A subdermal tagging technique for juvenile sturgeon using a new self-powered acoustic tag

Abstract

AbstractBackgroundA new technology for a self-powered acoustic tag (SPT) was developed for active tracking of juvenile fish, intended to avoid the typical battery life constraints associated with active telemetry technology. We performed a laboratory study to evaluate a subdermal tagging technique for the SPT and effects of the tag on survival, tag retention, and growth in juvenile white sturgeon (Acipenser transmontanus).ResultsSurvival was associated with tag retention. White sturgeon implanted with the SPT (n = 30) had 93% survival and tag retention by day 28, 67% by day 101, and 38% by day 595 post-tagging. Sturgeon implanted with a passive integrated transponder (PIT) tag only (control group) had 96% survival and tag retention by day 28, and through day 101 post-tagging. Fish in the PIT group were repurposed after day 101, so no comparisons with this group were made at day 595 post-tagging. Specific growth rate (SGR) for fork length was a median of 0.25% day−1by day 28 for the SPT group, which was significantly lower than the PIT group (median: 0.42% day−1;n = 27). The SPT and PIT groups had similar SGR fork length by day 101 post-tagging (0.22 and 0.25% day−1, respectively). SGR weight was also lower for the SPT group compared to the PIT group on day 28 (1.39 and 2.11% day−1, respectively), but the difference again dissipated by day 101 (0.79 and 0.88% day−1, respectively).ConclusionThe tagging technique and placement of the SPT allowed the tag to remain upright along the flank of the sturgeon to ensure maximum battery output of the SPT; however, retention rates of the SPT were not ideal. We provided suggestions to improve the tagging technique. Suggestions included tagging fish that are > 400 mm FL, moving the incision location to extend the cavity and create a pocket for the placement of the SPT, and performing a quantitative wound-healing evaluation. Future studies are therefore recommended to evaluate these suggestions.