Transcript for Teacher Films Sharks for Class
The circumstances were terrifying at 32 year old American was scuba diving in Australia over the weekend. When his friends suddenly saw the ocean -- break into a storm of bubbles. The diver was killed in the culprit. A great white shark possibly responsible for two other fatal attacks the last two months. Such attacks only -- -- the fearsome wrap of sharks but some marine biologists say. The bum -- tonight ABC's John Berman goes into the war. Okay. Like armor teeth like -- eyes -- -- we -- the ocean's top predators but nothing on earth is tougher. Well almost nothing. -- -- School teacher -- -- definitely -- high school. It took effect it will. Valerie -- a biology teacher and Jensen beach Florida Sweden's with sharks beat. Scary looking jump. Five. That's a lot of faith that putting someone you've just met -- We. We join Valerie and her husband -- New Mexico -- on a boat with them in motor one miles out to -- What might be the world is used shark feeding ground. -- -- -- Last daddy starts let you know -- one scary start this wanted to give the largest fish. It's an amazing. Just sit there so gentle that agenda but. And -- -- sharks for more than incredible the of the largest pension -- measuring up to 41 and a half feet weighing 47. Thousand pounds -- big but. -- -- basically only eat plankton and tiny initiate. Only reason I agreed to -- snorkeling which obviously I'm not very good. And we're chasing. They think that we. -- that they really had to settle. Higher than the fact that company and -- like -- Jason. So what it looks like -- -- to swallow me whole it's just a coincidence and it within -- that He swimming dinosaurs literally. Their movements through the water needless to say the experience is all -- liar. -- -- three billion don't know any. Hillary has been diving for almost four years He seized more than a hard being the lesson plan. -- educational philosophy. With a high school teacher doing the video of the New York City. -- -- Six. Everything I didn't -- that the. Her husband GE villains all these underwater encounters which they do all of their old guy by the way now whale -- actually follow either plankton and balloons or spot. -- -- -- -- active class you'd better believe when your teacher swim with sharks you listen to sharks give -- street. But pretty serious yeah typically the is is -- true labor of love for Valerie look for education and yes sharks. Be scared of the middle. I lived it. Basically go in with any type of -- Start here now. In fact He didn't want to go public works around the world -- creatures which it ruled that. Don't nationalist or dwindling. That's the message that -- please to plants in three day. My dream. Would be that we conserve them that they -- here for generations. And right now because of what we're doing. With the shark and trade industry and -- depleting them out millions of sharks every year at this point. Recent attacks on the coast of Australia that He says she never had a run in where He -- close call with the shore. We don't want -- -- -- she said its effects scientists say dogs killed more people every year insurance the. I -- smiling. And attacking and it's just Lebanon's flag like all of the shark is smiling He. Sometimes -- and attractive. -- It's no surprise Valerie was -- -- counties -- road here last year. I love this -- When the -- goes on in the kid's eyes and they say wow. I keep believing in god are you kidding me -- -- and this is incredible. We should all had teachers willing to reef sharks for us. You're not erected that it makes a metaphor here but it again -- like you get -- chum in the water absolutely. Absolutely and bring in a man this is -- the sharks at the sharks a shark bait -- -- -- -- and is working hard and I'm John Berman for Nightline off the coast of Cancun in Mexico.
This transcript has been automatically generated and may not be 100% accurate.