Warm water puts strain on marine systems: Fish deaths reported in Matlacha
Man loses sailboat he lives on when it crashes into Matlacha Bridge
Christian Monzon of Homosassa was trying to help a friend when the winds of Hurricane Eta pulled the sailboat he was living on under the Matlacha Bridge.
Kaitlin Greenockle, [email protected]
There is a fish kill in Matlacha Pass and some water experts believe it is due to a lack of oxygen in the water.
The assumption is that the heat causes the oxygen content in the water to drop and many fish species to suffocate.
“I think it’s related to warming and the relatively hot water,” said John Cassani, Calusa Waterkeeper Emeritus. “When the temperature rises to that elevation, microbial activity increases. They need oxygen and compete with fish and shellfish for oxygen.”
Cassani said the warm water is one reason why fish kills occasionally occur in Southwest Florida during the summer.
The waters of southwest Florida are warming to just over 90 degrees this year, a few degrees warmer than average. While not record-breaking, the high water temperatures are still having an impact on marine ecology.
Aerial photographs taken by local pilot and Calusa Waterkeeper volunteer Ralph Arwood show the brown-colored water in the passage with hundreds of dead fish floating in it.
Expert: TS Debby at least partly to blame
Jim Beever is a retired biologist and climate planner and he said the Matlacha event likely started with Tropical Storm Debby.
More: A perplexing mystery: Why are fish still dying due to elevated toxin levels in the Florida Keys?
“With Debby, all the water flowed past the water control structures and into Matlacha Pass, and there’s going to be a lot of nutrients and pollution in that area,” Beever said. “That probably contributed to the event. It’s an anoxic event of warm water and algae.”
Beever said the algae blooming due to nutrient and pollutant loads from Tropical Storm Debby suck oxygen at night, making the problem worse.
“Warmer water can’t hold as much dissolved oxygen, and in places like Matlacha, where algae grow on the surface, those plants are also using up oxygen,” Beever said. “At night, instead of adding oxygen to the water, the plants are using up the oxygen that’s in the water. And fish in that area that can’t leave because they’re not mobile enough end up suffocating.”
Beever said it’s possible that dissolved oxygen in Matlacha Pass wouldn’t be a problem if it weren’t for the stormwater runoff from Cape Coral.
Pollution leads to fish deaths
“It’s quite possible that if there were no pollution, we wouldn’t have as many fish kills as we did with warming,” Beever said. “Lack of oxygen is the cause of the deaths, but the reason for the lack of oxygen is the interaction of several factors.”
More: DOH issues blue-green algae warning for Caloosahatchee River. Where else are there algal blooms?
James Douglass, a professor at Florida Gulf Coast University, wrote on Facebook that residents should get involved to learn more about and advocate for Florida’s sick waters.
“Southwest Florida has chronic water quality problems resulting from decades of sprawling growth, crippled regulations and underinvestment in green infrastructure,” Douglass wrote in a Facebook post that featured Arwood’s photos.