Tag Loss and Short-Term Mortality Associated with Passive Integrated Transponder Tagging of Juvenile Lost River Suckers

Abstract

Passive integrated transponder (PIT) tags are commonly used to mark small catostomids, but tag loss and the effect of tagging on mortality have not been assessed for juveniles of the endangered Lost River sucker Deltistes luxatus. I evaluated tag loss and short-term (34-d) mortality associated with the PIT tagging of juvenile Lost River suckers in the laboratory by using a completely randomized design and three treatment groups (PIT tagged, positive control, and control). An empty needle was inserted into each positive control fish, whereas control fish were handled but not tagged. Only one fish expelled its PIT tag. Mortality rate averaged 9.8 ± 3.4% (mean ± SD) for tagged fish; mortality was 0% for control and positive control fish. All tagging mortalities occurred in fish with standard lengths of 71 mm or less, and most of the mortalities occurred within 48 h of tagging. My results indicate that 12.45- × 2.02-mm PIT tags provide a viable method of marking juvenile Lost River suckers that are 72 mm or larger.

Received February 18, 2011; accepted July 27, 2011

ACKNOWLEDGMENTS

Ron Stone and Scott Foott of the California–Nevada Fish Health Center spawned, reared, and cared for the fish used in this experiment. Alex Wilkens and Darin Taylor of the U.S. Bureau of Reclamation tagged the fish and assisted with data collection. Scott VanderKooi of the U.S. Geological Survey assisted with study design and reviewed an early draft of this manuscript. David Hewitt, Eric Janney, and Jack Toumikoski also reviewed an early draft of this manuscript. Reference to trade names does not imply endorsement by the U.S. Government.