Effects of transmitter application procedures on growth, survival, and tag retention of juvenile least cisco Coregonus sardinella

Technological advances have led to smaller transmitters for telemetry studies involving small fishes, including juveniles, which minimize effects on fish performance and retention caused by tag burden. We evaluated three transmitter application procedures (external attachment and internal implantation with and without a trailing antenna) on the growth, survival, and tag retention of juvenile least cisco Coregonus sardinella over a 60-day laboratory experiment. For fish that received internal transmitters, we also examined the effects of suture type (absorbable versus non-absorbable) and suture knot adhesive (use versus non-use of 3M™ Vetbond™). In general, there were minimal to no effects of suture type or the use/non-use of knot adhesive on fish performance. Only least cisco in the control (no transmitter) and external transmitter groups exhibited positive growth over the experimental period. Despite growth differences among treatments, there were no significant differences in final mean total length and wet weight among treatment groups. Least cisco with internal transmitters exhibited significantly lower survival (trailing antenna: range, 53-73%; no trailing antenna: 80%) than fish in control (100%) and external transmitter (93%) groups. External transmitters were not shed by juvenile least cisco; however, transmitter shed rate ranged from 0% to 33% for fish in internal implant treatments. Our results showed that externally attached transmitters had a lower impact on fish growth, mortality, and tag retention than internal implants, which is an important consideration for telemetry evaluations involving fish that are susceptible to handling stress such as juvenile least cisco.