Optimization of fish sampling procedure for evaluating the specific activity of ¹³⁷Cs, ⁹⁰Sr and accumulation coefficients

Problem of optimization of sampling procedure for evaluating the median of specific activity and accumulation coefficients of the ¹³⁷Cs and ⁹⁰Sr for the populations of different species of fish lived in the pond was observed. Estimates of the geometric standard deviation of the specific activity (1.2 - 1.9) and accumulation coefficients (1.8 - 2.3) of radionuclides for different species of fish were obtained. Minimum number of samples required for evaluating the median of the specific activity and corresponding accumulation coefficients of ¹³⁷Cs and ⁹⁰Sr with desired relative error was determined. In order to obtain the median value of the specific activity of ¹³⁷Cs with relative error δ = 20 % and confidence level of p = 0.95 at the time of harvest the following numbers of fish samples should be selected for the activity measurement: 16 - 20 samples of pike, perch, sunder, rudd and grass carp; 10 - 13 samples of catfish, bream, tench, carassius, pelecus cultratus; 8-9 samples of bream, roach, carp(common carp), bighead carp; and 5 samples of chub.