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In the scope of this study, fish fauna of Küçük Menderes River and its tributaries, updated with the comparison of the recent ichthyofaunal studies, as well as the length-weight relations (LWR) and condition factors (CF) were estimated for 7 freshwater fish species belonging to six families from the river basin: endemic Oxynoemacheilus eliasi, Cobitis fahireae; invasive, Carassius gibelio, Atherina boyeri, transloce Perca fluviatilis and the native Squalius fellowesii, Cyprinus carpio. The fish samples were collected with various fishnets and DC electro-fishing devices from six stations in 2018 and 2019. The LWR of the fishes was studied based on 379 specimens. The estimated values of parameter b ranged from 2.884 (A. boyeri) to 3.176 (C. fahireae). The coefficient of determination (R2) was changed between 0.792 to 0.980 for all sampling localities. In the study, Fulton's condition factor ranged between 0.391 (S. fellowesii) to 3.080 (S. fellowesii); the relative condition factor ranged between 0.346 (O. eliasi) to 2.746 (S. fellowesii), respectively. This research is anticipated to contribute valuable insights for the conservation of the species, while also furnishing essential data to inform future fisheries management studies in the region. [ABSTRACT FROM AUTHOR]

The purpose of this study is to create awareness about the species of mosquito fishes (Gambusia holbrooki Girard, 1859) both vectors and ways of introduction to new aquatic habitats. Because the species creates risks, especially for the circumstance of the native and endemic fish fauna, studies about introduction stories of the species are quite important to prevent the risk. In the current report, mosquitofishes which are known as a highly invasive species were found in the crop content of a hen mallard duck (Anas platyrhynchos L., 1758) in an estuarine area, the Gediz River Basin (İzmir, Turkey). This report is the first record of a duck consuming mosquitofish. Although nevertheless, it is known that mallard duck feeding behaviour does not predominantly contain fish (they mainly feed on plant seeds), according to this observation, mosquitofish might be added to the prey list of mallards as a new type of food. Therewith, this feeding behavior also indicates that ducks might be a potential vector for the transport of invasive mosquitofishes. [ABSTRACT FROM AUTHOR]

Understanding the invasion success of alien species includes developing knowledge on how the biological traits of their populations respond to spatial differences in environmental conditions. For invasive fishes, while the influence of latitudinal and climatic gradients on their biological traits over large spatial scales is well established, there is less certainty in how these vary over smaller scales. Here, we tested the influence of a climatic and geographic gradient on the reproductive traits and body sizes of the invasive mosquitofish Gambusia holbrooki across five climatic regions in Turkey. The results revealed that the environmental conditions across eight sites provided two gradients: a latitudinal gradient (where northern sites were cooler with less rainfall) and a coastal–inland gradient (where changes were apparent from coastal areas and into inland areas). These gradients had marked effects on the traits of both sexes. In sites in coastal and southern areas, males had significantly larger gonopodia and females had greater fecundity than in inland and warmer areas, and with both sexes having body sizes that were smaller. The spatial differences in the male traits were suggested as being driven by differences in selection pressures at the sites that related to differences in their population abundances. The results revealed that environmental conditions across a relatively small spatial scale had some strong influences on the expression of specific biological traits of these mosquitofish populations, but with further work needed to test how these influences affect their invasion success. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)