2Department of Veterinary Pharmacy, Clinics and Comparative Medicine-Makerere University: P.O Box 7062 Kampala-Uganda
3Aquaculture Research and Development Center (ARDC), Kajjansi. P. O. Box 530 Kampala-Uganda
4National Livestock Resources Research Institute, P. O. Box 96, Tororo-Uganda
Correspondence to: N. Kasozi, Livestock and Fisheries programme, Abi Zonal Agricultural Research and Development Institute, P.O. Box 219, Arua-Uganda.
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The indigenous Alestes baremoze is one of the fishes endemic to Lake Albert. In this study, the maturity stages of ovaries from 100 A.baremoze fish collected from Lake Albert were determined. Maturity condition was assessed by macroscopic inspection of gonads and histological methods. Macroscopic inspection was based on alterations in ovary size and appearance, whereas histological methods evaluated changes in oocyte stages. Gonado-somatic index (GSI) was used to assess the reproductive seasonality for a period of twelve months and was calculated as the proportion of ovary to body weight. Histological analysis confirmed the overall general appropriateness of macroscopic staging with stage IV being the most abundant in the samples and still the highest matching proportion between the two classifications. A correspondence graph obtained reveals few challenges in matching between macroscopic and microscopic classification for stages II and VI. Among ovaries macroscopically classified, 1% immature, 20% developing, 70% at spawning stage and 9% were at spent stage. The spawning pattern exhibited by A. baremoze indicate that this species undergo short spawning periods. This information is important in estimating maturity status which is a key in regulating A. baremoze fishery basing on spawning biomass.
Keywords: Alestes baremoze, Histology macroscopic, Ovary
Cite this paper: N. Kasozi, G. I. Degu, K. Atibuni, M. Kisekka, A. Owori-Wadunde, S. Mugerwa, Classification of Ovarian Stages of Alestes baremoze (Joannis, 1835): A Step towards Understanding Its Reproductive Biology, Frontiers in Science, Vol. 3 No. 4, 2013, pp. 107-113. doi: 10.5923/j.fs.20130304.01.
Figure 1. Map of Uganda with an insert of Lake Albert showing the location of Abok landing site |
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Figure 2. Three macroscopic maturity stages of ovary. (A) Developing ovary; (B) Spawning and (C) Spent ovary |
Figure 3. Developing ovary with oocytes in nucleus (NU) migration. Ovary with many primary growth oocytes PG – Primary growth oocytes; CA – cortical alveolar oocytes |
Figure 4. Spawning ovary with hydrated oocytes (HYD) and fused yolk globules (FS) |
Figure 5. Spent ovary with disorganization of ovary structures |
Figure 6. Percentage correspondence between macroscopic and microscopic classifications |
Figure 7. Variation in mean monthly female GSI over the study period (±standard deviation). Numbers along the x-axis show sample size for each month |