Inter-animal telemetry: results from first deployment of acoustic ‘business card’ tags

Prototype acoustic 'business card' (BC) tags were deployed on 4 free-swimming Gala- pagos sharks Carcharhinus galapagensis associated with a shark ecotourism operation near Haleiwa, Hawaii, USA. These transmitter/receiver tags employed mobile peer-to-peer (MP2P) technology that allowed the tagged sharks to exchange codes among each other and to detect other sharks implanted with standard one-way coded acoustic transmitters. Two tags were recovered (after 20 and 132 d); both tags had multiple detections of all other BC tags, and a comparison of detections made by these tags to those made by a fixed array of standard VR2 receivers indicated that the BC tags accurately captured the 'presence-absence' patterns of the other tagged sharks. Importantly, the BC tags detected sharks that were beyond the range of the fixed receiver array. The results indicate that the BC tag/MP2P approach can elucidate important inter-and intra-specific interactions among individ- uals in areas remote from traditional fixed receiver arrays.