Fig. 1

Photograph of a CTD-SRDL, with visible hardware components labelled (photograph by Lars Boehme, SMRU). The tag is housed in normal solid epoxy rated either to 500Â m or 2000Â m depth. Standard sensors include pressure, a wet/dry saltwater switch, temperature, conductivity. The tag has a PC interface, is powered by a primary cell (battery) and the standard version includes an antenna