Retention of radio tags in golden perch (Macquaria ambigua), silver perch (Bidyanus bidyanus) and carp (Cyprinus carpio)

Radio tagging and tracking are widely used to study freshwater fish; however, details of fish survival or tag retention rates are rarely reported. The results from five independent tagging trials associated with different tag attachment methods are reported in the present study. Implanted peritoneal cavity tags were trialled for two native Australia freshwater fish species (golden perch and silver perch) and introduced carp. Oesophageal and external tags were also trialled on silver perch. The results from the peritoneal cavity implantation trials in golden perch, silver perch and carp achieved an overall success rate of 81% (after 315 days), 18% (after 200 days) and 43% (after 323 days) respectively. The external attachment of radio tags to silver perch had limited success with all fish either rejecting their tags or dying before 256 days. Silver perch trialled with oesophageal tags had an overall success rate of 25% after 200 days. The trials indicate that internal tagging is suitable for longer-term radio tracking of golden perch, but further developments are required for longer-term applications to silver perch and carp. Tag rejection rates are unlikely to be constant between species or through time and this variability should be incorporated into the study design to prevent bias.