Table 3. Summary of monthly sex ratio (males:females) of Oreochromis niloticus in Lake Shala

Month	Male no.	Female no.	Sex ratio	χ2
January	13	9	1.45:1	0.89
February	11	14	0.79:1	0.32
March	19	12	1.58:1	2.04
April	12	20	0.60:1	1.6
May	16	13	1.23:1	0.35
June	14	27	0.52:1	3.13
July	14	21	0.67:1	1.17
August	9	21	0.43:1	3.43
September	3	13	0.23:1	3.85*
October	19	10	1.90:1	4.05*
November	16	11	1.45:1	1.14
December	19	7	2.7:1	10.29*
Total	165	178	0.93:1	0.47

p < 0.05.