Survival, Growth, and Tag Retention in Estuarine Fishes Implanted with Passive Integrated Transponder (PIT) Tags

Abstract

We examined the effects of passive integrated transponder (PIT) tags on the survival, growth, and tag retention for two common estuarine fishes, mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides). A separate laboratory experiment was conducted for each species where individuals, ranging in initial size from 45 to 82 mm standard length (SL), were implanted with 8-mm or 12-mm PIT tags. Across both experiments, the probability of survival for tagged individuals ranged from 82 to 92%, probability of tag retention ranged from 82 to 91%, and probability of survival and tag retention ranged from 73 to 83%. For both species, most mortality and tag loss occurred for small (< 60 mm) individuals tagged with 12-mm tags, and generally early in the experiments. There was little effect of tagging on growth for individuals of either species compared to individuals in untagged control treatments. We recommend a minimum length of 55 mm SL for mummichog and 65 mm SL for pinfish when tagging with 8-mm or 12-mm PIT tags, as almost all fishes above these sizes survived and retained their tags. Direct comparison of our results with other studies was difficult because of variation in the tagging, husbandry, and experimental protocols used in experiments. A comparison among these different protocols would be useful to determine the least intrusive, most effective, and optimal procedure for a given species or group of estuarine fishes.