Last November, a small majority of Mainers voted to approve the legalization of cannabis in the Pine Tree State, allowing residents to legally purchase cannabis or grow their own. But the U.S. Coast Guard has just informed state residents that cannabis legalization only applies to dry land.

Federal law applies to major navigable waterways in the country, which means that both recreational and medical marijuana are illegal on boats traversing these waterways. The Coast Guard patrols the waters off the Maine coast on a daily basis, and routinely boards both commercial and private boats for safety inspections.

Lt. Jeff Bryant, Coast Guard Chief of Enforcement said that if officers discover marijuana “in the course of a boarding in a US navigable waterway, we will have to confiscate the marijuana and issue a civil penalty to its owner.” Bryant said that anyone traveling by boat, even from a coastal city to a nearby island, should avoid carrying any marijuana on them.

Bryant noted that the Coast Guard is not specifically looking to bust individuals with pot, but they are required to enforce the law if they discover cannabis during a routine inspection. “Our primary purpose out on the waterways is for the safety and security of the boating public,” he said. “We can’t pick and choose which federal laws we enforce and marijuana remains illegal under federal law so if we do come across it we will enforce it.”