Nurgül Şen Özdemir 1* , Muammer Kırıcı 1 , Ünal İspir 2 , Mustafa Koyun 3 , Fatma Caf 1 - 114 - DOI: 10.51756/marlife.1140540 Mean length-weight relationship and condition factor of some Cyprinid fishes in Göynük Stream, Murat River of Eastern Türkiye, Bingöl Marine and Life Sciences The Length-weight relationships (LWRs) are very important to data for accurate estimate of populations in stock menagement. In this study, the length-weight relationships and Fulton’s condition factor (K) of some fish in Göynük Stream, Murat River (Bingöl/Turkiye) were examined. The LWRs and condition factor (K) of Cyprinon macrostomus, Garra rufa, Barbus lacerta, and Acanthobrama marmid were analyzed between March 2017-February 2019. LWRs was estimated using the linear regression model. LWRs were obtained as total weight (TW) = 0.013L 2.98 , 0.057L 2.40 , 0.016L 2.79 and 0.029L 2.82 for C. macrostomus, G. rufa, B. lacerta and A.marmid, respectively. The b values acquired in the four fish species ranged from 2.13-2.57 (G. rufa-Male; Female) to 2.77-3.34 (B. lacerta-Female; Male). Only B. lacerta males had a positive allometric growth versus the males and females of all species had a negative allometric growth. The K of the fish species varied from 0.90-0.99 (A. marmid-Male; Female) to 1.27 (G. rufa-All), indicating that most of the fish were in good condition. However, C. macrostomus and G. rufa were better condition than B. lacerta and A. marmid. The study has provided baseline information on the LWR and K of the fish species in Göynük Stream. The data that would be useful to adapt the adequate regulations for sustainable fish stock estimation in the stream for fishery biologist. 1 Department of Veterinary Medicine, Vocational School of Food, Agriculture and Livestock, Bingöl University, 12000, Türkiye 2 Malatya Turgut Özal University, Doğanşehir Vahap Küçük Vocational School, Department of Fisheries, Malatya, 44530, Türkiye 3 Department of Molecular Biology and Genetics, Faculty of Science and Art, Bilecik Şeyh Edebali University, Bilecik, 11000, Türkiye Keywords Condition factor Length-weight relationships Murat River C. macrostomus G. rufa B. lacerta A. marmid Journal Homepage: https://dergipark.org.tr/en/pub/marlife Cite this article as Şen Özdemir, N., Kırıcı, M., İspir, Ü, Koyun, M. & Caf, F. (2022). Mean length-weight relationship and condition factor of some Cyprinid fishes in Göynük Stre- am, Murat River of Eastern Turkiye, Bingöl. Marine and Life Sciences, 4(2): 114-122. Research Article Accepted: 30.08.2022 Received: 05.07.2022 ABSTRACT *Corresponding author: nsozdemir@bingol.edu.tr Affiliations E-ISSN: 2687-5802 Introduction Length and weight data of fish are very important parameters for population dynamics (Krause et al., 1998), growth and death rates of the fish (Kohler et al., 1995). Also, the length-weight relationship (LWR) can also helps for stock management of the fish population (Sparre and Venema 1998, Blackwell et al., 2000). The LWR is important for calculating the present biomass of the fish population in a reservoir (Petrakis and Stergiou, 1995). Studies of the LWR of fishes were performed for years. The LWRs has been studied by many researchers in different fish species viz., Clarias gariepinus (Ayo-Olalusi, 2014); Oreochromis niloticus (Silva et al., 2015); Astyanax aff. fasciatus (Furuya et al., 2014); Pseudorasbora parva, Atherina boyeri, Aphanius danfordii, Tinca tinca, and Cyprinus carpio (Kırankaya et al., 2014); Capoeta umbla (Serdar and Özcan, 2016); Acanthobrama marmid, Capoeta trutta, Arbus luteus and Chalcalburnus mossulensis (Başusta and Çiçek, 2006); Carasobarbus luteus, Chondrostoma regium, Clarias gariepinus, Anguilla anguilla and Cyprinus carpio (Özcan, 2008). In addition, the a and b values, which are the LWR parameters, allow the morphology of populations distributed in different habitats and the life processes of fish species to be compared (Yedier et al., 2019; Yılmaz et al., 2010). Condition factor (K) is a parameter related to the body shape of the fish and serves as an important factor in understanding detailed properties of the habitat. This factor shows the nutrient