Discovered a more detailed press release about the matter on the Toronto Zoo website.
The Aquarium du Québec and Toronto Zoo working together to combine their expertise and experience for two iconic polar species | Media Room | Toronto Zoo
Lakina and Balzak are returning to Aquarium du Québec in November 2019. Arnaliaq and Lakina are expected to move to the Toronto Zoo in 2020 once modifications to the polar bear habitat are made. Balzak will remain at Aquarium du Québec with his father Boris.
Eddy will return to Aquarium du Québec in early 2020 once renovations to the polar bear habitat are complete. Hudson and Humphrey from the Toronto Zoo will join him. Taiga will move to the Toronto Zoo to join resident female polar bears Aurora, Nikita, and Juno.
I find it rather odd that the Toronto Zoo will have polar bears and walruses residing in same exhibit complex, but, then again, the concept of these two species living in close proximity in a captive setting isn't too far-fetched. The Eismeer, at Tierpark Hagenbeck, houses polar bears and walruses in the same exhibit complex. To make it appear as though both species share the same habitat, the Eismeer utilizes the immersion exhibit design by hiding the trenches which separate the polar bears from the walruses.
Photo: Stefan Hesse
Der Chef, der Pantoffelheld, die Zicke: Wer ist wer in Hagenbecks Eismeer? - Hamburg - Bild.de
The Toronto Zoo will have a similar exhibit design as the coastal themed habitat conceals the moat of the tundra themed habitat. It'll be really cool to see the Toronto Zoo have the walruses in the coastal themed habitat while the polar bears are in the tundra themed habitat behind.
Photo: animalman0341
Polar Bear Exhibit - ZooChat
It's very plausible that the Toronto Zoo is anticipating Arnaliaq to reproduce while residing at the Toronto Zoo as the press release states
"[the] change [between the walruses] will ensure better reproductive management and allow for a study of the maternal bond that exists within the species."
Since Lakina has been weaned from her mother Arnaliaq, the maternal bond, if one still exists, will not be as strong as the bond between a newborn calf and its mother. Therefore, if Arnaliaq breeds with Boris at Aquarium du Québec and moves to the Toronto Zoo pregnant, the Toronto Zoo will be able to conduct
"a study of the maternal bond [in walruses]."
Also, if Arnaliaq does become pregnant and gives birth to a viable calf, it'll be the first walrus calf to be born at the Toronto Zoo!
The Cochrane Polar Bear Habitat has announced that Taiga is showing signs of a potential pregnancy.
Potentially pregnant polar bear showing denning behaviour in a natural captive environment - Polar Bear Habitat | Facebook
With Taiga moving to the Toronto Zoo in the foreseeable future, and possible cubs on the way, it questions whether Taiga will remain at Cochrane Polar Bear Habitat for some time or be transferred to the Toronto Zoo sooner rather than later. Since Taiga isn't moving to the Toronto Zoo until Hudson and Humphrey have been transferred to Aquarium du Québec, it's highly likely that Taiga will be moved once her cubs are mature enough. Of course, this is based on the assumption that Taiga is pregnant so if she isn't, she will probably be transferred shortly after Hudson and Humphrey's departure for Quebec.