Kas›m 1995 ile Ekim 1997 tarihleri aras›nda Karasu Nehri (40° 45´ 33´´ E, 39° 56´ 16´´ N)’ nda yürütülen bu çal›flmada toplam 759 adet tatl› su kefali incelenmifltir. Populasyonda erkeklerin I-VII, diflilerin ise I-IX yafllar aras›nda da¤›l›m gösterdi¤i ve ikinci yafl grubunun dominant oldu¤u belirlenmifltir. Örneklerin % 50,46’ s› erkek % 49,54’ ü ise difli bireylerden oluflmakta olup, erkek ve difli oran› 1:1,019 olarak hesaplanm›flt›r. Von Bertalanffy büyüme parametreleri ve boy a¤›rl›k iliflkisi s›ras›yla erkeklerde Lt = 35,8765 (1-e-0,1241(t+1,16660)), Wt = 583,2981 (1-e-0,1241(t+1,16660)) 2,952 ve W = 0,0150 FL2,952, diflilerde ise Lt = 41,4154 (1-e-0,1160(t+1,3207)), Wt = 936,3338 (1-e-0,1160(t+1,3207)) 2,980 ve W = 0,0142 FL2,980 olarak hesaplanm›flt›r. Kondisyon faktörü erkek, difli ve erkek+difli kar›fl›m›nda s›ras›yla 1,32, 1,35 ve 1,33 olarak bulunmufltur. Fekundite (F) ile boy (FL), a¤›rl›k (W), gonad a¤›rl›¤› (Wo) ve yafl (t) aras›ndaki iliflkiler s›ras›yla F = 1,699 FL2,847 (r = 0,813), F = 969,424 Wo1,019 (r = 0,953), F = 95,669 W0,955 (r= 0,843) ve F = 862,017 t1,589 (r = 0,814) olarak hesaplanm›flt›r. Ayr›ca, gonad a¤›rl›¤› ile çatal boy ve toplam a¤›rl›k aras›ndaki iliflkiler s›ras›yla diflilerde (119 örnek) Wo = 0,394 + 0,723 W (r = 0,763) ve Wo = -8,953 + 0,894 FL (r = 0,714), erkeklerde ise (117 örnek), Wt = 1,598 + 0,037 W (r = 0,660) ve Wt = -2,965 + 0,429 FL (r = 0,643) olarak belirlenmifltir. Ortalama fekundite III. yaflta 5012 adet/difli, VIII. yaflta ise 25000 adet/difli olarak bulunmufltur. Ortalama 119 µm olan yumurta çap› 100 ile 137 µm aras›nda de¤iflmektedir. ‹lk cinsi olgunluk yafl› erkeklerde II difliler ise III. yafl olarak belirlenmifl olup, yumurtlama May›s ve Temmuz aylar› aras›nda gerçekleflmektedir.

This study is based on the examination of 759 chubs from Karasu River (40° 45´ 33´´ E, 39° 56´ 16´´ N) between November 1995 and October 1997. This population comprised seven age groups of males and nine of females. The second age group was dominant in the population. Individuals were composed of 50.46% males and 49.54% females. The male and female ratio was 1:1.019 (M:F). The Von Bertalanffy growth parameters and length-weight relationships were; Lt = 35.8765 (1-e-0.1241(t+1.16660)), Wt = 583.2981 (1-e-0.1241(t+1.16660))2.952, W = 0.0150 FL2.952 in males and Lt = 41.4154 (1-e-0.1160(t+1.3207)), Wt = 936.3338 (1-e-0.1160(t+1.3207))2.980, W = 0.0142 FL2.980 in females, respectively. The condition coefficients of male, female and all specimens were; 1.32, 1.35 and 1.33, respectively. The relationships between fecundity (F) and fish length (FL), fish weight (W), gonad weight (Wo), and fish age (t) were; F = 1.699 FL2.847 (r = 0.813), F = 969.424 Wo1.019 (r = 0.953), F = 95.669 W0.955 (r = 0.843) and F = 862.017 t1.589 (r = 0.814), respectively. In addition, the relationships between gonad weight and total weight, fork length of samples were; Wo = 0.394 + 0.723 W (r = 0.763) and Wo = -8.953 + 0.894 FL (r = 0.714) in females (in 119 samples), Wt = 1.598 + 0.037 W (r = 0.660) and Wt = -2.965 + 0.429 FL (r = 0.643) in males (in 117 samples), respectively. Fecundity varied from a mean of 5012 eggs per female (III years old) to a mean of 25,000 eggs per female (VIII years old). Egg diameter varied between 100 µm and 137 µm with a mean of 119 µm. The reproduction period of this species inhabiting Karasu River was between May and July, and the first reproduction ages were; age II (for males) and age III (for females).