Survival of and Tag Retention in Southern Redbelly Dace Injected with Two Sizes of PIT Tags

Passive integrated transponder tags are a common method used in fish ecology research, and their feasibility for use has been well studied in salmonids. Several studies suggest that effects of PIT tagging may be species dependent and these effects should be addressed prior to conducting large-scale tagging studies. In a series of laboratory experiments, we tested factors influencing survival and tag retention in Southern Redbelly Dace Chrosomus erythrogaster. In the first experiment, we tested the effects of tagger and fish length on survival and retention over 30 d for dace tagged with 9-mm PIT tags. Survival was high (84%) while retention of tags was low (30%). We detected no significant effect of tagger experience on survival or tag retention. Logistic regression determined that tag retention increased with fish length. A second experiment showed similar trends for survival (80%) and retention of 9-mm tags (25%) as observed in experiment 1, but retention (86%) was significantly higher for dace tagged with 8-mm tags over the same period. All dace in our sham-injection treatment (needle puncture of the peritoneal cavity) survived, eliminating needle puncture as a source of mortality. Our study, combined with a literature review of PIT-tagging studies, suggests that dace and other cyprinids greater than 60 mm can be tagged reliably with 9-mm tags and individuals greater than 50 mm can be tagged with 8-mm tags.