Fishing and diving off Pinellas and Pasco counties in Florida could be disrupted for more than a year because huge numbers of fish are dying in an oxygen-starved zone of the Gulf of Mexico.
Data released Tuesday show oxygen in the gulf has dropped to severely low levels in an area that begins about 10 miles off the coast of mid Pinellas County and extends north to Pasco County.
Scientists say it appears the phenomenon was brought on by an especially long-lived episode of Red Tide, which has been blooming in the gulf since January.
Wayne Genthner, captain of Wolfmouth Charters and an avid scuba diver, calls it “one of the greatest environmental disasters in the history of Florida.”
Most scientists won’t go that far. But all agree it’s a serious problem that hurts diving, angling and tourism, along with the environment itself.
The newest scientific evidence, from the state Fish and Wildlife Research Institute, confirms what divers and fisherman have been saying for weeks: The oxygen-depleted areas have turned into fish graveyards.
Boaters have found goliath grouper bobbing dead on the gulf’s surface and sea turtles too weakened to dive. Divers have searched the sea floor, only to find dead sponges and coral and shells of crabs with no living animal inside.
“It’s been devastating … there’s just massive fish kills,” said Dave Mistretta, captain of the Jaws Too fishing boat in Indian Rocks Beach.
Cynthia Heil, senior research scientist at the institute, said the effect on marine life on the sea floor is the worst since a massive Red Tide bloom in 1971.
Long-time beachgoers along the Suncoast are familiar with Red Tide, a toxic growth of algae that can kill fish. Outbreaks also can cause respiratory problems in humans.
But this episode is much more severe, Heil said, and unusual because it came so early in the season. Red Tide is most common in the fall. This outbreak began in January and has lasted through summer.
This summer bloom is occurring when the gulf has a strong “thermocline,” a layer of water where the temperature changes quickly.
The thermocline, which separates the warmer surface water from the cooler bottom water, traps the toxic bloom near the bottom of the gulf, worsening its effects there, Heil said.
When the algae’s toxins kill fish, bacteria breaking down the dead matter rob the water of oxygen.
The strong thermocline also prevents oxygen produced near the surface from descending. Both the depleted oxygen levels and the Red Tide can kill fish. Many anglers and divers have seen the evidence firsthand.
Genthner, the scuba diver, said he saw fish die before his eyes, dropping to the bottom of the ocean like dead leaves. Big and ancient conch shells that Genthner had watched for years have vanished.
“The worst part is what you feel when you see what used to be a cornucopia of beauty and grace, beautiful tropical fish and coral and big strong grouper, and all of that is eliminated,” he said.
“It draws the life out of you. That stuff really hurts.”
He said he used to do about $3,000 a week in charter business. Some weeks this summer he only earned $300, he said.
Herman Maddox, captain of the Sea Fox dive boat in Dunedin, said he sailed out through Hurricane Pass on Sunday and saw dead fish bobbing about 7 miles off shore. He stopped 10 miles out and dove, but the water was “a milky greenish color with about 3 feet of visibility down to about 25.” At 40 feet below, visibility was only 1 foot.
Later, they sailed 12 to 14 miles off shore and dove again. “At 38 feet it went black,” he said.
He said he also came upon a sea turtle Sunday, but it was too weak to dive away, as they normally do when a boat approaches. He said he took it to the Clearwater Marine Aquarium.