The stillness of a misty February morning is broken by a splash as diver Tony Mulhall plunges into the frigid waters off British Columbia’s North Coast. Fighting bone-chilling temperatures, strong currents, and the all-too-real possibility of kelp entanglement, he swims down to the rocks below in search of Strongylocentrotus droebachiensis and Strongylocentrotus franciscanus -green and red sea urchin.