There’s no backup boat out here—just lungs, fins, and focus. Every dive for dogtooth or wahoo is a risk. The pressure’s real.

An endless stream of shark movies has swum into theaters in the more than 50 years since Jaws, and the scariest shark movie since Steven Spielberg’s 1975 masterpiece just took a bite out of HBO Max.

A routine day of shark diving and underwater treasure hunting suddenly turned into a rescue scene. Police and paramedics attempted CPR on a drowning victim just metres from where I was diving, with a ...