Two Storybook Garden seals die while in transit to St. Louis Zoo

Two harbour seals are dead, one is sick, and no one has any answers.

At a press conference in London, Ontario on Sunday, Storybook Gardens officials announced the death of two of their four harbour seals while in transit to their new home at the St. Louis Zoo.

"This is a deeply sad day for Londoners and all those people who knew and loved our Storybook seals," London, Ontario, mayor Joe Fontana said at the news conference.

Seals Nunavut and Atlantis died en route of unknown causes. Cri Cri is in critical condition. The fourth seal, Peanut, arrived alive and well.

John Riddell, Storybook's manager, said that a veterinarian examined the animals before they left London. Each was found to be in good condition. They were transported in an air-conditioned truck and were checked on frequently.

[ Related: High Park Zoo avoids closure thanks to donations ]

"An investigation is underway," Bill Coxhead, London's director of Parks and Recreation, assured Londoners.

In January, London's Storybook Gardens announced the end of its 55-year-old zoo.

As part of its business plan, one that couldn't allocate enough funds to bring the zoo up to current standers, the family-friendly destination would relocate its remaining exotic animals to facilities that could better care for Storybook's harbour seals, lynx, beavers, otter and birds of prey.

The only live animals to remain at Storybrook Gardens are those found in the Old MacDonald's Farmyard area: sheep, goats, miniature donkeys, rabbits, ducks, chickens and a dog.

"We have wonderful opportunities to finally relocate these animals to more suitable habitats where they will receive the very best of care in naturalized settings," Ross Fair, Executive Director of Community Services, said in a statement. "In the past several days, the civic administration has been presented with an extraordinary opportunity to move the remaining four harbour seals to the new exhibit at the St. Louis Zoo, Missouri at no cost to the City."

Fair called the St. Louis Zoo "one of the best facilities in North America," where the seals could live in an $18-million "state-of-the-art pool."

(Storybook Gardens had received numerous complaints over the years that their pool was inadequate for their seals, with it being too small and too shallow.)

Unfortunately, two of the four seals didn't live to swim in such luxury. It will take several weeks before the official cause of death is determined.

"It's terribly emotional for us. We wanted the best for those animals. We continued to feel that the right move was to move them," Julie Woodyear of Zoocheck Canada, the wildlife protection agency that funded the move, told CBC News. "I don't know what happened during transport but I will find out."

[ Related: Race to save the devil Down Under ]

"We do everything we can when transporting animals to ensure their safety and comfort, but there is always some risk inherent in any animal transport," Dr. Jeffrey Bonner, president and EO of the St. Louis Zoo, said in a statement.

In 2007, Hazina the hippo died after transit from the Denver Zoo to the Calgary Zoo, a situation called "very unusual" by Lynn Kramer, Denver Zoo's vice-president of biological programs.

The story sounds eerily similar:

"We're all scratching our heads [as to] what we'd do differently right now," Kramer told CBC News at the time. "The normal process is to stop every few hours and examine the animal, which was done."

Calgary Zoo's veterinarian, Doug Whiteside, assessed that Hazino had been lying in one position in the crate for too long, damaging her leg muscles, which subsequently lead to a release of toxins into the bloodstream.

In an article for the Smithsonian Zoogoer, writer Valerie May describes the challenges and months-long prep involved in transporting zoo animals:

"Behind the scenes of each animal move is a complicated scenario involving dozens of steps. On average, at least two months of planning goes into each animal transport. Each scenario is unique, depending on the animal and the circumstances of the move. Small animals are more delicate; large animals present greater logistical challenges. Amphibians require a specific water temperature."

Here's a current transport guidelines for seals, according to the Convention on International Trade in Endangered Species in Wild Fauna and Flora.

It's zoos' catch-22: Moving animals can be dangerous to their health. Keeping animals at facilities not equipped to give them the best care can be even more dangerous.