Standard weight equations of two sub-/tropic nonnative freshwater fish, Clarias gariepinus and Oreochromis niloticus , in the Sakarya River Basin (NW Turkey)

Abstract

Clarias gariepinus and Oreochromis niloticus are two hot-water fish species of African origin that have been recently reported to occur unnaturally in hot-water resources and springs in the Sakarya River Basin (northwestern Turkey). Within effective planning strategies to maintain native biodiversity, monitoring fishes' well-being can be useful to evaluate the status of nonnative fish populations and their degree of adaptation to new environments. Relative weight (W r) is a condition index widely used to estimate the well-being of fish by comparing the actual weight of a specimen with a standard weight (W s) that is the ideal weight of that fish at that length. In this study, length and weight data of C. gariepinus and O. niloticus, collected throughout the Sakarya River Basin, were used to estimate W s equations. The resulting W s equations were log 10 W s =-3.668 + 1.885 log 10 TL + 0.2087 (log 10 TL) 2 (TL range: 18-45 cm) for C. gariepinus and log 10 W s =-8.796 + 6.751 log 10 TL-0.8479 (log 10 TL) 2 (TL range: 8-28 cm) for O. niloticus. The use of these W s equations to estimate the fishes' condition is suggested as a monitoring tool to assess the status and the best management actions of these two nonnative species populations throughout the Sakarya River Basin.

Microbiota of catfish (Clarias gariepinus) tissues harvested from vials polluted with soil from e-wastes dumpsite

“…Clarias gariepinus is freshwater fish species of African origin, is one of the most cultured species in the world (Emiroğlu et al, 2018). This fish species is valuable for fish farming (aquaculture) due to its easy to farm especially in warm climates, fast growth rate, resistance to diseases, and high stocking density (Emiroğlu et al, 2018). Additionally, many catfish species are important human food source.…”

Pınarbaşı Deresi (Burdur, Türkiye)’nde Yabancı Balık Türü Hemichromis letourneuxi (Cichlidae)’nin İlk Kaydı

“…Salvelinus alpinus, S. fontinalis) have not established successfully in the natural ecosystems while some taxa including Carassius gibelio, Carassius auratus, Pseudorabora parva, Lepomis gibbosus, Atherina boyeri, Gambusia holbrooki, Oreochromis niloticus and Coptodon zillii have established successfully and generated self-sustaining populations in the natural ecosystems (Tarkan et al, 2015;Çiçek et al, 2015;Innal and Giannetto, 2017;Emiroğlu et.al., 2018). According to Emiroğlu et al (2018), several populations of O. niloticus reported from Çukurova, the Orontes River, Hirla Lake, Köyceğiz Lake and Sakarya River Basin. This species was also collected from research area (Pınarbaşı Creek, Burdur).…”