Indian River Lagoon mystery ailment killing dolphins, manatees, pelicans

By Craig Pittman
16 June 2013 (Tampa Bay Times) – The Indian River Lagoon on Florida’s east coast has long been known as the most diverse ecosystem in North America. Its 156 miles of water boast more than 600 species of fish and more than 300 kinds of birds. The lagoon is not just an ecological treasure. To the towns along its edge — Titusville, Cocoa, Melbourne, Vero Beach and Stuart, among others — it accounts for hundreds of millions in revenue from angling, boating, bird-watching, tourism and other waterfront activities. But these days the Indian River Lagoon has become known as a killing zone. Algae blooms wiped out more than 47,000 acres of its sea grass beds, which one scientist compared to losing an entire rainforest in one fell swoop. Then, beginning last summer, manatees began dying. As of last week, 111 manatees from Indian River Lagoon had died under mysterious circumstances. Soon pelicans and dolphins began showing up dead too — more than 300 pelicans and 46 dolphins so far. How bad is it? In the past week, a dolphin a day has turned up dead in the lagoon, said Megan Stolen, a research scientist at Hubbs-SeaWorld Research Institute. “When you lose the manatees, pelicans and dolphins, you know something is going on,” said Marty Baum of Indian Riverkeeper, a nonprofit environmental group that tries to act as a steward for the lagoon and the Indian River that flows into it.

Yet so far nobody can name the killer. Biologists have some suspicions but are baffled about any connection among the species’ problems. The diets are different: Manatees are vegetarians, while pelicans and dolphins eat fish. The symptoms are different: The manatees’ stomachs are stuffed, while the pelicans and dolphins are emaciated. Baum’s family has lived around the lagoon since the 1860s, but he can’t remember anything like this ever happening. The lagoon has had algae blooms before. None of them were like the one that hit it in 2011. Experts called the explosion of the greenish Resultor species a “superbloom” because it covered nearly 131,000 acres and lasted from early spring to late fall. Then came the “brown tide” algae bloom last summer, tinting the water a chocolate brown. The algae, Aureoumbra lagunensis, have been a recurring problem in Texas. Why it suddenly showed up in Florida is another mystery. The algae blooms shade out sunlight needed by sea grass. By the time the algae was done, the lagoon had lost more than half its sea grass, essential to nurturing fish and other marine species. Then came what Pat Rose of the Save the Manatee Club called “a cascade of events.” The mysterious manatee die-off began in the northern part of the lagoon last July, hit its peak around March and now produces another dead manatee about every two weeks, said Martine DeWit of the Florida Fish and Wildlife Conservation Commission. [more]