(AP Photo/Fernando Llano)PUERTO MORELOS, Mexico -- Swaths of seaweed are blanketing the beaches and coastlines of the Caribbean and Gulf of Mexico, suffocating shorelines and snuffing out marine life while spooking visitors in areas that depend heavily on tourism. The Great Atlantic Sargassum Belt has been growing since 2011, dumping an increasing amount of seaweed along coastlines in the Caribbean and Gulf of Mexico. Sargassum levels in the Caribbean reached record levels in June, while the amount present in the Gulf hit 5 million metric tons in June, nearly double last year’s record, according to the University of South Florida. Much of the record sargassum reported last year ended up along Puerto Rico’s coastline, prompting the governor to declare a state of emergency. In the U.S. Virgin Islands, people are walking up to 25 feet (seven meters) on mats of seaweed before even reaching the water, according to Amy Dempsey, an environmental consultant.