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Red alert: Hurricane Ian and red tide add to challenges for redfish

Redfish in the water
Carlton Ward
This past fall, Hurricane Ian and red tide hit West Central Florida at a critical redfish spawning time, delivering a one-two punch to a fish that is back in the conservation spotlight.

Redfish are big, brawny fighters and key contributors to Florida’s $13.8 billion recreational fishing industry. But redfish have a weak spot: They faithfully return to the same waters each year to spawn. This past fall, Hurricane Ian and red tide hit West Central Florida at a critical spawning time, delivering a one-two punch to a fish that is back in the conservation spotlight.

This story was funded by the Schooner Foundation as well as readers like you.

In 2012, Sue Lowerre-Barbieri watched as thousands of spawning redfish merged into a resplendent, flashing mass in the teal waters just outside Tampa Bay.

“You could see literally a wall of gold that would come up to the surface,” said Lowerre-Barbieri, a University of Florida research professor of fisheries ecology. “They would just be wildly feeding on everything. Sometimes they come under the boat. It’s probably the most dramatic thing I’ve seen on the water.”

Also known as red drum, redfish are hardy and thrive in a variety of habitats and conditions. Redfish are big, brawny fighters and key contributors to Florida’s $13.8 billion recreational fishing industry, the most lucrative in the nation. 77% of Florida anglers target the species, according to a survey from the Florida Fish and Wildlife Conservation Commission.

But redfish have a weak spot: They faithfully return to the same waters each fall to spawn. If disaster strikes during spawning season, whether from a hurricane or a pollutant-fueled red tide, a year’s class of fish can vanish. In the 1980s, the predictability of when and where redfish spawn brought them to the brink of being fished out.

Tampa Bay and Charlotte Harbor are crucial spawning sites where adults typically gather offshore from mid-August to mid-November in aggregations as high as 10,000 fish.

Until the past few years, Capt. Brett Norris said he could count on schools of 50 to 400 large redfish appearing at Fort De Soto every October during spawning season. In 2022, he saw two to three small schools that dissipated after a few days, rather than staying for weeks. Video courtesy of Capt. Jordan Todd

This past fall, fishing guides anticipated the return of these large, breeder redfish. But spawning schools were scarce, small, and dispersed after a few days, truncating what is usually several weeks of prime fishing.

“We have a major, major issue in Tampa Bay right now,” said Capt. Brett Norris, a charter fishing guide in Pinellas County. “When it comes to snook and redfish, you can drive around for miles and see 10 fish in an area where you used to see 2,000 fish. It’s a pretty drastic change.”

Tampa-area redfish were hard-hit by red tide in 2018 and 2021, which together left a trail of at least 3,615 tons of dead sea life in Pinellas County alone. These massive fish kills caused FWC to instate temporary bans on keeping redfish along affected parts of the Gulf Coast, the last of which was lifted in September 2022.

Nobody was seeing them, including the bait fishermen we work with.
Sue Lowerre-Barbieri, UF professor of fisheries ecology

Then came Hurricane Ian. It hit Cayo Costa at the edge of Charlotte Harbor on Sept. 28 as a Category 4 storm and the fourth-strongest storm on record in Florida.

Its deluge of fresh water, nearly 16 inches in some places, could endanger the survival of 2022’s redfish eggs, which rely on saltwater currents to carry them into the rivers that serve as their nursery habitats. If water salinity is too low, the eggs will sink and die, Lowerre-Barbieri said.

Six days after Ian’s arrival, surface salinity in parts of Sarasota Bay and Lemon Bay, both up the coast from Charlotte Harbor, dropped by more than two-thirds, as a thick band of fresh water rode atop saltwater. Lowerre-Barbieri said redfish eggs could survive these conditions if they floated in the saltwater underneath Ian’s floodwaters and if the outgoing fresh water did not thwart the currents needed to get them to their nursery habitats.

Map shows aerials before and after Hurricane Ian
Sarasota Bay Estuary Program
The large pulse of stormwater from Hurricane Ian funneled bacteria, excess nutrients, and pollutants into coastal waterways. After the storm, Blackburn Bay was dark with tannins, compounds from decomposing plant material.

“This could seriously impact reproductive success,” said Lowerre-Barbieri, who leads the Movement Ecology and Reproductive Resilience laboratory, a collaborative effort between UF and FWC’s Fish and Wildlife Research Institute in St. Petersburg.

Lowerre-Barbieri’s team tracks spawning redfish along the Gulf Coast from spotter planes and boats. They also collect genetic data from adult fish and insert acoustic tags before releasing them. Tagged fish are detectable when they swim past a receiver, hundreds of which are anchored across the Gulf of Mexico. These hits help create a picture of how redfish move and contribute to estimates of their abundance.

Scientists on a boat examining redish
Scientists with the Movement Ecology and Reproductive Resilience lab (MERR) have been tracking spawning redfish from boats and spotter planes since 2012. They insert acoustic tags into select fish to better understand where redfish go and to estimate population numbers.

As expected, the team recorded the arrival of migrating redfish in Charlotte Harbor at the end of August, but the fish were late to Tampa Bay, as were the bait they feed on. Her team identified only one small group of redfish off Tampa Bay in early September, when they would have normally seen several large aggregations.

“Nobody was seeing them, including the bait fishermen we work with,” Lowerre-Barbieri said.

A few days after Hurricane Ian passed, Lowerre-Barbieri’s team saw one small group of spawning redfish off Redington Beach in Pinellas County.

While these sightings provide only a rough indicator of redfish abundance, the scarcity of spawning redfish seen after Ian seemed to parallel what the team observed during the severe red tide of 2018, Lowerre-Barbieri said.

The team was able to retrieve data from one receiver at a redfish hotspot off Tampa Bay in early January. Preliminary data from the device suggests the waters were unusually quiet after Ian.

Sue Lowerre-Barbieri, left, inspects an adult redfish while Sarah Walters Burnsed, an FWC marine fisheries biologist, records data
Carlton Ward
Sue Lowerre-Barbieri, left, inspects an adult redfish while Sarah Walters Burnsed, an FWC marine fisheries biologist, records data.

“Typically October is the peak spawning season and when we detect the most fish,” Lowerre-Barbieri said. “We never detected more than two fish after Sept. 27 [via the receiver], suggesting a shift in habitat use due to Ian floodwaters.”

‘The fish just don’t want to be here’

Charter fishing guide Capt. Neill Holland was looking forward to pursuing the schools of 26- to 36-inch redfish that typically convene around Weeden Island and Conception Key in upper Tampa Bay in October. But concentrations of fish were paltry, he said.

“Around Halloween is when we should have our big congregations of offshore redfish, like the gigantic breeder fish,” he said. “They did not show up in the kinds of numbers that we’ve seen going back to 2020. We had a couple of schools show up, but it was for a limited time, just a few days.”

Capt. Norris has seen similarly dismal numbers around Tampa Bay’s Tarpon Key.

“That area used to hold 400 or 500 fish easily this time of year, easily in October, and now it’s holding 30 fish, maybe 40 fish, in the whole area,” he said. “It’s pretty desolate. I think we’re going down a bad road.”

Norris pointed to water quality issues and specifically the 2021 red tide, which was supercharged by the release of 186 tons of nitrogen from the Piney Point fertilizer plant in Manatee County. He has also noticed the proliferation of a new moss-like algae coating seagrass.

“The fish just don’t want to be here,” he said.

Anna Maria Island-based guide Capt. Justin Moore said that following Ian, some redfish left or were pushed out by fresh water from Tampa Bay and Sarasota Bay and began sheltering on offshore reefs: “Anywhere where there was deep water and structure was loaded up with redfish.”

Man smiling and holding a redfish
Capt. Neill Holland
On Oct. 29, 2020, Capt. Neill Holland reeled in a famous Tampa-area redfish known as “The Mayor.” Most redfish have one black spot on the upper part of the tail. The Mayor’s distinctive patterning makes the fish easily recognizable among anglers. Holland memorialized the moment before returning The Mayor to the water.

Now, in areas where he formerly caught adults, Moore is hooking young redfish in the 15- to 18-inch size range.

“All the guides I know are talking about, man, it’s great to see all these little redfish,” Moore said. “I’ve just never seen this many.”

His concern, however, is that these young redfish could also become trapped and killed by red tide.

In late October, high levels of red tide appeared off Venice Inlet, south of Sarasota Bay. Ian-triggered wastewater releases and stormwater runoff are feeding the bloom, which has resulted in hundreds of recent fish kills. Redfish have been identified in at least eight red-tide kills since November, according to FWC’s Fish Kill Database.

Back in the red?

U.S. anglers spend $1.9 billion annually in the pursuit of redfish — the highest amount for any single saltwater species, according to a 2021 report from the American Sportfishing Association. This rises to $4.8 billion when factoring in the economic contributions of related businesses, such as tackle shops, marinas, fishing charter providers, and gas stations.

Today, the species is considered a conservation success story. In the 1980s, the popularization of blackened redfish, a dish invented by New Orleans chef Paul Prudhomme, triggered a fishing frenzy. Commercial fishers used the predictability of the species’ breeding waters and deployed purse seine nets, which work like giant pouches, to capture thousands of spawning redfish at a time. Commercial redfish catch in the Gulf of Mexico in 1980, the year before Prudhomme debuted blackened redfish, totaled 1.6 million pounds. By 1985, annual catch had soared to 6.3 million pounds. Redfish numbers plummeted, prompting FWC to enact several emergency closures of the fishery to prevent its collapse.

Commercial fishing for redfish is still prohibited, with the majority of redfish sold at restaurants and supermarkets sourced from Texas fish farms. In most Florida waters, recreational anglers can keep only one young redfish, sized 18 to 27 inches, safeguarding reproductively mature adults.

 A volunteer holds a hatchery-raised redfish in a container
CCA Florida
A volunteer holds a hatchery-raised redfish, part of the Coastal Conservation Association Florida’s restocking initiative in partnership with the Duke Energy Mariculture Center. CCA Florida has previously released 34,000 redfish on the Gulf Coast.

New FWC regulations beginning last September further tightened catch limits and prohibited keeping redfish from the Atlantic Coast’s Indian River Lagoon, where the species has suffered from pollutant-fueled algae blooms and dwindling seagrass habitat.

77% of Tampa Bay fishing guides rated their 2022 redfish fishing experiences as fair, poor, or very poor, according to an FWC survey. 31% of them said water quality was the top threat to the fishery. The Coastal Conservation Association Florida regularly restocks redfish in depleted areas, in partnership with the Duke Energy Mariculture Center, and is considering releases in the Tampa Bay area when its water quality improves, said Brian Gorski, CCA’s executive director.

“We’re obviously not going to release fish in those waters,” he said, citing contaminants from Hurricane Ian, red tide, and sunken boats and other debris.

For Gorski, the future of redfish looks “pretty grim” due to these statewide problems: poor water quality, habitat loss, and increasing numbers of new anglers on the water.

“Until we can get the state and the municipalities to make a commitment to make the water quality better, we’re in for a long haul,” he said.

Optimistically, Lowerre-Barbieri pointed out that a bad year for redfish is often followed by a good one. She thought 2019’s spawning aggregations would be small after 2018’s brutal red tide. Instead, her team recorded the highest number of redfish yet, likely due to new fish moving into the area.

 MERR scientists prepare to tag an adult redfish
Carlton Ward
MERR scientists prepare to tag an adult redfish. “It will be fascinating to download our receivers from off Charlotte Harbor, assuming they are still there, and Tampa Bay,” Lowerre-Barbieri said. “We have been tracking reds since 2012, so we will be able to see how the disturbances of 2018, 2021, and Ian in 2022 impacted space use.”

Still, estimating the abundance of fish is “harder than rocket science,” she said. “Ecosystems are just so complex.”

What worries her more is the misconception that ecosystems can’t be pushed past a point of no return — that they can always be saved.

“A lot of people tend to think that the world will always provide, the ocean will always provide. And, of course, it’s hard to imagine it won’t. But the Indian River Lagoon is a great example of, no, you can push it past that point.”

Natalie van Hoose is a Florida-based freelance science writer who covers water, wildlife, and sustainability. Her work has appeared in Fast Company, Florida Sportsman magazine, WEDU PBS, Cool Green Science, Creative Nonfiction magazine, and other outlets. She grew up in Cocoa Beach.

This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative formed to cover the impacts of climate change in the state.