Experimental examination of surgical procedures for implanting sonic transmitters in juvenile shortnose sturgeon and Atlantic sturgeon

Acoustic telemetry has become a leading tool for monitoring the movements of and habitat use by many sturgeon species worldwide; however, procedures for internal tagging of small juvenile sturgeon (<55 cm TL) are lacking. We examined effects of implantation technique on growth, tag retention, and survival of juvenile (<55 cm) Shortnose Sturgeon Acipenser brevirostrum and Atlantic Sturgeon A. oxyrinchus by using dummy acoustic tags. Two implantation techniques were used: (1) anchoring the tag to the wall of the peritoneal cavity and (2) no internal anchoring of the tag. These treatment groups were compared with two control groups: fish that received anesthetic only and fish that received anesthetic and an incision. Retention rate was significantly higher for anchored tags (88%) than for nonanchored tags (25%) in Shortnose Sturgeon juveniles, while Atlantic Sturgeon juveniles retained 100% of tags regardless of treatment. Nonanchored tags that were lost during the second week were expelled through the incision site, whereas later tag expulsions (during weeks 7 and 8) occurred through the anus. There was no significant difference in absolute growth and specific growth rates between the treatment groups throughout the 8-week study for either species. Growth of both species was significantly lower in the first week after surgery but increased and remained constant for the remainder of the experiment. Use of nonanchored tags significantly increased incision healing times for both species; however, Atlantic Sturgeon healed significantly faster (35 d) than Shortnose Sturgeon (42 d). No mortality occurred in any of the treatment groups. Results of this study suggest that juvenile Shortnose Sturgeon and Atlantic Sturgeon can undergo internal tag implantation resulting in long retention times with largely unaffected growth and no mortality