Breeding season, fecundity, length-weight relationship and condition factor of oreochromis niloticus L. (pisces: cichlidae) in Lake Tana, Ethiopia
1997
Zenebe Tadese (Bahir Dar Teacher's College, Bahir Dar (Ethiopia))
The breeding season, fecundity, length-weight relationship and condition factor of Oreochromis niloticus from Lake Tana, Ethiopia, were studied from monthly samples collected using a bottom trawl between March, 1992 and march, 1993. In Lake Tana Oreochromis niloticus spawns throughout the year, with a high activity between April and August peaking in June and July. The peak spawning coincided with the onset of the rainy season. There was a curvilinear relationship between fecundity and total length (TL) (logF = -0.01 + 2.01 LogTL, r = 0.86, p less than 0.001) and a linear relationship between fecundity and body weight (W) (F = 234.65 + 1.51TW, r = 0.84, p less than 0.001) and gonad weight (GW) (F = 394.55+29.1GW, r = 0.67, p less than 0.001). The length-weight relationship was less than a cube, LogTW = -1.373+2.742LogTL, n=680, r=0.97, p less than 0.001 indicating allometric growth of the fish. the length-weight regression coefficients for both males (2.748) and females (2.747) were almost the same. A significant seasonal fluctuation (ANOVA, p less than 0.001) was observed in the condition of the fish. The relatively low values during April to August may be due to the high energy cost of spawning.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
المعلومات البيبليوغرافية
تم تزويد هذا السجل من قبل Ethiopian Institute of Agricultural Research
