An identification tag for sea mammals

The objective of this work is to provide a more permanent identification of individual animals that will outlast the annual moult and work up to a range of 1000 m. Of the techniques that are available radio methods are the most well developed. Compact and low power devices are now commercially available in the 444.72 to 434.2 MHz band. Directive antennas provide some spatial separation, several animal tags responding within the same antenna field of view would require some anti-collision protocol