Addition of passive acoustic telemetry mitigates lost data from satellite-tracked manatees

Abstract

Satellite-tracked manatees routinely lose satellite tags or tag functionality, resulting in the loss of valuable data on migration and habitat use patterns. Fortunately, some movement data from these animals remain salvageable because manatees typically retain a peduncle belt containing an acoustic transmitter that can be detected with a submersible hydrophone. We deployed an array of moored datalogging hydrophones at key locations in our study area to detect manatee belt-embedded acoustic transmitters, a technique not typically used to track manatees. Our array was successful in detecting five tagged manatees, and concurrently detected compatible acoustic tags of other estuarine fauna (e.g. Bull Sharks) tagged by local researchers. Moored datalogging hydrophones, therefore, provided a method to mitigate the loss of satellite tags from estuarine megafauna, and enhanced collaborative opportunities with researchers who tagged other species using compatible equipment.