Sweet & Salty

Delta Estuaries Dish Out A Mixed Bag

John Felsher April 9, 2012

In many coastal deltas, fresh river water mixes with ocean brine, forming a rich primordial stew where life thrives in one of the most fertile and diverse habitats in North America. Anglers fishing these glory holes may land a dozen or more diverse species on any given day.

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As water from two worlds collide in the delta, many aquatic and marine species can co-exist. Some freshwater species tolerate some salty water, while some salty species venture into freshwater. On any given day, Florida anglers may catch aquatic largemouth bass, bluegills, redear sunfish, warmouth, several catfish species, crappie and salty species including speckled trout, snook, flounder, redfish, striped bass, sheepshead, gafftopsail catfish and black drum. Some species, such as alligator gar, tarpon, bull sharks and mullet easily slip between both worlds at will.

As long as salinity changes gradually, most freshwater fish can adjust. This phenomenon is one of the most appealing and unique aspects of coastal fishing.

“Anywhere that a river flows toward the coast, freshwater mixes with saltwater,” said Allen Martin, a Florida Fish & Wildlife Conservation Commission biologist in Lake City. “In this mixing zone, the ranges of various marine and freshwater species overlap. As long as salinity changes gradually, most freshwater fish can adjust. This phenomenon is one of the most appealing and unique aspects of coastal fishing. People can catch so many different varieties of fish in the same areas.”

Like salmon, striped bass and American shad spend most of their lives at sea, but enter freshwater rivers to spawn. In late winter, shad make a run up the St. Johns River, possibly traveling as far as 200 miles from the Atlantic. Gulf striped bass once flourished in many of Florida’s river systems and they still reproduce naturally in the Apalachicola River. Stripers also occur in the St. Mary, St. Johns, the lower Ochlockonee, Blackwater, Yellow, Escambia and Choctawhatchee River. Many states release stripers into landlocked reservoirs such as Lake Seminole and Lake Talquin.

Where freshwater mixes with brine in delta estuaries, game fish from different habitats often prey upon the same forage. They gorge on a rich smorgasbord of freshwater grass shrimp, shad, shiners, crawfish, minnows and sunfish, or munch on marine morsels like crab, shrimp, menhaden, mullet, pinfish, croaker or a thousand other creatures. Sometimes, freshwater species attack prey from one direction while marine species hit them from another direction. Beneath the mayhem, flounder and catfish devour anything that drops to the bottom. Under the right conditions, anglers may catch a number of aquatic and marine game fish at the same time in the same place on the same lure.

“Back in some creeks in Flagler County, we might catch a snook on the first cast, a redfish on the second cast, a black bass on the third and a tarpon on the fourth cast,” said Captain Chris Herrera of Palm Coast Fishing Guide Service (palmcoastfishing.com). “On some days on the Timoka River, I’ve caught trout, redfish, snook, tarpon, alligator gar, sheepshead and black bass within 100 yards of each other.”

Largemouth bass and redfish probably account for the most divergent catches in delta estuaries. Bass can tolerate salinity. Redfish can live in pure freshwater, although they cannot breed there. In fact, some states stock redfish in landlocked reservoirs where they do quite well. On the St. Johns River, bass anglers sometimes catch redfish as far inland as Lake George, while redfish anglers sometimes catch largemouth bass in the delta near Jacksonville. Bass and redfish frequently feed in close proximity to each other and may attack the same forage at the same time. Any lure a bass will hit, a redfish will hit and vice versa.

“Fishing for redfish is a lot like fishing for bass,” said Stephen Browning, a Bassmaster Classic veteran who fishes professional redfish tournaments. “I’ve caught redfish on conventional spinnerbaits and many other bass lures.”

What one catches in a particular spot on any given day largely depends upon water flow. In river deltas, conditions fluctuate daily and sometimes hourly as freshwater flows battle salty tides for dominance in coastal estuaries. The incredibly blurred demarcation between the two types of water blends and moves constantly. During an incoming tide, bass may retreat to sweeter water upstream or move further back into flooded shoreline vegetation. During a falling tide, bass may drop into the main channels or move closer to the delta. A hard rain upstream may flood a river, pushing marine species farther downstream. During a drought, the opposite occurs as saltwater moves farther inland. Winds can also blow water around, influencing tides and where fish concentrate. On any given day, a good bass spot in the morning may hold speckled trout in the afternoon.

“It’s very common in coastal Florida to catch multiple species in a small area,” said Bob Wattendorf, a FWC biologist in Tallahassee. “Bass can tolerate up to about 10 parts-per-thousand of salinity with no problem. Seawater is about 35 ppt. When the salinity of a fish’s blood is comparable to the salinity of the water, that’s actually one of the least stressful conditions for a freshwater fish.”

Fish don’t necessarily disappear just because the water changes. Heavier, denser saltwater sinks, while a layer of freshwater may “float.” Sometimes a river delta may look brown, but two feet below the surface the trolling motor kicks up clear water. In many coastal deltas, a slug of salty water may stay near the bottom and extend miles inland, despite river currents. Spending most of their lives flat on the bottom, flounder frequently follow this narrow slug of briny water quite far up coastal rivers.

Under those conditions, saltwater species may go deep to find water they like while freshwater species head to the surface. Anglers looking for redfish, snook or trout may drag bottom-bouncing baits while bass anglers may stick with topwaters or buzzbaits. Who knows what may jump on a spinnerbait or crankbait.

“In the Suwannee River delta, I’ve personally caught redfish, trout, bass, snook, black drum, bluegill, stumpknockers, sheepshead, flounder, redbelly sunfish and other species in a short time,” Martin said. “On some days, under the right conditions, we’ve caught 12 to 13 species. We’ve literally picked up snook and bass right next to each.”

“In the Apalachicola River delta, it’s very common to catch different species in the same area with the same lures,” said Captain Rex Phipps, a guide in Apalachicola (captrexphipps.com). “Once, I caught a 3-pound largemouth and a 2-pound speckled trout on the same cast with a double jig rig. I’ve probably caught 10 to 12 species in the same day. When the river floods, it flushes freshwater fish downriver and we catch bass out on the flats when fishing for redfish and trout.”

Many coastal Florida streams also provide good fishing for multiple species. These include the Choctawhatchee, Crystal, Escambia, Homosassa, Steinhatchee, Withlacoochee and any other Panhandle river. In some Everglades canals, anglers catch fresh and salty species. Any stream that flows into saltwater can provide opportunities to catch a mixed bag.

“All of the rivers that feed into the Gulf of Mexico hold bass,” said Captain Tommy Thompson, a saltwater guide who fishes the Big Bend area (flanaturecoast.com/capttommy). “We’ve also caught redfish in the headwaters of the Crystal River.”

In Florida, the fish species one targets determines which license an angler needs. Anglers casting for bass need a freshwater license, even if they fish at the edge of Apalachicola Bay. On the other hand, anglers chasing American shad up the St. Johns River must possess a saltwater license. When there’s a possibility of both sweet and salty species, play it safe and purchase both licenses.

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