Pollution's killed the seagrass manatees feed on. Can lettuce save the day?

Excerpts from New York Times article by Patricia Mazzei

It was an extraordinary experiment in dire times: humans dumping pallets of leafy greens to feed Florida’s beloved manatees in the warm waters of the Indian River Lagoon, where decades of pollution have destroyed their delicate seagrass diet.

Eventually, a pair of bold manatees approached. With their prehensile lips — they are distantly related to elephants — they grabbed the lettuce and nibbled. More followed. On the coldest days, hundreds came, and over the three-month feeding period, the hungry mammals ate every scrap of the 202,000 pounds of lettuce hurled from above.

Floridians cherish manatees, rotund and gentle giants that have long captured the human imagination, but people have failed to care for the animals’ environment, putting the species’ survival at risk. Now, as manatees are disappearing in large numbers, humans are trying crisis rescue measures in desperate attempts to keep them alive.

With the state’s sprawling development that has damaged the natural plumbing of Lake Okeechobee and the Everglades, there is a threat to the drinking water supply which has also left the state gravely vulnerable to climate change.

Manatees had been something of a success story, their status upgraded to threatened from endangered in 2017 after years of educating boaters to avoid deadly strikes. Starvation has once again put them in peril.

Along Florida’s Atlantic coast, the die-off began last year, after the Indian River Lagoon, a 156-mile estuary that had been a seasonal manatee refuge, turned into a barren underwater desert. Decades of waste from leaky septic tanks and fertilizer runoff from farms and development fueled algal blooms that blocked the sunlight and choked the seagrass that manatees used to eat.

The feeding experiment, conceived and executed by federal and state wildlife officials and fueled by $116,000 in public donations, was a gamble. Between Jan. 1 and April 1, the number of confirmed deaths fell to 479, down from 612 in 2021. In 2020, that figure was 205.

In all of last year, 1,100 Florida manatees died, a record. About 7,500 are thought to remain in the wild.

This year’s dip in deaths does not necessarily mean that starvation has eased and feeding has helped. Scientists will spend the summer reviewing environmental conditions, necropsy results and other data to make a more complete assessment. 

Floridians share a special affection for manatees. Threatened with extinction, manatees are “adopted” by people who make charitable donations to support their protection. “Save the Manatee” is one of the state’s most popular specialty license plates. Homes display manatee mailboxes.

But neither fondness nor economic interest has stopped humans from posing a deadly threat — first from boat strikes, which have long caused manatee deaths, and now from pollution, which has destroyed much of their food supply.

Everyone agrees on the ideal long-term solution: restoring the lagoon habitat through a variety of efforts, from growing and planting new seagrass beds to improving stormwater drainage to moving properties on septic tanks to sewer systems. But all of those projects are expensive and will take years. To critics, the feeding program was woefully insufficient — too late and far too limited, both in the amount and type of food provided to the animals.

The outlook is not uniformly bleak. Some lucky manatees spent the winter 70 miles northwest of the Indian River Lagoon. The animals had swum to the gem-toned Blue Spring, about halfway between Orlando and Daytona Beach, where they could escape the cold water and be near the abundant foliage of the St. Johns River.

Wayne Hartley, a jolly 78-year-old manatee specialist with the Save the Manatee Club, set out to count the animals, as he has done since 1980. When he started, 36 manatees wintered at the spring. This year, the season-high was 871, a record — and a testament to how some preservation efforts have worked.

Mr. Hartley hopes something else is going on, too: Perhaps manatees that would normally seek refuge in the Indian River Lagoon are trying to adapt to seagrass loss by traveling elsewhere.

In the Indian River Lagoon, the turbid brown waters are much less hospitable. The lagoon’s arid bottom, now made up of little more than sand and horseshoe crabs, is a sobering sight.

“I remember when the water was crystal clear, and you could see pastures of seagrass,” said Katrina Shadix, an environmental activist who fished in the lagoon decades ago. “This used to be the most amazing, beautiful estuary. The ecosystem has collapsed.”