A proposal to shoot the last herd of purebred bison in Yellowstone National Park with vaccinated “biobullets” was just rejected by park managers this week. The vaccine-toting biobullets were initially proposed as a way to protect the dwindling bison population, which is susceptible to brucellosis, a bacterial infection that affects bison and cows. The plan was rejected largely because of its cost of $9 million, but also due to the impact that prolonged interaction with humans could have on the herd.
Yellowstone National Park currently has a population of only 4,600 wild bison, and park managers estimate that half have been exposed to brucellosis. The infection can cause bison and cows to miscarry, further decreasing their numbers. Area cows may also be exposed to the virus, which has led to a rift between livestock advocates and wildlife conservationists.
Yellowstone proposed the biobullets as a solution to brucellosis. The vaccine-packed bullets could cut disease rates by 35 percent over the course of 30 years. Experts would have to deliver the vaccines once a year for the thirty years, shooting each bison in the park with the vaccinated bullets.
Although the return seemed promising, park managers have decided against biobullets, citing issues with the astronomical cost, potential side effects, effectiveness, and possible behavioral changes that being shot once a year could bring. For the time being, the park will continue with the challenging task of capturing and treating infected animals.