Scientists investigate cause of another fish kill in Biscayne Bay

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NORTH BAY VILLAGE, Fla. – More than 1,000 fish recently died in the northern Biscayne Bay basin in Miami-Dade County.

Rachel Silverstein, the executive director of Miami Waterkeeper, a nonprofit organization that advocates for a clean Biscayne Bay, moved quickly to assess the tragedy.

“There has been a trigger where we are seeing almost zero oxygen, Silverstein said adding, “The wildlife is literally suffocating in place.”

The conditions are similar to what triggered the 2020 fish kill. Scientists estimated that more than 27,000 marine species died that hot week in August.

“There’s simply too much pollution in the bay and that is leading to conditions where the sea grass starts to die off,” Silverstein said.

With up to 90% of seagrasses gone in parts of the northern basin, there is little to no oxygen produced on the bottom of the bay.

“That loss of seagrass because of the pollution is setting up conditions that make the bay really vulnerable to these fish kills,” Silverstein said.

On Wednesday afternoon at Pelican Harbor, scientists with Miami Waterkeeper and the University of Miami took water samples and gathered data to identify the source of the low oxygen event. The mouth of the Little River canal was an area of concern.

“We are anoxic. Anoxia means there’s almost no dissolved oxygen left in the water,” said Aliza Karim, a water quality research manager at Miami Waterkeeper.

Chris Langdon, a marine biologist with the University of Miami, sounded the alarm.

“It’s going to be extremely stressful for fish at this level,” Landon said. “It’s not enough oxygen for them.”

In preparation for Hurricane Ian, water management was forced to lower the levels of its canals into Biscayne Bay to mitigate potential flooding. This coupled with the recent king tides could have been the recipe for disaster.

“The large volume of polluted water that got discharged when the canals’ levees were dropped before the storm could have fed into this cycle setting up conditions for the bay to be experiencing this fish kill,” Silverstein said.

Scientists said cleaning up canals is vital to restore the health of the watershed, and until that is done, scientists fear these fish kills will continue to happen and worsen.

“It’s basically nature screaming out for help and we are doing everything we can,” said Irela Bague, Miami-Dade County’s Chief Bay Officer.

Click below to read more about the fish kill.

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