Assessment of population dynamics of T. putitora (Ham, 1822) in the Nayar river basin

The present study analyzed the population characteristics of Tor putitora in their breeding and nursery grounds located in Western Himalayan region. From a sample size of 400 individuals, growth parameters such as asymptotic length, growth rate and growth performance index were estimated as 80.01 cm, 0.810 per year and 3.71 per year while the potential longevity was estimated as 4.6 years. The mortality parameters such as total, natural and fishing mortality were estimated as 2.88 /year, 1.05/ year and 1.83 / year respectively. The length at 25 %, 50% and 75% susceptibility to capture was estimated as 40.87 cm, 38.11 cm and 35.34 cm respectively. The fishing mortality and exploitation beyond optimum level and maximum sustainable exploitation ratio (Emax) indicate the overly exploitation of Mahseer resources in their breeding and nursery grounds. This indicates that the examined breeding and nursery grounds in Western Himalaya are facing intense "growth and recruitment overfishing" which may result in stock collapse in the forthcoming years.