ALAN BERNER / THE SEATTLE TIMES
A sand tiger shark swims by as staff divers David Todd, left, and GiAnn Eastman, far right, flank Paul Tosch and Denise Whitaker during a preview of Tacoma's Point Defiance Zoo & Aquarium's Eye-To-Eye Shark Dives exhibit, which opens to the public on Friday. Certified divers can register at pdza.org, which lists costs and requirements. The exhibit also is an educational program on sharks. According to zoo officials, sharks kill about 12 humans a year, while humans kill about 38 million sharks just for soup.