Assessment of PIT tag retention and post-tagging survival in metamorphosing juvenile sea lamprey

Abstract

Background: Passive integrated transponder (PIT) tags have been used to document and monitor the movement, behavior, or survival of numerous species of fishes. Data on short- and long-term survival and tag retention are needed before initiating studies using PIT tags on a new species or life stage. We evaluated the survival and tag retention of 153 metamorphosing juvenile sea lamprey Petromyzon marinus tagged with 12-mm PIT tags on three occasions using a simple surgical procedure. Results: Tag retention was 100 and 98.6% at 24 h and 28-105 days post-tagging. Of the lamprey that retained their tags, 87.3% had incisions sufficiently healed to prevent further loss. Survival was 100 and 92.7% at 24 h and 41-118 day post-tagging with no significant difference in survival between tagged and untagged control lamprey. Of the 11 lamprey that died, four had symptoms that indicated their death was directly related to tagging. Survival was positively correlated with sea lamprey length. Conclusions: Given the overall high level of survival and tag retention in this study, future studies can utilize 12-mm PIT tags to monitor metamorphosing juvenile sea lamprey movement and migration patterns.