Valerie Morgan, who runs the Animal Rez-cue shelter in the Kitwanga area, helped organize the mass spay-and-neuter campaign.
She says dogs and cats are often abandoned on reserves after they grow out of the "cute phase."
"They start out as cute little puppies. About three months into it, they're not so cute anymore," she said.
The dogs, left to fend for themselves, go feral and become a health and safety concern that only grows with time.
"So, then that puppy ends up feeding itself, fending for itself, digging in garbage. Some of them aren't healthy because there's a lot of inbreeding that goes on. So then they have health issues," she said.
"Before you know it, you have a lot of male dogs that are aggressive, they're running in a pack."
Morgan says in the past, packs of wild dogs were rounded up and shot, which is how some reserves still manage the populations.
She hopes the example of this week's spay-and-neuter campaign for Kitwanga, Gitsegukla and Gitanyow will encourage other reserves to seek other solutions.
"The communities are really involved in this project, which is really rare to see the whole community come together like this for an animal," she said.
By the end of Friday, Morgan expects the three veterinarians who donated their time will have spayed or neutered over 120 animals out of the Gitwangak Community Hall.