A strange-looking yellow "fish" has been lurking in the waters off the southern coast of Vancouver Island recently. Called a Slocum underwater glider, the 1.5-metre-long, 52-kilogram torpedo-shaped vehicle is under evaluation by the federal government’s Institute of Ocean Sciences (IOS). Driven entirely by a variable buoyancy system instead of a propeller, it needs no mother ship for tethering or support. The evaluation project is a formal collaboration between Fisheries and Oceans Canada and the Canadian Centre for Ocean Gliders (CCOG).