New Tagging Technology for Small, Listed Non-Salmonid Fishes: PIT and Acoustic Tag Retention and Survival of Delta Smelt

Recent advances in the development of increasingly smaller passive integrated transponder (PIT) tags and Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters now allow these technologies to be considered for smaller fishes not commonly investigated using such methods. In the upper San Francisco Estuary, information on the movement and behavior of Delta Smelt, a small (typically less than 80-mm FL) listed species, is principally inferred from monitoring. The ability to track individuals would substantially improve knowledge of the species’ habitat use, migration routes, and entrainment vulnerability. Building on the body of juvenile salmonid telemetry studies, the present laboratory study investigated 28-day survival and tag retention of cultured Delta Smelt (>70 mm) with 0.03-g PIT tags and prototypical 0.22-g dummy JSATS transmitters. PIT tags were injected with a 16-gauge needle. Dummy JSATS transmitters were injected with an 8-gauge needle or manually implanted through a small incision without suturing. Initial results suggest high survival with PIT tags but relatively low survival with dummy JSATS transmitters. Future studies will investigate how these tags affect Delta Smelt swimming performance. Establishment of successful tagging methods will enhance the understanding of Delta Smelt transit times and behavior at large water diversions in the estuary’s tidal freshwater zone.