Effects of turbine passage on tag retention and post-surgery healing in juvenile Chinook salmon implanted with an acoustic transmitter

Juvenile Salmonid Acoustic Telemetry System (JSATS) acoustic transmitters are now smaller (0.43g in air) than in previous years.  Thus the incisions required for implantation are also smaller.  This increases the likelihood that one suture could be used to adequately close the incision instead of two.  However, the effects of a dynamic river environment on performance of suture spacing are unknown.  The objectives of this study were to compare tag retention and post-surgery healing characteristics in juvenile Chinook salmon with 6mm long surgical incisions closed using one or two sutures, after simulated turbine passage (STP).  Juvenile salmon (95-135 mm) were surgically implanted with an acoustic transmitter and passive integrated transponder.  Incisions were closed with either one (treatment) or two (control) sutures.  All fish were exposed to STP in hyper/hypobaric chambers.  The lowest pressures fish experienced during STP varied from 6.4-14.6 psia.  No tag or suture loss occurred in either treatment.  Mortality, mortal injury, and incision tearing were similar between treatments.  Further research is needed to evaluate longer term tag retention and healing in fish with one suture and to determine the influence of passing multiple dams.