Mehdi Bibak

The length-weight relationship, breeding season and condition factor of Oxynoemacheilus bergianus from Jajrud River in the Namak Lake basin, Tehran Province, Central Iran, were investigated. Sampling was performed from March 2017 to February 2018. The biometric measurements and the body and gonad weights were monthly carried out for one year log sampling occasions, in a total of 546 specimens. The range of total length in males and females were 3.8-7.5 and 3-7.6 cm, and the range of total weight were correspondingly 0.36-3.53 and 0.2-4.67 g respectively. The calculated coefficient of determination (r2 ) in males and females was found to be 0.94 and 0.95, respectively reflecting a positive allometric (b > 3, p > 0.05) growth in both sexes. The gonadosomatic index and modified gonadosomatic index showed that O. bergianus spawns in the middle of spring in May. In agreement with that, the condition factor reached the minimum (0.60) in February, while the maximum (0.96) in May. Since there is poor conservation status of the species, this study aims to give a contribution for biologists and wildlife managers.