Population structure of Nile Tilapia Oreochromis niloticus (Linnaeus 1758) from Ken river, India

Abstract

The Ken river arises in the Damoh district of the Madhya Pradesh, and flows between latitude 23o 59’ to 25o 46’ 54” N and longitude 80o 15’ 45” to 82o 32’ 08” East covering area 28,058 sq km and length 430 km. The random fish samples were collected monthly between January 2015 to February 2016 for estimation of population structure of Oreochromis niloticus from the Ken river, India. The samples were measuring from 85 to 472 mm in total length which was varied from 0+ to 7+ age groups. According to the percentage occurrence 2+ age group was most dominated with male (31.14%) and female (31.45%) of the total stocks. Male population was dominated in 0+, 3+, 4+, 6+ and 7+ age groups with percentage share as 6.59%, 26.35%, 13.17%, 1.79% and 0.60%, respectively. But, female population was dominated in 1+, 2+ and 5+ age groups and contributed 18.24%, 31.45% and 5.65%, respectively in total catch. It breeds twice or thrice per year. The frequency of the breeding is most suitable for the stabilization of the stocks. The 7+ age group indicated that the ecological condition was favorable for O. niloticus from the Ken river, India. It is believed that this healthy stock (0+ to 7+ age groups) of O. niloticus from the Ken river is due to habitat degradation and water quality of the river.