The great Colombian debate about Pablo Escobar s cocaine hippos has come to an end.

The late drug lord famously owned four hippos that procreated with abandon after he was killed in 1993. For the past 30 years, officials have pondered what to do about the animals there are now about 170 of them and their destruction of the local ecosystem. Now, theyve decided on sterilization .

We are in a race against time in terms of permanent environmental and ecosystem impacts, Susana Muhamad, the environmental minister of Colombia, told The New York Times in a statement Saturday .

Officials say the expansive hippo population has roamed the countryside unregulated for years, and their numbers could skyrocket to 1,000 by 2035. While the World Wildlife Fund designates them as vulnerable , the herbivores have no natural predators in the area.

Colombian officials have thus decided on a three-pronged plan to sterilize, euthanize or relocate the hippos. They announced Friday that four have already been sterilized. Officials reportedly now plan to tranquilize and surgically sterilize 40 hippos per year.

Escobar, who founded the Medelln Cartel and dominated the 1980s cocaine trade, is thought to have imported the first four hippos from a breeding center in Dallas . Their descendants became a highlight, alongside other wildlife, of his Hacienda Npoles ranch .

While some researchers believed the hippos could restore the local ecosystem , the animals were eventually deemed an invasive species in the region. One of them was killed after being struck by an SUV on a highway near the ranch earlier this year.