Mortality, Transmitter Retention, Growth, and Wound Healing in Juvenile Salmon Injected with Micro Acoustic Transmitters

AbstractA cylindrical micro acoustic transmitter (AT; weight in air = 0.2 g) has been developed for injection into the peritoneal cavity of fish. Laboratory studies can provide tagging guidelines to minimize the effects of implantation techniques and transmitter burden (transmitter weight expressed as a proportion of fish weight) before use of the AT in field studies. To establish guidelines for minimizing tagging effects, we examined response variables (mortality, transmitter expulsion, growth, and wound healing) for micro AT-injected juvenile Chinook Salmon Oncorhynchus tshawytscha over a wide range of sizes (65–104 mm FL). The overarching goal was to determine a minimum size threshold at which the adverse effects of micro AT injection on fish are minimized. Juveniles (n = 700) were separated into four treatments: (1) AT injection, (2) injection of an AT and a PIT tag (AT+PIT), (3) injection of visible implant elastomer (marked control), and (4) unmarked (true) control. Fish were evaluated once per week...