What South Slough Offers and Why It Matters

South Slough is a brackish-water system just outside Slidell that sits between the freshwater influence of the Pearl River and the full salinity of Lake Pontchartrain. The water here is neither fully fresh nor fully salt, which means the fish species change with the seasons and with how much rain has fallen recently. You'll find largemouth bass, redfish, spotted seatrout, and catfish all using the same water at different times of year, and sometimes the same day depending on tide and salinity levels.

The slough itself is shallow—most of it runs 2 to 5 feet deep—with marsh grass, cypress stands, and mud banks. The shallow water means you can wade in many spots, and the structure is dense enough that you don't need to cover huge distances to find fish. Access is straightforward from Slidell, and the water is protected from the wind that can make Lake Pontchartrain rough.

Key Takeaways

  • South Slough holds largemouth bass, redfish, spotted seatrout, and catfish, with species dominance shifting by season and recent rainfall.
  • The water averages 2 to 5 feet deep with heavy marsh grass and cypress, so shallow-draft boats or wading work better than deep-water rigs.
  • Salinity changes with tides and rain, so the same lure or technique may work one week and fail the next if conditions shift.
  • Spring and fall bring the most consistent fishing; summer heat pushes fish deeper into channels, and winter cold slows activity.
  • Launch access is available at Slidell boat ramps, and the slough is close enough for a half-day trip from town.

Seasonal Patterns and When to Fish

Spring (March through May) is the most reliable season. Bass spawn in the shallows, redfish move in from deeper water to feed on baitfish in the marsh, and seatrout follow the same baitfish. Water temperatures climb into the 60s and 70s, and fish are aggressive. Early morning and late afternoon are best, but midday can produce if you work the deepest grass edges and channel drop-offs.

Summer (June through August) is harder. Heat pushes most fish into deeper channels and the mouths of tributaries where water stays cooler. Catfish remain active and even improve as the water warms, but bass and seatrout become picky. Fish early, before 9 a.m., or wait for cloud cover. Redfish stay shallow but move to the shadiest grass and the deepest pockets within the marsh.

Fall (September through November) rivals spring. Water cools, baitfish concentrate, and all species feed heavily. Redfish and seatrout are especially active in October and early November. Bass bite well on topwater and shallow cranks as they feed before winter.

Winter (December through February) slows everything. Fish move to the deepest holes and channels. Bass fishing is possible but requires patience and slow presentations. Catfish remain the most reliable target. Many anglers shift effort to Lake Pontchartrain or the Pearl River during this period.

Lures, Rigs, and Techniques That Work

For bass, shallow-running crankbaits and topwater plugs work well in spring and fall when fish are in the grass. Soft plastics—4- to 6-inch worms and crawfish imitations—produce year-round in deeper grass edges and around cypress. Spinnerbaits are effective in stained water and around structure. Cast tight to grass edges and work slowly; the fish here are not always aggressive.

Redfish respond to live mullet, live shrimp, and cut baitfish on simple rigs: a 1/0 to 3/0 circle hook, 12-inch leader, and a small split shot or no weight at all in the shallows. Topwater plugs and shallow soft plastics also draw strikes, especially in spring and fall. Work the grass edges and channel mouths where redfish hunt for baitfish.

Spotted seatrout prefer live shrimp under a popping cork in 3 to 5 feet of water, or small soft plastics on light jig heads. They are sensitive to salinity swings; after heavy rain, they may move out temporarily, then return as salinity stabilizes. Catfish take live or cut mullet, shrimp heads, and chicken liver on basic bottom rigs. Fish the deeper holes and channel bends, especially at dawn and dusk.

Salinity Swings and How They Affect Fishing

South Slough's salinity is not constant. Heavy rain pushes freshwater down from the Pearl River and lowers salinity throughout the system. When this happens, redfish and seatrout may leave temporarily, while bass and catfish become more active. A week of dry weather and normal tides raises salinity, and the salt-water species return. This cycle repeats throughout the year and can change your best target species week to week.

Check recent rainfall before you plan a trip. If it rained hard in the past two or three days, expect lower salinity and better bass and catfish fishing. If it's been dry for a week or more, redfish and seatrout will be more reliable. Local tackle shops in Slidell can tell you the current conditions and what's biting; they track this constantly because their customers depend on it.

Wading, Boat Rigs, and Getting Around

South Slough is shallow enough to wade in many areas, especially the upper reaches and the marsh flats. Wear a good pair of wading boots—the bottom is soft mud and grass, and you can sink. A shallow-draft skiff or a poling skiff is ideal if you have a boat; 18 to 22 feet is common, with a 4- to 6-inch draft. Kayaks and canoes work well and let you move quietly through the grass.

Launch from the Slidell boat ramps—the Lakeside Marina ramp and the public ramp at Pontchartrain Park are the closest. From either ramp, South Slough is 10 to 15 minutes by boat. If you wade, park at the ramp and walk the banks or wade from the shallow flats near the launch. The water is murky, so watch for submerged logs and cypress knees.

What to Bring and What to Expect

Bring polarized sunglasses—they help you spot fish in the shallow, stained water and also protect your eyes from the sun reflecting off the water. A good headlamp or flashlight is essential if you fish early morning or late afternoon. Insect repellent is necessary, especially in summer and fall when mosquitoes and biting flies are thick. Bring more water than you think you'll need; the sun reflects hard off the water and the air is humid.

Expect to see other anglers, especially on weekends and during spring. The slough is popular with locals, and word spreads fast when fish are biting. Early morning and weekday trips are quieter. The water is murky year-round, so don't expect to sight-fish; work structure and use your senses to locate fish. Patience and repetition work better than speed.

Frequently Asked Questions

Do I need a Louisiana fishing license to fish South Slough?

Yes. Louisiana requires a fishing license for anyone 16 and older. You can purchase a license online through the Louisiana Department of Wildlife and Fisheries website, at tackle shops in Slidell, or at most big-box retailers. Licenses are available as daily, 3-day, or annual options.

What's the best time of day to fish South Slough?

Early morning (one hour before sunrise to mid-morning) and late afternoon (two hours before sunset through dusk) are most productive. Fish feed during these cooler parts of the day. Midday can work in spring and fall, but summer midday fishing is slow unless you find deep channels or heavy shade.

Can I fish South Slough in winter?

Yes, but it's slower. Fish move to the deepest holes and channels and bite less frequently. Catfish remain active and are your best bet. Bass and redfish are possible but require patience and slow presentations. Many anglers shift to other waters during winter, so you'll have the slough quieter.

What happens to the fishing after heavy rain?

Heavy rain lowers salinity and pushes redfish and seatrout out temporarily. Bass and catfish become more active. The fishing usually recovers within a week as salinity stabilizes. If you fish within two days of heavy rain, target bass and catfish instead of salt-water species.

Is South Slough safe to wade alone?

Wading is generally safe, but the bottom is soft mud and you can sink. Wear good wading boots and a life jacket. The water is murky, so watch for submerged logs and cypress knees. Wade during daylight, tell someone where you're going, and avoid wading alone if possible.