Howard is the last of a group of four dolphins brought to the mall from Florida in 1985. Gary died in 2001 and Maria in 2000. As well, two of Maria's calves and three of Mavis' died.
Dr. John Nightengale, head of the Vancouver Aquarium, says the malls should review its care practices.
"We would urge them to do a review, bring in some outside people and bring in the expertise to review all their systems and programs as part of that process," he said.
Some experts are concerned that if Howard is left in the tank by himself he won't survive for long. Dolphins are social creatures, and Mavis had been his mate.
Nightengale says his aquarium or another one specializing in dolphins could help the mall figure out if it's doing anything wrong.
Gary Hanson, manager of the West Edmonton Mall, says he can't comment on what will happen to the dolphin program because he hasn't discussed the situation with staff.
He says the dolphin trainers are emotional and he doesn't yet want to talk to them about Howard.
Mall officials have said in the past that they won't capture any more dolphins to replace those who die, but they didn't rule out bringing them in from other aquariums.