Manatees are again dying from a mysterious syndrome in Florida's Indian River Lagoon.
Florida Today reported Saturday that at least nine manatees have died since May. The syndrome first appeared in 2012 and is tied to them eating stringy seaweed instead of their usual diet of seagrass, which has been dying off because of microalgae blooms.
Researchers are stumped because the majority of manatees that eat the seaweed don't seem to be affected by it.
Biologist Martine deWit of the Fish and Wildlife Research Institute said the suspicion is that something about the change in diet makes some manatees susceptible to complications.
Since 2012, more than 100 manatees have died in the Melbourne area because of the syndrome.
Tests rejected a hypothesis that a toxin that affects the seacows' nervous system was hampering the marine mammal's ability to surface, causing it to drown. No toxins were detected.
``It appears that the nutritional value itself may not be a problem,'' deWit told the paper. ``The suspicion is that there is a different composition of the diet that makes the animal susceptible to complications.''
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But mo re tests are needed to figure out what the connection is.
``Whatever causes their gut (to get) upset makes such a chain reaction in the body that they acutely react to that,'' deWit said. ``We have lots of pieces of the puzzle that we're putting together ... The majority of the animals are eating this and survive.''
