Size-dependent Concentrations of Radiocesium and Elements in Muscles of Flathead Flounder Hippoglossoides dubius

Abstract

Concentrations of stable ¹³³Cs in muscles of flathead flounder Hippoglossoides dubius were determined in separate individuals by means of neutron activation analysis, and were found to decrease with increasing size (age), following the relationship C=470L^-1.05 (C, stable Cs concentration in μg/kg wet weight and L, standard length of fish in cm), over the range of 16.0 to 36.0cm standard length. von Bertalnffy growth model for the sample fish was fitted as: L_t=37.55(1-e^{-0.1030(t+1.83)}), (L_t, standard length in cm at age t). Since the specific activity or ₁₃₇Cs: stable Cs ratio was found to be fairly constant(average 1.2×10⁴ Bq/g Cs) over this range, radiocesium ¹³⁷Cs concentrations are expected to vary withfish size according to the relationship given above. In radio-environmental monitoring programs, the size composition of samples may have to be taken into consideration in assessing monitoring data.