Red tide: Could it kill East Coast manatees, turtles and dolphins? | Florida red tide map

Tyler Treadway | Treasure Coast Newspapers

Show Caption Hide Caption Except for dead sea life, beaches largely empty in IRC due to red tide Dead fish continue to wash ashore on closed Indian River County beaches, such as Golden Sands Park, seen Thursday, Oct. 18, 2018, due to red tide.

The tens of thousands of dead fish picked up Wednesday on Indian River County beaches ranged from "little guys the size of your pinky finger to 5-foot-long eels," said Erik Toomsoo, president of the Vero Beach Lifeguard Association.

But no dead dolphins, turtles or manatees have been reported.

Could they be next?

More: Vero Beach red tide: Indian River County plans entire beach cleanup | Florida red tide map

More: Where is the red tide today? | Current map of east, west, Panhandle coasts

That depends on how long the red tide lingers, according to a spokeswoman for Mote Marine Laboratory & Aquarium in Sarasota.

Besides millions of pounds of fish, the Gulf Coast red tide has killed hundreds of sea turtles, dozens of manatees and dolphins and even a whale shark. And researchers reported more dead animals piling up on the sea floor.

More: Red tide causing dead zone in Gulf of Mexico

That red tide began last October, said Mote's Stephannie Kettle, "and we didn't see dead marine mammals until August. It takes a while for the toxins in those animals to accumulate."

Graphic video: Manatee decomposes during Florida's toxic algae crisis Manatee decomposes in Sanibel amid Florida's toxic algae and red tide crisis. Hundreds of dead sea animals continue to wash ashore throughout Florida.

Fish die quickly because they're literally swimming in the toxins, which flow into their gills and attack their nervous systems.

More: Red tide's long-term health effects need study, FAU scientists tell Nelson

Dolphins, sea turtles and manatees can get the toxins in two ways:

From the food they eat: Dolphins can eat fish that have accumulated toxins; loggerhead sea turtles can do the same with the crabs and other shellfish they eat; manatees and green sea turtles can eat sea grass coated with red tide cells.

From the air they breathe: Marine mammals and sea turtles come to the surface of the water to breathe, and that's where aerosolized toxins are the thickest.

Sea turtles and manatees suck in air as they rise to the surface, but dolphins "take explosive breaths" through their blowholes, Kettle said. "We think they may be blowing away some of the toxins as the breathe, but they're still taking in plenty of them."

Red Tide: How it harms the environment and kills sea life Red tide is a harmful algal bloom that can sicken or even kill local wildlife. It also causes respiratory issues in humans and other animals.

Exposure time

Scientists don't know how long marine mammals and turtles have to be exposed to red tide for it to be fatal.

"Obviously, the longer the exposure, the higher the risk," Kettle said.

Fortunately, the red tide along the Atlantic Coast is relatively small and patchy, said Malcolm McFarland, a research associate at Harbor Branch Oceanographic Institute at Fort Pierce.

Thousands of dead fish wash ashore as red tide blooms off Vero Beach Indian River County shores were covered in dead fish Oct. 17, 2018. Red tide has been detected at medium to high levels off the coast, according to the Florida Fish and Wildlife Conservation Commission. MARY HELEN MOORE/TCPALM

More: Why is red tide at Vero Beach worse than other sites?

"Sure, it's large enough that we've got high concentrations at sites several miles apart," McFarland said, "but we also have high concentrations at some spots and lower ones just a couple of miles away."

For instance, McFarland found medium levels of red tide (100,000 to 1 million cells per liter of sea water) at Indian River County's South Beach Park, but very low levels (1,000 to 10,000) were found at Round Island Beach Park, just four miles away.

Big Bloom Theory

That wasn't the case on the Gulf Coast, where the red tide bloom was 150 miles long and 10 miles wide at its peak this past summer, Kettle said.

That's as long as the Indian River Lagoon, which stretches from the Ponce Inlet in Volusia County to the Jupiter Inlet in northern Palm Beach County, and a little wider than the distance from the coastline to Florida's Turnpike along Martin and St. Lucie counties.

More: Satellite Beach tests high for red tide

And the Gulf Coast red tide "wasn't patchy like your bloom on the East Coast," she added. "It was consistently concentrated. So that was a lot of distance to swim to get out of it. With a patchy bloom, animals can swim out of dense areas."

Once critters get out of the bloom and "breathe good air and eat good food, they can recover," Kettle said.

Helpful numbers

Martin County beach conditions: 772-320-3112

St. Lucie County beach conditions: 772-462-1421

Indian River County beach conditions: 772-226-4000

Red tide health concerns: 800-222-1222 (Florida Poison Control Center)

Report fish kills: 800-6360511 (FWC)