Survival and Swimming Performance of Small-Sized Gobiidae Implanted with Mini Passive Integrated Transponders (PIT-Tags)

Telemetry techniques are important tools in freshwater fish ecology but are limited by the size of the fish in relation to the size of the electronic tags. The emergence of very small PIT tags (8 mm, mini PIT tags) opens the door to study the individual movement and behavior of small-sized fish species and life stages previously outside the scope of fish telemetry. Although high survival from mini PIT tags have been shown in some groups of fish, suitability assessments are lacking for many taxa, and potential behavioral effects have rarely been evaluated. Here, we evaluate the survival tagging effects in small-sized (35–76 mm) Padanian goby (Padogobius bonelli) implanted with mini PIT tags. PIT-tagging was associated with high survival and tag retention in the tagged fish. No effects of PIT-tagging on volitional swimming activity nor on maximum swimming speed were found. Similar results were obtained implanting larger tags (12 mm) in gobies down to 50 mm in length. Our results indicate that PIT telemetry—using mini PIT tags—is applicable for the study of behavior and movement in small-sized gobies.