Gonad morphology and histology of an endemic tooth-carp, Aphanius sophiae (Heckel, 1847) from Iran

This study presents the first details on morphological and histological characteristics of gonads and gonadal development stages of an endemic tooth-carp, Aphanius sophiae (Heckel, 1847) from a spring-stream system (south of Iran). The sampling was done from March 2012 to March 2013 using dip net, and a total of 226 individuals were collected. The gonads of specimens were removed, and then fixed in 10% formalin solution after checking their morphology and measuring their weights, lengths and widths. Based on the size, shape and weight of the gonads, degree of occupation of the body cavity, presence or absence of ripe oocytes or milt, diameter of the oocytes in the ovary, and histological observations, five stages of sexual maturation in females and males were determined by macroscopic and microscopic criteria. The results of the gonadal stages indicated that A. sophiae spawns at the beginning of spring.