Tagging juvenile pikeperch (Sander lucioperca (L.)) in the cheek with Passive Integrated Transponders (PIT) – impact on rearing indexes and tag retention
Zdzisław Zakęś, Marek Hopko
ABSTRACT. The aim of this study was to determine the impact of implanting passive integrated transponder (PIT) tags in the cheeks of two size classes of pikeperch (mean body weight (BW) – 63 g (S fish) and 105 g (L fish)) on basic rearing indexes and short-term tag retention. Four groups of fish were created: group S-M (smaller fish tagged in the cheek), group S-C (control group of untagged smaller fish ), group L-M (larger fish tagged in the cheek) and group L-C (control group of untagged larger fish). After tagging, the fish were held in recirculating systems and reared on formulated feed for 42 days. Significantly lower growth rates and worse feed conversion ratios (P < 0.05) in comparison to the control group were noted among the smaller tagged fish (group S-M) after 14 days of rearing. These differences became less distinct in the subsequent days of the study (P > 0.05). No period of decreased rearing index values was noted among the larger tagged fish (group L-M). Cheek implantation of PIT tags in pikeperch did not affect fish survival. The short-term retention of tags in both size classes of fish was equal and ranged from 97.4 to 100%. Considering the advantages of the PIT tag cheek implantation method, which includes no negative effect on fish growth, quick recovery following implantation, and high tag retention, as well as the safety of potential consumers, this method can be recommended for tagging pikeperch stocking material and releasing it into open waters.
Keywords: PIT, tag retention, pikeperch, Sander lucioperca, rearing indexes, tagging