"Underwater Puppies" takes adorable to new depths

Few things in life are cuter than a puppy.

An innovative photographer created a photo book featuring wide-eyed pooches in the water, and the pictures are just part of the appeal, CBS News correspondent Ben Tracy reports.

Seth Casteel calls himself a lifestyle pet photographer, and his first book "Underwater Dogs" was a best-seller in 2012. So he figured "Underwater Puppies" would be an inevitable encore.

He said the dogs love being the subjects of his photo shoots.

"They are thinking, 'I'm having the time of my life right now.' They feel wild again," Casteel said.

For Casteel, this is not just fun and games. He wants to remind pet owners how vulnerable dogs are around water.

"You know this is such an important message, to let people know that they should absolutely teach their dogs, whether it be puppies or adult dogs, how to get out of the pool," Casteel said.

It's estimated that thousands of pets drown each year in swimming pools.

So Casteel spent six months traveling through 13 states, teaching dogs of all ages to swim toward the steps. He lures them into the pool with a game of fetch and quickly snaps his shots with an underwater camera.

He has taken more than 100,000 pictures with 1,500 puppies. At times he spent 14 hours per day in the pool.

Casteel said his line of work actually "started with cats," using his photography to help abandoned kittens find homes.

He then went into business shooting pet portraits, and was hired to capture a dignified pose of a King Charles Spaniel named Buster. But buster had a few thoughts of his own.

"This little dog loved the pool, so he started jumping in. And I thought, 'wow, that's magnificent,'" Casteel said. "The owner was just so upset because she wanted some really fabulous dry shots of Buster with his crazy hair blowing in the wind, and I said, 'Hold on a minute, you know, this is what Buster likes to do. Let's see if we can make it happen.' Left, bought a little point-and-shoot underwater camera, took a couple snapshots, got home and was like, 'Wow, I gotta see what's going on with this underwater dog stuff.'"

Most of the puppies Casteel captures in his photos are rescues. He hopes their wide-eyed charm reminds people to visit shelters when looking for a pet.

"What's next is 'Underwater Babies,'" Casteel said. "The other day I photographed 60 babies in a day. And I had such a blast working with these babies and watching them learn the importance of swim safety. It's awesome, man!"

Casteel is just beginning to scratch the surface of doing business underwater.