Studies on the Age, Growth and Reproduction Characteristics of the Chub, Leuciscus cephalus orientalis, (Nordmann, 1840) in Karasu River, Turkey

Authors: ORHAN ERDOĞAN, MUSTAFA TÜRKMEN, AYHAN YILDIRIM

Abstract: 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; L_t = 35.8765 (1-e^{-0.1241(t+1.16660)}), W_t = 583.2981 (1-e^{-0.1241(t+1.16660)})^{2.952}, W = 0.0150 FL^{2.952} in males and L_t = 41.4154 (1-e^{-0.1160(t+1.3207)}), W_t = 936.3338 (1-e^{-0.1160(t+1.3207)})^{2.980}, W = 0.0142 FL^{2.980} 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 (W_o), and fish age (t) were; F = 1.699 FL^{2.847} (r = 0.813), F = 969.424 W_o^{1.019} (r = 0.953), F = 95.669 W^{0.955} (r = 0.843) and F = 862.017 t^{1.589} (r = 0.814), respectively. In addition, the relationships between gonad weight and total weight, fork length of samples were; W_o = 0.394 + 0.723 W (r = 0.763) and W_o = -8.953 + 0.894 FL (r = 0.714) in females (in 119 samples), W_t = 1.598 + 0.037 W (r = 0.660) and W_t = -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).

Keywords: Chub, Leuciscus cephalus orientalis, Age, Growth, Reproduction, Karasu River.

Full Text: PDF