Overpopulation of cats is a major issue in Rapid City, says the local animal shelter executive director.

"If 70 percent of a population is spayed or neutered, the population can be considered stable. Right now in Rapid City, dogs may be at around 60 percent, but I doubt if we are even at 10 percent with cats," Humane Society of the Black Hills Executive Director Phil Olson said.

Given this challenge, the shelter has taken a proactive approach to the cat overpopulation issue with a "surgery suite on wheels," the spay/neuter mobile unit. The unit was originally used to spay and neuter shelter animals only, but Olson has brought it into the community by hosting events at the shelter during which stray or free-roaming cats can be spayed or neutered free of charge by volunteer veterinarians.

"The first clinic was in July, and we had 15 cats," Olson said. "The next one was at the end of September, and 46 cats were spayed or neutered."

The next spay/neuter clinic is from 8 a.m. to noon Nov. 11 at the shelter, 1820 East St. Patrick St., and Olson hopes to have an even bigger turnout.

"An animal shelter is a little bit like closing the barn door after the cows get out," he said. "As much as you prune the branches, you've also got to get to the roots once in a while. The spay/neuter clinics work at the root of the problem, not just at the symptom level." For more information or to let shelter staff know you are bringing in a cat, call 394-6906.