Temporal distribution of accumulated metal mixtures in two feral fish species and the relation with condition metrics and community structure

The present study investigated temporal influences on metal distribution in gudgeon (Gobio gobio) and roach (Rutilus rutilus), and its relation to condition metrics and fish community structure. Fish communities were sampled in two seasons (autumn and spring) during two successive years and the Index of Biotic Integrity (IBI) was calculated. Cadmium, Cu, Pb, Zn and As concentrations were measured in gill, liver, kidney and muscle, and condition factor (CF) and hepatosomatic index (HSI) were measured. Cadmium (max. 39.0 μg g⁻¹ dw) and Zn (max 2502 μg g⁻¹ dw) were most strongly stored in kidney and liver and periodical influences on metal accumulation were observed. CF appeared to be a stable metric related to accumulated metal-mixtures and was best related to hepatic levels, while the HSI was less useful. Relations between single metal accumulation and IBI were influenced by sample period, however, when taking into account multiple metals periodical influences disappeared. - Highlights: • Cadmium and Zn are most strongly accumulated in kidney and liver. • Periodical influences on metal accumulation are observed. • CF is a stable metric related to metal accumulation, HSI seems less useful. • Relations between single metal accumulation and IBI are influenced by sample period. • Periodical influences are smaller when taking into account multiple metals. - Fish condition factor is a stable metric to assess the toxicity of accumulated metal mixtures in feral fish populations