Evaluation of Tag Retention, Healing, Growth, and Behavior in Age‐0 Muskellunge Following Acoustic Transmitter Implantation. (26th June 2019) - Walton‐Rabideau, Sarah E.
Abstract: The development of small acoustic transmitters has enabled researchers to monitor earlier life stages and smaller fish species than was previously possible. The underlying assumptions of any telemetry study are minimal tag loss and negligible effects on the behavior, survival, and growth of tagged individuals. To that end, tag retention, healing, survival, specific growth rates, and behavior were evaluated for 96 age‐0 Muskellunge Esox masquinongy (TL [mean ± SD] = 205 ± 10 mm) from three treatment groups. Tagged fish were compared to untagged controls and sham fish (fish that had undergone anesthesia and laparotomy but not transmitter implantation). Thirty‐two fish (tagged group) were implanted with one of the smallest commercially available acoustic transmitters (Juvenile Salmon Acoustic Telemetry tag; 12.0 × 5.3 × 3.7 mm, 0.217 g in air, >120‐d tag life) and monitored in a 4‐month, overwinter tank experiment. Tricaine methanesulfonate was used for anesthesia, incisions were closed with a synthetic absorbable monofilament, and all surgeries were conducted by a single trained researcher. All tags were retained throughout the experiment; surgical wounds healed within 30 d, 32% of sutures were retained at 120 d postsurgery, and survival did not differ between treatments. No biologically significant effects of tagging on mean relative growth rates (percent change in weight/d) were observed among the three groups (tagged, untagged, and sham fish) at 4 months postprocessing. The reaction of tagged fish to a moving object within 15 minutes after tagging was slower than the reaction at 7 d postsurgery, reiterating the importance of testing appropriate sedation methods prior to releasing fish in field studies. Results validate the utility of surgical implantation of small acoustic transmitters in juvenile Muskellunge for future studies, although immobilization methods for early life stages require further study.