Selected female bison are being injected with a vaccine that will prevent them from getting pregnant. Officials call it a non lethal way to help control the booming bison population.
"It doesn't alter their behavior, the males and females will still mate with each other. They just won't give birth to calves. It is affordable. It is not something that works its way through the food chain," said Dr. Ann Muscat with the Catalina Island Conservancy.
The current bison population is about 150.
The vaccine will be given annually, but it is reversible. So if the conservancy wants to increase the bison population, it can.
