Comparison of two methods for implanting passive integrated transponders in Rio Grande silvery minnow

Authors: Thomas P. Archdeacon, W. Jason Remshardt, Tammy L. Knecht

Year: 2008 (xl)

Abstract

Uniquely-tagged animals provide an opportunity to study changes in population demographics and movement. Passive integrated transponder (PIT) tags are used to monitor growth, movement, and survival of fishes. Laboratory studies of tag retention and fish mortality following insertion of PIT tags in small-bodied, warmwater cyprinids, are rare. Mortality induced by two PIT tag implantation methods was compared, and tag retention after implantation was assessed. The relation between standard length and tag retention, and standard length and fish survival, in Rio Grande silvery minnow Hybognathus amarus was examined. Captive fish were randomly selected and PIT-tagged with 12.5 mm tags via surgical incision or needle injection and held in laboratory aquaria for 32 d. Mean survival (±SE) on day 32 was 99% (±0.01) for control fish, 87% (±0.06) for fish implanted by incision, and 50% (±0.05) for fish implanted by injection. We also tagged 280 fish by incision and held them in aquaria for 49 days. On day 49, survival and tag retention were both 90%. Longer fish had higher survival, but tag retention was not related to fish size. PIT tags are a reliable method to tag Rio Grande silvery minnow, if fish are greater than 60 mm standard length.