Electronic Tag Retention and Survival of Giant Salamanders after Surgical Implantation

Abstract

Expansion of the habitat occupied by the hybrid giant salamander (Japanese×Chinese giant salamander, Andrias spp.) in the Kamo River of Kyoto Prefecture, Japan, has been a serious problem for the conservation of the Japanese giant salamander, A. japonicus. Thus, the movement and behavior of hybrid giant salamanders must be determined to quantify their ecological impact. Biotelemetry facilitates the long-term tracking of this species in rivers if transmitters are surgically implanted successfully. However, to use this approach successfully, it is important to understand the effects of surgical implantation and the healing process after surgery on animals. Nine hybrid salamanders were surgically implanted with dummy transmitters, while three individuals were incised without implanting any transmitters as the control treatment. Three months of observation after surgery showed that all individuals survived and retained transmitters. No hernia was observed in implanted individuals, and surgical incisions completely healed in one to two months. Body weight increased in all individuals, with no significant difference being observed in the weight gain and growth rate of implanted versus control individuals. The present study demonstrated the successful retention of implanted dummy transmitters in giant salamanders for three months without severe effects, suggesting the utility of biotelemetry for monitoring individuals in the wild.