LOGY BAY, N.L. -- Daryl Jones, also known as The Seal Guy, laughed when asked what surprises him most about working with harp seals at the only research site of its kind in the world.

"When the seals do what we want," he said before hand-feeding his charges a snack of herring at the Ocean Sciences Centre in Logy Bay, N.L., just north of St. John's.

"They're smart but they're very independent. They're similar to cats."

Jones is an aquarist who starts many days with a "whisker greeting" as the two females, Babette and Deane (pronounced DEE-nee), bump his hand with their noses.

Tyler is the third seal living in two large outdoor seawater-fed pools with surrounding decks and a smaller tank that looks a bit like a seal bathtub.

"Tyler just looks at you and says: 'You've got no fish for me?' "

Deane is the daughter of Babette -- affectionately called Babs -- and Tyler. She was named for Deane Renouf, the late marine mammal ecologist who helped found the research program in the 1980s.

Babs, believed to be about 32 years old, was captured in 1989 from the Magdalen Islands in the Gulf of St. Lawrence. She is the globe's first harp seal to give birth in captivity, Jones said.

Tyler, 25, was captured from the same place a year later as a white coat pup. Deane is now 13.

Harp seals in the wild typically have a life span of about 35 years. Mature males and females both reach around 169 centimetres in length and weigh about 130 kilograms.

"Marine mammals in captivity live much longer than their wild counterparts," Jones said.

But it's not known why two other seals, Jamie and Lenny, died at the facility within months of each other in October 2013 and February 2014, he said. Jamie was 19 and Lenny was 13.

"We did a necropsy and could not find any obvious cause."

Jones clearly loves his work and the popular seals that over his 17-year career at the centre have become "like family."

"They are research animals, they're public education animals but you live with them and you care for them and they're part of your life."

It's the only place in the world where harp seals, named for the shapes of their black markings, live in what scientists call an "enrichment environment."

Researchers over the years have studied their behaviour, diet, physiology, even their ability to be shown one object, then find its match when shown multiple options -- for a fish reward, of course.

The seals are also local celebrities. They draw about 20,000 visitors a year, especially during the public education program run each summer.

Jacky Peddle watched from the public observation deck on a recent morning as Jones worked with the seals. She has brought her two sons to see them for years.

"The staff really know their stuff and love to share their knowledge with the children."

People always ask Jones about the seals first, he said with a smile.

"Nobody says: 'How are you, Daryl?' They say: 'How are the seals, Daryl?' I used to have a life."