Population parameters of stargazer (Uranoscopus scaber Linnaeus, 1758) in the southeastern Black Sea region during the 2011-2012 fishing season

Abstract

The population parameters of stargazer (Uranoscopus scaber Linnaeus, 1758) were studied regarding age composition, sex ratio, growth, survival and mortality rates, and the exploitation rate in the southeastern Black Sea near the coast of Turkey during the 2011-2012 fishing season. According to ageing analysis of the samples, age group 1 is the most abundant (47.76%), followed by age 2 (41.04%), age 3 (9.33%), age 0 (1.12%) and age 4 (0.75%). Mean totals as well as total lengths and weights for males and females were 14.5 +/- 0.22cm and 12.9 +/- 0.19g, 16.6 +/- 0.24cm and 62.1 +/- 2.76g, and 37.2 +/- 1.92cm and 87.1 +/- 3.88g, respectively. The mean condition factor was K=0.0167, while the sex ratio was 53.98% female, 38.75% male and 7.27% immature. Length-weight, age-length and age-weight equations were W=0.014xL(3.059), L-(t)=44.5*[1-e(-0.148*(t +1.242))] and W-(t)=1544.4*[1-e(-0.148*(t + 1.242))](3.059), respectively. The computed survival rate (S), instantaneous total mortality rate (Z), annual mortality rate (A), natural mortality rate (M) and fishing mortality rate (F) were S=28.94%, Z=1.24year(-1), A=71.06%, M=0.26year(-1) and F=0.98year(-1), respectively. The exploitation rate was 0.79, which is above the optimum exploitation levels.