Morphomeristic comparison between male and female of brown trout (Salmo trutta) in Hevigh (Guilan Province) and Lar rivers (Mazandaran Province)

Salmo trutta belong to salmonid fish family exist in upstream and midstream region of most rivers entering southern Caspian Sea and some inland waters of Iran. 41 spicemens from Hevigh (Guilan province) and 90 spicemens from Lar rivers (Mazandaran province) in 2009 and 2010 were caught, and were studied morphometric and meristic characteristics of them in male and female. Studied fish had a fork length 94 to 176 (121.6-22.8) mm in Hevigh river and 122 to 448 (212.81-49.6) mm in Lar dam rivers. The results showed 104 to 139 scales on lateral line, 9 to 11 and 7 to 11 branched rays in dorsal and anal fins, respectively, 8 to 12 branchiostegal rays and 14 to 19 gill rakers on first arch. The results on 58 morphometric measurements showed 31 of them such as head length and head height, the length of the upper jaw, eye diameter, maximum and minimum body depth differed between male and female in Hevigh river.There was no difference between both sexes in the rivers of Lar dam in meristic but in 18 factors, there was significant difference.