Investigation of some biological aspects of Cobitis taenia, index of clean water, Talar River (Mazandaran Province)

In this study some of the biological aspect like age and growth, length and weight and longitudinal growth of Cobitis taenia which have been fished in Talar River has been reviewed. Samples were taken from two locations, 20 km apart, from Oct. 2008 up to Sept. 2009. Samples were collected monthly by using an Electro-shocker machine .Collectively 410 speciemen of Cobitis taenia were obtained. Fishes have been examined for sex identification and 158 male , 119 Female and 133 immature have been determined from two locations during one year. This sampels belonged to 4 age groups of females and males. The proportion of male to female was 1/3 to 1. The relation between length and weight of males and females was W=0/671×TL+0/043 & W=1/593×TL+0/061. Growth parameters of Vonbertalanfi equation for males and females fish were as follows: L∞:680/09 K: 0/04 t0:0/106. Difference of Length Frequency distribution among males and females regarding the age were significant (P<0/05) the male fish had more frequency in the short length. The frequency for males, females and immatures was estimated to be32/4, 29 and 38/5percent. The weight and length of females was more than males. Average age for males was 0- 2 years and for females is 0- 3. Dominant age and average age for all fish were estimated to be 1 and 1/07 respectively.