Are there any large aquatic mammals in Zootopia?

According to the artbook "Art of Zootopia", it was simply too difficult for the film's concept artists to work out how to include large aquatic creatures (and other non-mammal animals) in the city. So they were just gently airbrushed out of the picture.

The team spoke with zoologists, animal behavior specialists, and scientists who study animal evolution. Based on what they discovered, the filmmakers decided to limit the film’s animals to mammals, although “reptiles and birds and other animals do exist on this planet. We just don’t go to those continents,” says screenwriter and co-director Jared Bush. This constraint led to an “aha!” moment that became a central tenet of Zootopia—that mammals are divided into two groups: predators and prey, and prey animals outnumber predators ten-to-one.

They show hippos, which are large aquatic mammals. Further we see that the hippo commuters use a special water-filled "subway" that presumably could be used by other aquatic mammals.

I believe zootopia is like a regular zoo. If you go to a regular zoo, you can see lions, elephants, apes, birds, etc... , you don't see whales or dolphins only in an Aquazoo/park which Zootopia isn't. If you look at the Zootopia Disney Wiki you can see the cast here and all the animals that are in the movie:

• Ginnifer Goodwin as Judy Hopps, a rabbit
• Jason Bateman as Nick Wilde, a red fox
• Idris Elba as Chief Bogo, a cape buffalo
• Jenny Slate as Bellwether, a sheep
• J. K. Simmons as Mayor Lionheart, an African lion
• Nate Torrence as Clawhauser, a cheetah
• Shakira as Gazelle, a gazelle
• Bonnie Hunt as Bonnie Hopps, a rabbit
• Don Lake as Stu Hopps, a rabbit
• Tommy "Tiny" Lister as Finnick, a fennec fox
• Alan Tudyk as Duke Weaselton, a weasel
• Maurice LaMarche as Mr. Big, an arctic shrew
• Phil Johnston as Gideon Grey, a red fox
• Raymond S. Persi as Flash, a three-toed sloth
• Tommy Chong as Yax, a yak
• Octavia Spencer as Mrs. Otterton, an otter
• Jesse Corti as Manchas, a black jaguar
• Katie Lowes as Dr. Badger, a honey badger
• John DiMaggio as Jerry Jumbeaux Jr., an African elephant
• Peter Mansbridge as Peter Moosebridge, a moose
• Mark "Rhino" Smith as Officer McHorn, a rhinoceros
• Kristen Bell as Priscilla, a three-toed sloth
• Leah Latham as Fru Fru, an arctic shrew
• John Lavelle as Mouse Foreman
• Rich Moore as Doug, a ram
• Byron Howard as Bucky Oryx-Antlerson, a kudu, and Travis, Gideon Grey's weasel friend.
• Jared Bush as Pronk Oryx-Antlerson, an oryx
• Josh Dallas as Frantic Pig Gita Reddy as Nangi, an elephant
• Fuschia as Drill Sergeant, a polar bear
• Zach King as a wolf