Two beloved sea mammals — manatees and bottlenose dolphins — suffered record numbers of deaths this year, baffling scientists and rightly raising concerns about the health of the waters surrounding Florida. Surely, what we humans dump into our waters must share the blame along with natural causes.
So far, 803 manatees have died in 2013, well above the 392 deaths in 2012. The 800 deaths are about 16 percent of the state's estimated population of 5,000 manatees total. A massive bloom of Red Tide algae along the southwest coast killed 276 manatees early in 2013 — the worst Red Tide toll on sea cows ever recorded. But an unidentified illness is killing manatees in the Indian River Lagoon on Florida's Gold Coast. So far, 117 have died there since July 2012.
The only good news is that manatee deaths from encounters with boats are down, to 71 deaths, from last year's 81. But back to Indian River Lagoon. The deaths of dolphins and pelicans have also hit unprecedented numbers in the estuary. Scientists are stumped, but there's little doubt that the summer's flood-prevention diversion of polluted water from Lake Okeechobee into the St. Lucie River and Indian River Lagoon and the Caloosahatchee River on the West Coast must be taken into account. The nitrogen-laden outfall deadened the St. Lucie and created an enormous environmental crisis in the lagoon.
Meantime, nearly 1,000 dolphins — eight times the historical average — have washed up dead along the Eastern Seaboard, from New York to Florida. Nearly 80 dolphins whose permanent home was (here it is again) the Indian River Lagoon have died, while another 233 died in the northern Gulf of Mexico. Many of the Eastern Seaboard dolphins’ deaths were from morbillivirus, a disease deadly for dolphins. The last outbreak of the virus was 25 years ago.
Again, the dirty water from the U.S. Corps of Engineers’ diversion of lake water during hurricane season, along with other urban pollutants, could be contributing to the dolphins’ deaths in the lagoon. And in the Gulf, lingering effects of the 2010 BP Deepwater Horizon oil spill could also be a culprit in dolphins’ demise there.
But scientists can't explain why the morbillivirus has cropped up again. They theorize that one reason for so many deaths is that many of the dolphins weren’t alive during the first viral outbreak and therefore weren't immune. And the range of dead manatees is also disturbing. In all, 173 breeding females died, which could impact the future of the manatee population.
Federal and state officials have only begun to address the nearly annual diversion of lake water to the east and west coasts. It’s too dirty now to send south into the Everglades, where it belongs. The joint federal-state Everglades cleanup plan will eventually restore the rightful flow, but that’s years away, giving little relief to the St. Lucie River and lagoon soon. But the state has earmarked nearly $3 million for some cleanup work along the St. Lucie. And the Corps and South Florida Water Management District are expanding storage areas to hold and filter polluted lake spill water before moving it in any direction.
But manatees and dolphins keep dying, and nobody knows how to save them. Dolphins, in particular, are harbingers of the overall health of our oceans. For that reason alone, federal and state officials should be alarmed enough to stem these killing seasons as quickly as possible.