Ultrasonic telemetry, tracking and automated monitoring technology for sharks

Sharks were among the first marine animals to carry telemetry systems becau se of their size and the need to understand their interactions with humans. Modern telemetry systems can gather many kinds of data (limited only by im agination, funding and sensor types), indicating which animals are near tel emetry receivers and what they are doing. Receivers now range from simple a utonomous detector units for deployment in mid-water in large-scale grids, to sophisticated automated benthic recorders, to triangulating radio-linked buoy systems (RAP), to ship-borne transponders. In addition, archival tags can now gather and store data even while the shark is away, to be download ed later. Older types had to be recovered, but popup tags release from shar ks automatically, surface and transfer data to satellites, while CHAT tags download whenever queried by a nearby transponding acoustic receiver. Sophi sticated animal-borne tags dramatically increase the information gathered a bout sharks and their environment. The examples provided show the parallel progression of shark biology and acoustic biotelemetry illustrating that te lemetry systems are tools for gathering data, which can often be honed to f acilitate biological experiments. Future visions include sensors that direc tly measure shark swimming power and cardiac output, compressing the data s o that it can be delivered to RAP systems tracking multiple animals with me ter resolution in near real time. CHAT tags as small as 22 mm diameter shou ld be able to return similar data from trips of hundreds of kilometers. Con tinued communication between biologists and engineers is essential to devel op these technologies.