Age, Growth, Population Structure and Reproductive Potential of a Vulnerable Freshwater Mullet, Rhinomugil corsula (Hamilton, 1822) from a Tropical River Betwa in Central India

Age, growth, population structure and reproductive biology of a vulnerable, freshwater mullet, Rhinomugil corsula (Hamilton, 1822) was studied from a perennial river of Central India between January 2008 and December 2009. Maximum seven annual rings were found and used to assess growth data in the samples representing 0 to +7 year classes. The annual increment in length was calculated to be 16.22 ± 6.06, 9.71 ± 4.32, 2.89 ± 3.85, 3.24 ± 2.73, 3.24 ± 1.17, 1.27 ± 1.24 and 0.58 cm in lst, 2nd, 3rd, 4th, 5th, 6th and 7th age groups respectively. The number of females was significantly higher than that of the males. Sex ratio (M:F) varied with season but the number of female specimens were greater throughout the year. Reproduction occurs likely between May and September. The mean size at first sexual maturity was 17.5 and 23 cm TL for male and female respectively. Gonadosomatic index (GSI) of both sexes showed maximum value in the mid of June which begins to decline till September. The present study developed a baseline data of a less studied fish which will help to evolve conservation and management strategy in view of changing environmental conditions in tropical rivers of India.