‘They’re all dead:’ Mississippi oyster farms take hit from Bonnet Carré Spillway
Hurricane Barry did not drive potentially toxic blue-green algae from Mississippi waters as hoped.
The freshwater algae is lingering from state line to state line in Mississippi’s coastal waters, Joe Spraggins, executive director of the Department of Marine Resources, told the Sun Herald on Tuesday morning.
The waters along Coast beaches remain closed to swimming during the height of the tourist season. Waters are testing positive for algae blooms at 21 state Department of Environmental Quality stations along the shoreline from Waveland to east of Pascagoula.
Two varieties of freshwater algae are blooming in the Mississippi Sound because of river flooding and the opening for an unprecedented duration of the Bonnet Carré Spillway on Lake Pontchartrain.
The Bonnet Carré, operated by the New Orleans District of the U.S. Army Corps of Engineers, releases Mississippi River water into the lake to prevent flooding in New Orleans and surrounding communities.
Mississippi officials have been urging the Corps to more carefully consider the fresh water’s impact on Mississippi’s estuarine environment.
With the recent rainfall from Barry, Spraggins said he does not expect the Corps to close the Bonnet Carré before the end of July. He said it will take a week to completely close the spillway and another 10 days or so for fresh water to stop flowing into the Sound.
Once the algae dies, he said, there is a possibility of a major fish kill as decomposition depletes oxygen in the water.
“We’re going to have issues until October,” Spraggins said.
He said the river is carrying blue-green algae “all the way from Minnesota.” The two species being found are dolichospermum and microcystis. The Environmental Protection Agency refers to both as HABs, or harmful algae blooms, because of their potential to produce toxins that can be harmful to humans, animals and aquatic ecosystems.
Toxins have been found in blooms, Spraggins said, but at very low levels. He said higher salinity after Barry has slowed the algae’s growth.
Seafood has tested safe. However, Spraggins said he does not recommend fishing “on top of an algae bloom.”
“Use your common sense,” he said.
The decision to open and close the Bonnet Carré ultimately rests with Maj. Gen. Richard Kaiser, who heads the Mississippi River Commission and also the Army Corps Mississippi Valley Division.
“The governor is talking to Gen. Kaiser regularly” Spraggins said. “I think they are taking our concerns seriously.”
Fresh water is also being blamed for high mortality rates of aquatic life, especially dolphins and sea turtles. Spraggins said the Institute of Marine Mammal Studies has documented 133 dolphin and 179 sea turtle deaths so far this year.