Blood cells burst when tainted water is sucked into their gills”

Golden algae’ is cause of Hanna Park fish deaths, Florida Times-Union, March 23, 2011:

Algae that can rupture blood cells in fish is being blamed for deaths of thousands of fish at a lake in Jacksonville’s Hanna Park. …
[I]t can be deadly for fish, whose blood cells burst when tainted water is sucked into their gills.
[T]he lake is a short distance from the oceanfront…
The fish deaths have some similarity to kills that happened last summer in several parts of the St. Johns. In those cases, redfish and some other species also died after blood cells ruptured, a process called hemolysis.

'Golden algae' is cause of Hanna Park fish deaths

A lake remains open to anglers despite the bloom.

By Steve Patterson

Algae that can rupture blood cells in fish is being blamed for deaths of thousands of fish at a lake in Jacksonville's Hanna Park.

Tests completed Tuesday found a single liter of water from Hanna Lake could hold 3.6 million cells of Prymnesium parvum, an organism dubbed golden algae because of the unusual discoloration it causes.

The bloom apparently started about a week and a half ago, said Dana Morton, a city biologist who examined the lake looking for other possible reasons for the fish kills.

The algae don't pose any risk to people or other mammals, said Jennifer Wolny, a scientist who studies harmful algae at the Florida Fish and Wildlife Conservation Commission.

But it can be deadly for fish, whose blood cells burst when tainted water is sucked into their gills.

Largemouth bass, crappie, catfish, bream and mullet have been killed at Hanna Lake, said Carli Segelson, a conservation commission spokeswoman.

Park employees have been cleaning up remains and left the lake open to anglers, said Ben Pennymon, a city park system spokesman.

A series of "finger ponds" around the lake haven't shown signs of the fish kill.

Golden algae live in lakes and ponds in many countries but have rarely been noticed locally. In 14 years of water testing, the St. Johns River Water Management District has never documented a golden algae bloom, agency spokeswoman Teresa Monson said.

Morton said the bloom gave parts of the lake an olive or "pea soup" appearance, cloudy but without clumps or fibers common to some algae.

The 40-acre lake is in the western part of Hanna Park, which

sits just south of Mayport Naval Station.

Although the lake is a short distance from the oceanfront, it empties into a waterway that flows west to the Intracoastal

Waterway, said Matt Gardner, a fisheries biologist for the conservation commission. He noted Intracoastal water sometimes flows upstream into the lake, making water there saltier and possibly affecting the algae, which favors brackish conditions.

Wolny said springtime is a good season for golden algae, which grows better when water is still somewhat cool. With the high levels found this week, she said, some part of the bloom might linger for a while.

The fish deaths have some similarity to kills that happened last summer in several parts of the St. Johns. In those cases, redfish and some other species also died after blood cells ruptured, a process called hemolysis.

Months of follow-up study by scientists also focused on algae blooms as a factor, but tests in those areas found different kinds of algae.

Call Steve at (904) 359-4263.