Climate change is affecting freshwater ecosystems globally, particularly those in semi-arid and arid regions. The Central Anatolian Ecoregion (CAE) in Türkiye has a semi-arid climate and is home to numerous endemic fish species. We used species distribution modelling to elucidate the distribution of sixteen endemic fish species in CAE and predicted their potential distributions for 2041–2060 and 2081–2100 based on the CMIP6 climate model. Half of the species are predicted to experience a significant loss of climatically suitable areas. Anatolichthys fontinalis, Gobio gymnostethus, Gobio hettitorum, and Pseudophoxinus burduricus will face a complete loss of suitable areas by 2081–2100 under a high emissions climate scenario, whereas Cobitis bilseli, Egirdira nigra, Gobio intermedius, and Squalius anatolicus will experience a significant loss. The other eight species can potentially benefit from climate warming if all other stressors remain equal. Anthropogenic stressors, such as water abstraction for irrigation, pollution, invasive species introductions, and dam construction, are already putting endemic fish populations in CAE under extreme pressure. Climate change is expected to exacerbate these threats. Regular monitoring of freshwater ecosystems and fish fauna in the CAE and protecting the region from key anthropogenic stressors are recommended to successfully conserve these endemic freshwater fishes under climate change.

Anthropogenic pressures on freshwater ecosystems are growing and pose serious threats to endemic fish species. This study aimed to identify the effects of anthropogenic pressures on an endangered species, Pseudophoxinus crassus (Ladiges, 1960), in the semi-arid Konya Closed Basin of Türkiye. The distribution area of the species was found to be reduced and the only population sampled exhibited a high incidence of external anomalies. It is hard to identify the origin of the anomalies; however, abrupt increases in salinity and reductions in dissolved oxygen values indicate that intensive agricultural activities might be responsible for the pressures on the population. Additionally, temporal changes in population growth parameters were identified and the effects of anomalies on fish condition factors were examined. Fulton`s condition factor was found to be reduced among specimens with external anomalies. This relationship between anomalies and fitness as reflected by the condition factor was also observed for two other endemic species. It is unclear whether these anomalies affect feeding behaviours, although specimens with lower condition factors are more likely to exhibit anomalies. However, it is clear that without the rehabilitation or restoration of natural habitats, fitness reduction will severely affect the statuses of populations, particularly in cases of isolated populations.

En tr A diverse genus of the Cyprinidae family, genus Chondrostoma Agassiz, 1832 has a wide distribution. More than half of the species distributes in Turkey, however there is little biological information about them. The aim of this study is to investigate the population parameters of Eastern Aegean Nase Chondrostoma holmwoodii and to evaluate the risks for the species in Tahtalı Reservoir. Fish sampling was carried out at 8 different sampling points at Tahtalı Reservoir in 2014 with multimesh gillnets. Population parameters such as age and sex composition, length frequence analysis and von Bertalanffy growth function were investigated. A total of 215 specimens of C. holmwoodii was sampled. Total length of the specimens varies between 4.3 - 28.2 cm and total weight 1.05 - 271 g. Age composition of the sampled specimens varies between 0 to V and most of the specimens were age-III. The von Bertalanffy growth parameters for C. holmwoodii was estimated as; = 395.30 mm (SD=63.80), K=0.17 (SD=0.05) and =46.45 mm (SD=9.41). In conclusion, main problem for C. holmwoodii population in Tahtalı Reservoir is predation risk by Perca fluviatilis Linnaeus, 1758. In order to offer conservation strategies for C. holmwoodii Tahtalı Reservoir population, diet, population structure, and life history traits of P. fluviatilis need to be studied in detail. Cyprinidae familyasına ait Chondrostoma Agassiz, 1832 cinsi geniş dağılım alanına sahiptir. Chondrostoma türlerinin çoğu Türkiye’de dağılım göstermesine rağmen biyolojileri hakkında yeterince bilgi bulunmamaktadır. Bu bağlamda Chondrostoma holmwoodii’nin Tahtalı Baraj Gölü’ndeki popülasyon parametrelerini incelemek ve mevcut popülasyonun risklerini değerlendirmek bu araştırmanın amacını oluşturmaktadır. Balık örnekleri 2014 yılında Tahtalı Baraj Gölü’nde belirlenen sekiz farklı örnekleme noktasından çokgözlü ağlar ile örneklenmiştir. Yaş ve cinsiyet kompozisyonu, boy frekans analizi ve von Bertalanffy büyüme fonksiyonu gibi popülasyon parametreleri araştırılmıştır. C. holmwoodii'nin total boyu 4,3 – 28,2 cm ve toplam ağırlığı 1,05 - 271 g arasında değişen 215 bireyi örneklenmiştir. Örneklenen bireylerin yaş kompozisyonu 0 ile V arasında değişirken popülasyondaki baskın yaş III olarak tespit edilmiştir. Ayrıca von Bertalanffy büyüme parametreleri; L_∞ = 395,30 mm (SS = 63,80), K = 0,17 (SS = 0,05) ve L₀ = 46,45 mm (SS = 9,41) olarak tespit edilmiştir. Sonuç olarak, Tahtalı Barajı Gölü’ndeki C. holmwoodii popülasyonu için temel tehditin Perca fluviatilis Linnaeus, 1758'in tür üzerindeki predasyon baskısı olduğu görülmüştür. C. holmwoodii’nin Tahtalı Baraj Gölü popülasyonu için koruma stratejileri belirlenirken P. fluviatilis'in diyet, popülasyon yapısı ve yaşam öyküleri de incelenmelidir.