Exploring depths of Everglades for "River Monsters"

Jeremy Wade on the swimming success of "River... 05:27

This piece originally aired on April 2, 2015.

The seventh season finale of Animal Planet's wildly popular reality series "River Monsters" airs Monday night. In the past six years, "River Monsters" host Jeremy Wade has traveled the globe to catch everything from deadly stingrays to man-eating piranhas, reports CBS News' Michelle Miller.

He's fished remote waters all over the planet but has never explored the depths of Florida's Everglades region -- until now -- and as fans of his program know, his excursions are never dull.

"People say to me, it's a fishing show; it's not," Wade said. "It's really a detective story. Each episode is a detective story. It starts with some unlikely sounding tale of somebody being bitten on the leg or pulled under or whatever, and then at that point, you've got people's attention, and it's then an investigation to find out what it is."

He said he's nearly died "a couple of times." He's suffered malaria and survived a plane crash.

The thought of one day hanging up the act has not been lost on him.

"I have thought that," he said. "I think in my case, it's the curiosity that overrides that and the sense of achievement that you get when something's difficult."

On television, he's achieved star status, but he doesn't have a problem teaching people to fish.

"I think some people when they fish, they just sit down the first place that's available," Wade said. "But the way we do it, it has to be very focused and very targeted."

Wade said a combination of luck and preparation help put fish on the end of his line. But some fish he's found in the Everglades are not meant to be there.

"You've got all these weird, invasive species that are turning up, people release things out of fish tanks or whatever," Wade said. "In an ideal world, you don't want creatures where they shouldn't be because there's always unintended consequences."

Biologist Joel Trexler, who tracks the health of the fragile Everglades ecosystem, said there are a large number of new species in the area.

"Probably as many as any region in the United States," he said.

When an invasive species comes into an area like the Everglades, it can have a negative impact.

"It can displace native species," Trexler said. "I think most importantly, it can change the way the food web works, and frankly, we don't really know enough about what those species are doing and their impact."

Wade takes pride in teaching moments like that throughout his show, but for most fans, it's all about the adrenaline.

"One of the things that we're doing new this season is I'm going more underwater now ," he said. "Normally, you can't see anything in fresh water, but in certain situations you can."

He's even picked up the tail of a crocodile underwater.

"My heart was beating a little bit faster than normal," Wade said.

The swamp animals may give him funny looks every now and then, but he's perfectly happy with the way everyone else sees him.

"The great thing about freshwater fish is most of them are incredibly ugly, a lot of them are, so no one can fail to look good next to some of these things," Wade said.