Population status of Endemic fish Anatolichthys maeandricus (Cyprinodontiformes: Aphaniidae) in lakes and springs of West Anatolia under drought and intense anthropogenic influence

Abstract

In the Mediterranean Anatolia, the Lakes Region and Konya Closed Basin are the richest regions in terms of endemic fish with 55 species. An important place among them is occupied by the Oriental killifish genus Anatolichthys (Cyprinodontiformes: Aphaniidae). Many of them are still poorly understood. In these regions, global warming (droughts) and anthropogenic impact are serious threats to freshwater fishes. We have studied little explored populations of endemic A. maeandricus in Işıklı Lake and Işıklı Spring (Büyük Menderes River basin), influenced by both factors. Sampling was carried out seasonally (August, October 2021, February and April 2022), with a total of 233 and 157 specimens. Age ranges, male to female proportions, length and weight ranges were determined for two populations. The Von Bertalanffy growth equations were calculated for the populations in Işıklı Lake and Işıklı Spring, respectively, as Lt = 22.58 (1-e–0.0408(t+-0.303)) and Lt = 27.60 (1-e–0.0304(t+0.554)). The content of the digestive tract and stomach was examined. Gammarus sp. and Chironomid organisms were dominant in food of fish from both habitats. Although the growth parameters appear to be positive, drought and habitat destruction can be expected to endanger this endemic species in the near future. By our observations, over the past ten years, the habitat of the species has been severely restricted, and this situation has also affected other endemic fish species in the region. For these reasons, it is an urgent to protect the habitat of endemic fishes first and then the species themselves.