Florida’s Dirty-Water Reach

Changes in inshore water discharge damages offshore environments too

February 2, 2021
An aerial view of the Florida Everglades marshes and clouds.
Restoration of the Florida Everglades creates long-term issues in a variety of ways. Nature Picture Library/Alamy

Whenever you think of Everglades restoration, it’s easy to equate the well-publicized algae blooms, dirty-water discharges and seagrass die-offs with their impacts to inshore fishing, but most anglers don’t consider the overall reach of the devastation created by man-made water diversion. Beyond the obvious loss of juvenile-nursery habitat, the water-quality issues associated with Everglades restoration create long-term changes for the offshore-fishing community.

The Big Picture

It all boils down to water quality, or the lack thereof, which determines everything from the availability of bait nearshore to the recruitment of reef species such as snapper, and the movements of migratory species such as cobia, dolphin, sailfish, little tunny and king mackerel. As these species seek to avoid areas of poor water quality, or the ­subsequent red tide and other algae blooms they create, bluewater ­fishermen are forced to make longer runs, cover more swaths of water, and are often compelled to fish in tighter groups to be successful. All of that equates to higher fuel bills and more time and effort to find—and ultimately catch—what were once very patternable gamefish species.

To see the big picture, you have to look at the water-quality issue. Water that historically overflowed when Lake Okeechobee was high ran south along the land to the Everglades and into Florida Bay, where it helped maintain the natural salinity balance during times of high evaporation. Besides being the largest seagrass meadow in the world, Florida Bay is a juvenile nursery for many baitfish and reef species in the Florida Keys.


From around 1907 until today, agriculture and land-development interests worked to divert that water flow, building a massive dike around Lake Okeechobee, roadways that block water flow and canals that now divert water from the lake to the east and west coasts. Currently the Florida Everglades receives some 40 percent less water than historically flowed to the area, causing extreme salinity levels during periods of high evaporation. This extreme salinity leads to algae blooms known to the locals as yellow fog because of the color the blooms turn the water.

On the western coast of Florida, the untreated nutrient-rich runoff is associated with the increase in size and frequency of red tides in the Gulf of Mexico. Those tides can extend hundreds of miles along the coast and out into the open Gulf of Mexico. On the east coast, that same coffee-colored water diverted to the Caloosahatchee River is flowing out of Jupiter and Saint Lucie inlets, and at times might ­blanket the Atlantic between the inlets and out to 200 feet of water, or more. Because fresh water is less dense, and thus lighter than salt water, it tends to accumulate on the surface of ­saltwater bodies, allowing it to spread over a larger area. Saltwater species avoid exposure to fresh water by ­remaining deeper in the water ­column, but the ­natural reefs, corals and grasses, as well as less-mobile marine ­species, are ­susceptible to the nutrients, ­sediment and other detritus that settle to the ­bottom below the dirty water.

A digital rendering of Florida waterflows.
Historic and current flow of the Kissimmee/Okeechobee/Everglades watershed., Source: US Army Corps of Engineers, Jacksonville District

Changes in Fish Movement and Decline

Freshwater discharges on both coasts of South Florida are most common during the rainy months—May through October—but may extend all the way into December. During those periods, the Gulf and Atlantic populations of cobia, ­sailfish, and king and Spanish mackerel are migrating along the coasts. Luckily, all of these species are mobile enough to avoid the waterborne complications.


Ocean pelagics make concerted efforts to avoid the areas of poor water quality, but for the slower-moving members of the food chain such as shrimp, crabs and baitfish, as well as the natural water filterers such as oysters, seagrasses and sponges, the algae blooms are unfortunately often a death sentence. How that impacts the overall fishing is difficult to quantify given the lack of science and population estimates, but we do know the overall loss of those species has devastating effects on the inshore/nearshore species, so it’s easy to extend the correlation to nearby offshore waters as well.

Probably the most obvious changes are occurring with reef species such as permit, cobia, snapper and ­grouper, which are all showing declines in ­populations in these areas, along with seasonal-migration inconsistencies. A portion of the declines can be attributed to overfishing, but given the time frames of these declines, which coincide with the extreme algae blooms, fish kills and freshwater discharges over the past 10 years, the correlation is a little more obvious.

Read Next: Learn more about the Billfish Foundation’s fight for a sound future.


Here Come the Sharks

These issues also coincide with the major influx of bull sharks in South Florida waters—a species that is extremely freshwater-tolerant and more typical in large populations around the mouth of the Mississippi River Delta. These slow-growing, hyperaggressive sharks arrived in big numbers approximately eight years ago and have taken over the reefs in South Florida. In some areas such as off the coast of Palm Beach and Islamorada, they’re so prevalent that landing a fish of any ­species is a race to avoid shark predation.

In the past three years, sailfish have become one of the many targets of these sharks. What was once a rare occurrence is now commonplace, and it’s definitely having a trickle-down mortality impact on the overall sailfish population.

Nonprofit organization Captains For Clean Water was formed in 2016 when two inshore fishing guides from Southwest Florida became outraged by the impacts of the decline in water quality and decided to act to advance Everglades restoration.


Working in conjunction with a handful of environmental organizations, CFCW works to find impactful solutions to foster Everglades restoration and bring back the historic water flow away from the east and west coasts, and back south into the Everglades and Florida Bay.

The ideal scenario eliminates all ­freshwater flow from Lake Okeechobee into the Saint Lucie Canal, while decreasing the flow to the Caloosahatchee River to its historic levels by sending the water south through a large reservoir where it will be filtered prior to flowing into the Everglades and Florida Bay. Removing excessive nutrients from the water and providing areas deprived of their historic freshwater levels will restore the healthy nurseries and fish habitat as well as the overall vitality of the nearby offshore fisheries.

To learn more about Captains For Clean Water and join its efforts to protect Florida’s fragile waters, please visit


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