A Histological Study of Testis Structure and Reproductive Cycle in Male Bulatmai Barbel (Barbus capito),

This research was conducted to study the structure of testis and reproductive cycles of male Bulatmai barbel (Barbus capito). The samples were collected from captured fish during May till June 2001 in the Sefidrood and Polrood Rivers and then transferred to an earth pond. During one-year, from October 2001 till September 2002, the testis samples of adult specimens were collected. The testis samples were fixed using Boain and tissues were prepared for histological observation using parraffinization sectioning and haematoxylin-eosin staining. The testis of Bulatmai barbel was found lobular. Spermatogenesis starts with either releasing or the degeneration of sperm and continues up to the middle of autumn. Spermatogenesis then goes to a dormant period which lasts up to next spring. At the late of March along with water-temperature arising, spermatogenesis develops rapidly, with result of the appearance of sperm in lobules. This process continues up to July. So, the maximum of GSI indicate the maximum growth of testis which varies from 1.34±0.5 to 1.75±0.09 during the reproduction season.