In the western Caribbean Sea, where the water glows sapphire and reef wiggles along the sand, Jason Dimitri was seconds away from death.

Late last week, Dimitri was plunging a spear into that reef, hunting the invasive species lionfish, when a Caribbean Reef Shark “came out of nowhere” and attacked him. Seventy feet of water separated Dimitri from the surface, and he began to swim upward, stabbing at the large shark as it repeatedly charged toward him.

He caught the whole thing on a GoPro 3 camera, and posted it on YouTube. It quickly gobbled up more than 400,000 pages views in a few days.

“The Cayman Islands is where I learned to dive,” he said in the posting. “I love this place and will continue diving here for the rest of my life. In no way did this encounter discourage me from getting back into the water.”

He says there are too many lionfish in the Caribbean to stop hunting them. According to the National Centers for Coastal Oceans Science, the invasive species has spread like a contagion throughout the Caribbean. Today, there are as many as 1,000 lionfish per acre. Their density can suffocate vital species to the region’s ecosystem, like snappers and groupers.

“I want to make it clear that I am hunting lionfish to help protect the reef from the destruction they cause. The shark was acting in his natural environment. I have no ill will toward him.”

For a another fish story, see A fish called robot