Tagging juvenile European perch (Perca fluviatilis L.) with passive integrated transponders (PIT) – impact on growth, condition, and physiological indexes

The aim of the study was to determine the impact of intramuscular tagging with passive integrated transponders (PIT tags) on the basic condition and hematological and biochemical indexes of the blood plasma of juvenile European perch (initial body weight of approximately 80 g). Throughout the observation period, i.e., for 42 days following PIT implantation, the procedure was not noted to have had a negative impact on fish growth, condition, or feed conversion ratio. The blood plasma biochemical indicators analyzed did not differ statistically significantly between the fish tagged with PIT and the untagged control group. No significant impact from this procedure was noted in the hematological indexes tested. Only with regard to the mean corpuscular hemoglobin (MCH) parameter was the value significantly lower in the fish tagged with PIT than in the control group (P ≤ 0.05). The difference determined was 1.40 pg (28.78 vs. 30.18). The MCH level in the fish tagged with PIT most probably was within the norm for this species. High tag retention (100%) and the lack of any significant impact on condition or hematological and biochemical indexes (with the exception of MCH) permits recommending this tagging method for use in juvenile perch.