Mexican drug cartels are expanding their reach into wildlife crime. They’re strengthening their hold on the country’s legal fisheries and using them to launder illegally caught marine animals, according to a soon-to-be released report by the Brookings Institution.

The cartels previously had been linked to trafficking of marine species such as totoaba, as well as rosewood, a timber that is coveted for high-end furniture and musical instruments. But the Washington, D.C.-based think tank’s report indicates that the crime groups have recently stepped up their trafficking of wildlife species, often to China. In exchange, the cartels sometimes receive chemicals that can be converted into fentanyl or methamphetamine.

“Instead of selling lemonade, it’s like they will be selling lemons and sugar to the cartels