The growth and reproduction of white bream (Blicca bjoerkna L. 1758) in an oligo-mesotrophic lake in northwest Anatolia (Sapanca, Turkey)

Growth parameters and the reproduction period of white bream (Blicca bjoerkna L. 1758) sampled from Sapanca Lake were determined monthly between November 2000 and October 2001. Three hundred and fifty white bream specimens caught ranged in age from 1(+) to 9(+) years, and the majority of the samples consisted of individuals of the 5(+)-year-old age group. The von Bertalanffy equation was determined as Lt = 22.169 (1 - exp {-0.215[t + 0.986]}), empty set: 2.02 for males and Lt = 31.917 (1 - exp {-0.122[t + 1.087]}), empty set': 2.10 for females. The length-weight relationship was estimated as W = 0.0046 TL exp. 3.315 +/- 0.002 for males (r(2) = 0.9653, P < 0.05), and W = 0.0036 TL exp. 3.417 +/- 0.002 for females (r(2)= 0.9671, P < 0.05). Regression coefficients for sex were significant (t-test, P < 0.05). The slope (b) significantly differed (ANCOVA, P < 0.05) between months. The fact that the b values for male and female white breams differed from 3.0 indicates that there was positive allometric growth. Sex ratio was 1:1.36 (chi(2); P < 0.05). Spawning period of white breams began at the end of April and continued until the beginning of July; water temperature during this period ranged between 13.7 and 28.5 degrees C.