Colombia is to cull some of the 166 hippos descended from a herd owned by drug lord Pablo Escobar.
Escobar imported the animals for his private zoo at hacienda Napoles in the 1980s.
The animals had been left to roam after Escobar was killed in a shootout with police in 1993.
After years of trying to control the population, which massed around the Magdalena river, the Colombian government said it will now sterilise some of the animals while a small number will be killed.
“We are working on the protocol for the export of the animals,” Environment Minister Susana Muhamad told local media.
"We are not going to export a single animal if there is no authorisation from the environmental authority of the other country.”
She said the first stage of the plan will be the surgical sterilisation of 40 hippos per year and this will begin next week.
The government has also said some of the animals will be transferred to zoos abroad after the population boomed due to the lack of predators, and the swampy Antioquia region which provides perfect conditions for the African animal to thrive.
Such was the increased population that the hippos were declared an invasive species last year.
If the government didn’t act, estimates predicted the population could rise to 1,000 by 2035.
Escobar had risen to be one of the most powerful drug dealers in the world at the time of his death.
It is thought he amassed a fortune worth £25billion by smuggling drugs into Miami and the southern United States.
He was shot dead on a rooftop in his hometown of Rionegro on December 2, 1993 as he tried to evade police.
