Wildlife officials are alarmed at the number of manatees that have died in Florida just in the first few months of this year. According to The New York Times, it’s more than 10 percent of manatees compared to the number of deaths in all of last year. There were at least 761 manatee deaths between January 1 and May 28, according to a new Florida Fish and Wildlife Conservation Commission report.

Last year, the total was 637. Experts point to the increasing lack of sea grass in the Indian River lagoon which is a 156-mile estuary on the coast of Florida. Wildlife officials say the lagoon has lost more than 10,000 acres of sea grass, and the water quality has been polluted by runoff from sewage and septic leaks which grow algae that kills the sea grass.

“If there is no sea grass for the manatees, there is also no sea grass for other species,” Jaclyn Lopez, Florida director for the Center for Biological Diversity, said. “The fact that manatees are dying from starvation signals there is something very wrong with the water quality.”

Sea grass is similar to seaweed and grows underwater. It is the main food source for manatees, according to NBC2 News.

Manatees had previously been considered “endangered” by the U.S. Fish and Wildlife Service. However, a politically charged decision four years ago changed the manatee’s conservation status to “threatened” instead.

Aside from manatees, scientists also have other concerns – they say the impact of algae blooms may also affect other marine habitats.