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Is using fish killed by red tide an option for composting?

Posted at 5:18 PM, Mar 09, 2023
and last updated 2023-03-10 07:47:12-05

ESTERO, Fla. — Tons of dead fish continue to be collected along the beaches in Southwest Florida. But with fish getting sent to the landfill in Lee County, the question has been raised; is there a better way to deal with the dead red tide-poisoned fish?

Researchers at Florida Gulf Coast’s Water School are looking into methods of how to mitigate red tide and how to deal with all those dead fish. I spoke to a researcher looking to turn those fish into compost.

“You have a lot of floating dead fish, similar to what we have right now. Let’s come up with a way to do something with them outside of dumping them in a landfill,” said Adam Catasus with FGCU’s Vester Field Station.

Catasus decided to investigate composting fish a few years ago, but questioned if the red tide toxins would remain.

“It’s a pretty stable toxin out in nature and the field,” said Catasus. “The cells will burst and the toxins will come out. And if the toxins are in the water, they will eventually sink into the sediment. And it will stay there for a while.”

Catasus gathered red tide-killed fish from Mote Marine Lab and set up one barrel with added bacteria to make composting faster and with a more agricultural method as well as a separate non-altered one for control.

“Every three days you would have to go out there and stir it,” said Catasus. “You want to make sure you are allowing the bacteria to get oxygen.” And after a few weeks, Catasus said the smell was almost unbearable.

“You would have these respirators on, like the ones you see on tv shows with radioactivity like in Chernobyl,” said Catasus. “We had those, and it didn’t work.” But what worked was turning the fish into compost without harmful toxins remaining. Despite the success, Catasus never tested growing anything in the compost, but he still believes this a viable option.

“I believe it would be doable,” said Catasus. "It just takes time — just getting people on the same page. Be prepared, because these blooms come out of nowhere as we know.”

While composting the fish was successful, Catasus says there are two issues they ran into that would need to be figured out if this would be successful on a large scale — how to collect the fish and how to distribute the compost to the users.