According to Florida Today
, this syndrome, which claimed its latest manatee victim, July 4, first began killing seacows in Brevard County during mid-2012 when seagrass began to significantly die off, causing the seacows to change their diets.
Experts believe that between 2012 and 2015, 158 Indian River Lagoon manatees perished due to the syndrome, reports the Tampa Bay Times.
The seacows in the Melbourne area have been eating seaweed that has drifted in from the Indian River Lagoon. Martine deWit, a biologist from with the Fish and Wildlife Research Institute told Florida Today
that the nutritional value of the seaweed itself might not be the problem, but that there could be a different composition of the diet that puts the animal in danger.
The seacows have also been eating more drift macroalgae, which at first scientists pinpointed as the cause of death for the manatees. According to Florida Today,
scientists thought that these macroalgae blooms could have a toxin that messed with the manatee's nervous system and harmed its ability to surface in the water, causing them to drown.
But no evidence of typical algae toxins have shown up in testing. Their bellies were full of a red seaweed called gracilaria, which deWitt told the Tampa Bay Times
that the new change in diet mixed with the algae blooms is probably what killed them.
She also said that there wasn't any pattern to the deaths of the seacows, and that the majority of manatees were able to withstand the diet change.
Due to the resurgence of a strange syndrome that's left biologists baffled, nine dead manatees have been found near Melbourne, Florida, since May.