Retention of passive integrated transponder tags in hatchery brook trout: Effect of tag size, implantation site, and double tagging

Abstract A fundamental assumption of mark‐recapture studies is that individuals do not lose their marks or tags, because tag loss can lead to biased parameter estimates. Retention 8‐mm full‐duplex and 12‐mm half‐duplex passive integrated transponder (PIT) tags implanted in the abdomen, opercular musculature, dorsal sinus age‐0+ hatchery male brook trout ( Salvelinus fontinalis ) was evaluated laboratory. Treatments included single‐ double‐tagged fish. Survival, growth, retention were monitored for 181–187 days 640 tagged fish 80 untagged controls. Survival 180 ranged 95%–100% affected by tagging. PIT‐tagging caused a short‐term reduction growth rates. Tag 100% implantation, 83.0% with operculum, 97.5% 99.6% abdomen. positively related size at independent whether double‐tagged. Double tagging one full‐ PIT different body locations would hedge against data relative single tagging, especially longer‐lived iteroparous species where through time more likely.