Biological parameters of Bonylip barb (Osteochilus vittatus Valenciennes, 1842) in Lake Rawa Pening Semarang Regency

Abstract

Bonylip barb (Osteochilus vittatus Valenciennes, 1842) is an indigenous fish which is the main target of fishermen in lake Rawa Pening. This study aims to determine the biological parameters including length-weight relationship, con-dition factor, and sex ratio of bonylip barb in lake Rawa Pening, Semarang Regency. Fish sampling was conducted biweekly from October 2019 to March 2020, caught using bamboo blinds operated by local fishermen. Data collected consisted of total length, individual weight, and sex. Data on the length-weight relationship and condition factors were analyzed descriptively, while the sex ratio was analyzed with the chi-square test (χ2). The results showed that female bonylip barb was obtained as many as 392 individuals with a length-range between 10.0-26.0 cm and a weight range between 14.5-264.1 g. The male counted 255 individuals with a length range of 10.2-22.4 cm and a weight range of 15.0-160.9 g. The growth pattern was allometric negative. The equation of the length-weight relationship of female was W = 0.0186 L 2.9096 (R² = 0.9527), and the male was W = 0.0151 L 2.9689 (R² = 0.9386). The value of the average condition factor of females was 1.05, and the males was 1.02. The condition factor in females was in excellent condition (> 1.05), and males were in good condition (0.95-1.05). The overall sex ratio of male and female was 1:1.54. It means that females population was significantly higher than males.