Numbers of Florida’s most popular sportfish are dwindling.

Spotted seatrout are resilient fish. Their populations rebound after freezes, red tides and hurricanes. But it’s becoming increasingly apparent to anglers and scientists that Florida’s seatrout are on the decline—and that diminished water quality and resultant seagrass loss are largely to blame.

Spotted seatrout (Cynoscion nebulosis), also known as speckled trout or simply “trout,” are prolific breeders, but local populations are limited by forage supply, which in turn depends on seagrasses which harbor and sustain “baby food,” the copepods, mysids and smaller shrimp, as well as the fishes and larger crustaceans adult trout feed on.

Over the past decade, hundreds of thousands of acres of seagrass have succumbed to freshwater discharges from inland, as in the case of the Caloosahatchee and St. Lucie River estuaries, or, in the case of Florida Bay, hyper salinity caused by shortages of fresh water runoff from the southern Everglades and Lake Okeechobee. Freezes have killed seagrasses as well as trout in Central Florida. But poor water quality and man-controlled freshwater distribution is likely at the root of the problem.

Less seagrass means less forage. Throw in drastic salinity swings, and spawning potential plummets, too. Too fresh, and eggs simply don’t hatch. And keep in mind that juvenile seatrout take refuge in heavy grasses, to hide from larger predators. Barren bottom provides neither food nor shelter.

A DEAFENING SILENCE

Dr. Grant Gilmore, former Harbor Branch researcher and founder of Estuarine Coastal and Ocean Science, has been “eavesdropping” on seatrout spawning parties for quite some time. Gilmore uses underwater hydrophones to find spawning seatrout—which croak—to track them and access their numbers. Gilmore visits known spawning sites in the Indian River Lagoon (IRL) between Sebastian Inlet and the St. Lucie Inlet primarily, and is troubled by what he is not hearing in places.

“The lack of spawning seatrout in the IRL in Martin County is shocking,” said Gilmore. “It’s as bad as the IRL waters of Brevard County. Longtime spawning spots from the Jensen Beach Causeway to the St. Lucie Inlet are devoid of fish. And it comes as no surprise given the fact that the seagrass die-off is worse in that stretch than from Ft. Pierce north.”

Gilmore says he now only hears the spawners from roughly the St. Lucie Power Plant north.

Gilmore points out an obvious culprit in the lower IRL—long-term low salinity (caused by large-volume fresh water discharges such as those from Lake Okeechobee to the St. Lucie and Caloosahatchee rivers) that prevents the development of seatrout eggs and larvae. The salinity in the lower St. Lucie River and connected lower IRL, for example, drops to well under the 17 to 35 parts per thousand that is most desirable.

“But such heavy freshwater runoff, wherever it occurs, can also carry a slug of herbicides, and in many coastal bays and in the IRL in particular, former grassflats are now barren. A perfect example is the Little Jim flat just inside Ft. Pierce Inlet. In wet season, it is awash with tannic, dark fresh water from nearby Taylor Creek, which drains both vast agricultural acreage in western St. Lucie County and suburban yards along the coast,” said Gilmore. “Something has changed, and what was a lush, grassy flat just a few years ago is now a desert, despite the clean tidal flow from the Inlet.”

DIMINISHING RETURNS

Veteran anglers are sounding the alarm and providing grim reports on trout.

Capt. Carl Eby, who owns a Jensen Beach aquarium store, fishes for trout from roughly Vero Beach to Stuart. “I don’t even fish the flats south of Jensen Beach Causeway anymore due to grass loss,” Eby said. “It’s not surprising given the lousy, dark fresh water that came up from the St. Lucie during the massive Okeechobee discharges three of the past five years. The trout are no longer there.”

Eby has shifted his efforts farther north, where grass is in better shape. “Just in the past few months, I am encouraged by new growth of shoal and manatee grass, and am catching lots of little trout as well as some good ones up to 24 inches.”

Eby credits the dry summer, and no discharges from Lake O for possible recovery. For now, Eby says he favors a total closure on seatrout harvest. “Just dropping the bag limit by a fish or two won’t get it done, and maybe three years of no-take recreational and commercial will,” he said. “For that matter, it’s time for Florida to grant spotted seatrout gamefish status.”

Farther north, Capt. Billy Rotne has been guiding on the famed Mosquito Lagoon and Banana River for 15 years. He is adamant about the need for a halt to harvest of seatrout as well as red drum in his area.

“Trout fishing was reasonably worthwhile until 2016, when the brown algal bloom killed most of the Lagoon’s grass and much of it in the Banana River,” said Rotne. “Initial blooms that occurred after the freeze in 2011 killed a lot of grasses started the downward spiral, and it became a nutrient pit with little sunlight reaching the bottom.”

Rotne said seatrout numbers are at a tipping point right now, and he has shifted his guiding efforts. “Over 75 percent of the skiff guides here have left the workforce,” said Rotne. “This barren bottom provides zero habitat for forage that young trout need, and there is nowhere for a juvenile trout to hide for that matter.”

TIGHTER LIMITS SOON?

After outcry from anglers statewide during public testimony and written comment in 2017, FWC has proposed creating five management zones rather than the original four, changing the recreational slot limit from 15-20 inches to 15-19, allowing only one fish over 19 inches per vessel rather than per person, prohibiting harvest by a guide during a paid trip, re-establishing the closed February harvest season in the western Panhandle zone and a November-December harvest closure in the Central East zone. Lastly, bag limits would be cut as follows:

    >Western Panhandle – from 5 to 3 fish.
    >Big Bend – from 5 to 4 fish
    >South Florida – from 4 to 3 fish
    >Central East – from 4 to 2 fish
    >Northeast – from 6 to 5 fish

Commercial daily limit reductions will be from 75 to 50 per harvester, and from 150 to 100 per harvester.

Stay tuned to floridasportsman.com and MyFWC.com for updates. FS

Florida Sportsman Magazine January 2020

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