Comparison of reproductive indices under the influence of species and season in Periophthalmus waltoni and Boleophthalmus dussumieri (Teleostei: Mudskipper) living in Khor Ghanam, Khuzestan province, Iran

The internal origin of reproduction is controlled by biological clocks. In different conditions, there may be a daily, monthly or annual cycle and it depends on the geographical characteristics of the place where the fish lives. Thus, in the present study, the reproductive indices under the influence of species and season in Periophthalmus waltoni and Boleophthalmus dussumieri, which live in Ghanam estuary, Khuzestan province, were investigated. Sampling was performed in two seasons of spring and autumn 1401-1400. A total of 53 fish of both species were caught live by hand and transferred to the laboratory in spring and autumn. After explaining the samples and extracting the sexual gonads, the reproductive characteristics were examined. In this study, the prevalence of P. waltoni in both autumn and spring was higher than the other species. In addition, in both seasons, for both samples, the male gender was dominant and accounted for the highest frequency. For B. dussumieri, although the male population was more abundant in spring, their gonadal index was higher in autumn and the males of this species were more active in reproduction in spring than in spring. However, for both species in the female, sexual maturation peaks in the spring. It can be concluded that due to climate change and the major role of ecological conditions, while increasing temperature and humidity in hot to cold seasons, biological and food activities have increased and the amount of weight has a direct relationship with reproductive capacity.