ST. PETERSBURG — Walking along the edge of Crescent Lake this week, Mike Flanagan found something that has become a concern around this close-knit neighborhood: dead ducks.
In recent weeks, more than 25 ducks have died along the shores of the lake just north of downtown. Then on Sunday, fish started floating to the surface. Also dead.
"This is not normal," said Flanagan, president of the Crescent Lake Neighborhood Association. "Obviously our concern is, could we lose all the animals on the lake."
On Tuesday, the Florida Fish and Wildlife Conservation Commission performed a necropsy on one of the dead ducks.
The culprit: duck virus enteritis. Also known as duck plague.
This highly contagious herpes disease causes internal bleeding and severe diarrhea. It spreads in bird droppings and affects ducks, geese and swans — but not humans. Nothing can be done to stop it, though dead birds should be removed quickly to prevent further contamination.
Duck plague has been found in many countries but is believed to have first surfaced in the United States in Pekin ducks brought from the Netherlands in 1967. The first large outbreak in wild waterfowl took place in South Dakota in 1973 and killed 40 percent of the 100,000 wintering waterfowl there.
Here in Florida it has emerged only in the Tampa Bay area and mostly hits Muscovy ducks in the spring during breeding season, said Dan Wolf, a biologist for the wildlife commission in Gainesville.
The virus first turned up in Tampa in 2006. It has been documented seven more times throughout Pinellas and Hillsborough counties, according to the U.S. Geological Survey National Wildlife Health Center in Madison, Wis.
The Crescent Lake outbreak is the second in the past month. In March, 10 ducks died in a retention pond at Tyrone Boulevard and Park Street. This, too, was duck plague.
Residents of Crescent Lake first noticed four dead native mallards about four weeks ago. Since that time, all of the dead ducks have been Muscovies. These nonnative species are more susceptible to the disease than mallards or geese.
Still, concern has shifted to the family of geese at the lake.
In recent years, the lake attracted poachers who sold the geese at auction. In one case, a goose the neighborhood has dubbed "Mama" and two other geese were returned to the lake after neighbors and a community police officer tracked down the culprit.
"It's sad to lose any of them but if we lost Mama and Lenny and the whole goose family, it would be so sad after all we've gone through to save them," Flanagan said.
Mama and her family — she had babies last year — so far seem to be okay, though one baby goose died a week or so ago.
Janet Wuske, who lives on the lake and welcomes the lake's waterfowl in her yard, said a man knocked on her door and handed her the baby goose. It was limp but still alive.
"I tried to get water in its little beak with an eyedropper," she said. "But it died in my hands. I felt so bad. You think how long it takes for them to form in the mother and the mother is sitting on the nest forever."
Waterfowl have died several times at Crescent Lake over the past three decades. But those deaths were often attributed to avian botulism, a bacteria that grows in soil when low oxygen levels are present in the water. Fish kills, like the one that occurred this week at Crescent Lake, typically happen at the same time.
On Tuesday, as Flanagan walked the lake, he ran into Dave Bairam, a city environmental analyst who was taking Crescent Lake water samples. Bairam said preliminary tests showed parts of the lake had normal oxygen levels.
"But over there is kind of low," Bairam said, pointing toward the west side of the lake, near Crescent Lake Drive.
"But if it was avian botulism, the whole shoreline would be littered with (dead ducks)."
As he spoke, a mother mallard with half a dozen tiny fuzzy ducklings swam by. One hopped up on its mother's back, then hopped back into the water.
Times researcher Natalie Watson contributed to this report. Leonora LaPeter Anton can be reached at firstname.lastname@example.org or (727) 893-8640.