Technical Report

Investigation Use of Passive Integrated Transponder (PIT) Tags for Rio Grande Silvery Minnow

URL: https://webapps.usgs.gov/mrgescp/documents/Remshardt%20et%20al_2008_Investigation%20Use%20of%20Passive%20Integrated%20Transponder%20%28PIT%29%20Tags%20for%20RGSM.pdf

Date: 2008/12/08

Author(s): Remshardt W.J., Archdeacon T.P., Knecht T.L.

Publication: Report prepared for the U.S. Bureau of Reclamation, 20 p.

Abstract:

We compared passive integrated transponder tag-induced mortality by two implant methods (surgical and injection), and assessed long-term tag retention after surgical implant in Rio Grande silvery minnow Hybognathus amarus. Mean survival (±SEM) on day 32 was 99 (±0.013), 87 (±0.060), and 50% (±0.046) for control, surgically implanted, and injected fish, respectively, in Experiment 1. For Experiment 2, we tagged 280 fish by surgical implant and held them in aquaria for 49 days. Survival and tag retention on day 49 was 90 and 91%, respectively. Survival was significantly higher in fish with greater standard length (P < 0.0001), but there was no relationship of tag retention to fish size. We conclude PIT tags are a feasible method to tag Rio Grande silvery minnow, if fish are greater than 60 mm standard length. Fish should be held in captivity for a minimum of 6 days after tagging for best survival. We met the minimum criteria set in the original proposal for survival and retention, and have completed Phase I (comparison and selection of tagging methods). Phase II will begin in 2008 and includes field-testing the weir antenna and large-scale tagging and release of up to 10,000 Rio Grande silvery minnow.