Results from a necropsy show that Chester, a false killer whale that died that the Vancouver Aquarium last week, had a bacterial infection found both in wild and captive cetaceans.

In an email, the aquarium said it’s believed the three-year-old false killer whale died of erysipelas, an infectious disease. Helen, a 30-year-old Pacific white sided dolphin and the only remaining cetacean at the Vancouver Aquarium, is being treated proactively with antibiotics.

The aquarium has faced criticism from those opposed to keeping cetaceans in captivity, particularly after its beluga whales Aurora and Qila died within nine days of each other in November 2016. In May, the Vancouver Park Board approved a ban on bringing new dolphins, whales and porpoises into captivity.

Meanwhile, the aquarium also announced it will acquire two young walruses from Aquarium du Quebec in Quebec City. The animals, named Lakina and Balzak, were delivered days apart in the spring of 2016. It’s believed they are the first live, full-term walruses born in captivity in Canada and may arrive in Vancouver before Christmas.

With files from The Canadian Press