Southern flounder in
North Carolina.

First, which flounder

The fish in NC's sounds and creeks is the southern flounder, managed by North Carolina itself. Its cousin the summer flounder (fluke) is a different, more northern species under interstate management. Plenty of writing online mixes the two up; the seasons, rules, and biology below are southern flounder, the one you're actually catching inside NC waters.

An ambush fish, head to tail

The stock assessment's own words: demersal, lie-in-wait predators that camouflage themselves on the bottom and ambush their prey. That biology tells you where to look: mud and sand-mud bottom, and especially the edges: marsh banks, channel margins, the seams where one bottom type gives way to another and bait has to cross open ground. Notably absent from the literature: any tie to seagrass or oyster the way red drum have. Different fish, different map.

What the tide actually does for flounder

One telemetry study has directly tested it, and it found no measurable difference in flounder habitat use between rising and falling tides. None, across five habitat types, day or night. What the tide does change is depth: at high water, flounder push shallower, following the flood up onto ground that was dry or skinny an hour before. Tide direction gets plenty of ink in fishing guides; the direct measurement says depth is the variable that matters. Fish where the water just arrived. That's how Pisces scores them: hour by hour through the tide's changing depth at each spot, rather than a rising-versus-falling rule the evidence doesn't support.

The year

Spring and summer: fish spread through the estuary on the soft bottom and edges described above. Fall: the migration. Mature fish stage toward inlets and move offshore to spawn, which is why late-season fishing concentrates near the mouths. Winter: juveniles overwinter far up the low-salinity ends of creeks and rivers. Cold is the real limit: field observations put their floor at roughly 2–4 °C, and hard freezes hurt them.

How Pisces forecasts them

Pisces maps every edge and drain in the water it covers at 1-meter resolution and scores flounder's hours through depth, the tide-driven variable the research supports, plus season, temperature, and bottom type. The measured accuracy behind that is on the how it works page. Compare red drum and black drum, which light up entirely different parts of the same map.

Sources

• NCDMF, 2019. Stock Assessment of Southern Flounder in the South Atlantic, 1989–2017 (SAP-SAR-2019-01).
• Furey, Dance & Rooker, 2013. Fine-scale movements and habitat use of juvenile southern flounder in an estuarine seascape. J. Fish Biology 82.
• Burke et al., 1998, via Louisiana DWF Southern Flounder FMP (2023): tidal-stream transport of juveniles in high-flow NC water.
• Williams & Deubler, 1968. Chesapeake Science 9(1) — larval occurrence temperatures in NC estuaries.