UTERTo find fishing spots on a map, look for edges: places where depth, bottom type or current changes. On satellite imagery that means color changes in the water, such as dark grass against light sand, potholes, bars and oyster lumps. On a nautical chart it means depth contours bunching into a drop-off, plus the symbols for wrecks, rocks and obstructions. Add your state's published artificial reef coordinates, then load the marks onto your chartplotter with a GPX file.
Here is how to read each kind of map, what to look for by structure, and how to move what you find onto the boat.
Step 1: Read satellite imagery for inshore water
Satellite and aerial photos show the bottom in clear, shallow water better than any chart. Zoom in on a flat or a shoreline and read the colors:
| What you see | What it usually is | Who lives there |
|---|---|---|
| Dark green or brown patches on a light flat | Seagrass | Trout, redfish, snook, pinfish and shrimp |
| Light round spots inside dark grass | Sand potholes | Redfish and trout waiting in ambush |
| Dark round spots on a light sand flat | Deeper holes | Fish dropping off the flat on the low tide |
| Light lines or crescents | Sand bars and bar edges | Fish on the down-current side |
| Grey-brown lumps along shore, often in rows | Oyster bars | Redfish, sheepshead, black drum |
| A sharp change from pale to deep blue | The drop where a flat falls into a channel | Almost everything, especially on a falling tide |
Two tips. First, imagery is a snapshot: the date matters, because bars move after storms and grass changes with the seasons. Second, the water has to be clear for any of this to show. If one image is murky, try another layer or another date.
Step 2: Read a nautical chart for depth and hard structure
A NOAA nautical chart tells you what satellite cannot: depth in water you cannot see through, and the hard structure on the bottom. NOAA's U.S. Chart No. 1 explains every symbol. These are the ones anglers use most:
- Depth contours. Lines connecting equal depths. Where they bunch together the bottom drops fast. That is your ledge, drop-off or channel edge.
- Soundings. The small depth numbers. A single shallow number in a field of deeper ones can be a hump or rock pile.
- Wrecks. Charted wreck symbols, with or without a depth over the top.
- Obstructions and rocks. "Obstn" and rock symbols often mark old structure, rubble or reef material.
- Bottom type. Abbreviations like S (sand), M (mud), Sh (shells), Co (coral) and Rk (rock). Hard bottom in a sea of sand is worth checking.
- Channels and markers. Deep, moving water running past flats. Channel edges and marker pilings hold fish.
Charts are made for navigation, not fishing. A charted wreck may be a scattered debris field, and an uncharted rock pile may be the best spot in the bay. Use the chart to decide where to look, then use your sonar to confirm it.
Step 3: What to look for, structure by structure
Ledges and drop-offs
Fish use depth changes as highways and ambush points. Inshore, look for where a flat drops into a channel. Offshore, look for contour lines that pinch together or a step of a few feet in otherwise flat bottom. In the Gulf off the Big Bend and the Panhandle, limestone ledges with a few feet of relief hold gag grouper and snapper.
Points
A point of land or a point on a grass line pushes current around it and creates an eddy on the down-current side. Fish the tip and the eddy, and fish the side the current is hitting on each tide.
Oyster bars
Bars show on satellite at low tide and on charts as shoal areas or "oys" notes. The edges and the gaps between bars channel the water. Redfish work them on the first of the incoming tide.
Reefs and wrecks
Natural reef, hard bottom and wrecks hold bait, which holds everything else. Mangrove snapper, grouper, sheepshead, amberjack and kingfish all relate to hard structure.
Fish attractors in lakes
In fresh water, many state agencies sink brush piles, cribs and stake beds and publish their coordinates. They are the freshwater version of an artificial reef and a great starting point for crappie and bass.
Step 4: Use state artificial reef data
Most coastal states run an artificial reef program and publish their sites. Florida's FWC Artificial Reef Program publishes every deployment with its coordinates, depth, relief and what was sunk: barges, reef balls, bridge rubble, ships. Other Gulf and Atlantic states publish their own lists, and many inland states publish fish attractor sites.
A few things to know when you use them:
- One site can be many records. Material is often dropped on different days a few yards apart. Fish the whole patch, not one pin.
- Relief matters. A reef with several feet of relief usually holds more fish than a low spread of rubble.
- Popular reefs get fished hard. The public numbers near an inlet see a lot of boats. The ones a bit farther out, or deeper, often hold better fish.
- Rules can apply. Some reefs sit inside special management areas. Check your state agency before you fish them; in Florida that is the FWC.
Step 5: Get your marks onto the chartplotter with GPX
GPX is the standard file format for waypoints. Almost every chartplotter and boating app can read it. The usual routine:
- Export your spots as a .gpx file.
- Copy it to the SD or microSD card your plotter uses, or open it in the Navionics app.
- On the plotter, use the import or "transfer waypoints" menu. Garmin, Lowrance, Simrad and Humminbird all support it.
- Check a couple of marks against the chart before you trust the whole file.
It works the other way too: export the marks you already have from your plotter and keep them in one place.
How Fish Scouter puts this on one map
We built Fish Scouter so you don't have to cross-check four websites and a paper chart. On one map you get:
- Satellite, NOAA chart and street layers, switchable, with depth shading and 3 ft contours from NOAA bathymetry.
- Charted wrecks, obstructions and rocks from NOAA's electronic navigational charts.
- State artificial reefs, including every FWC deployment in Florida (collapsed to one pin per site, keeping the shallowest depth and the biggest relief) and NOAA's national artificial reef layer.
- State fish attractors and boat ramps in fresh water across the country.
- Mapped habitat such as oyster bars, seagrass and hard bottom where the state publishes it.
- Predicted spots, clearly labelled. Some pins, such as ledges found in depth data or wadeable flat edges, are our predictions from NOAA elevation models. Their notes say "Predicted" or "unverified" so you know they haven't been surveyed.
Tap any spot to see the fish that use that kind of structure this month in that region, their season stage, and how the next days look for it. You can mark your own spots with a tap, and they stay private.
For GPX: every plan can import your plotter's marks. Captain and Guide plans can export your spots back out as GPX for Navionics, Garmin, Lowrance, Simrad or Humminbird, and show coordinates in degrees and decimal minutes ready to punch into a plotter by hand.
One rule we keep: Fish Scouter is not for navigation. Use official charts and your own electronics to run the boat.
Put the map in your pocket
We think Fish Scouter is the best way to turn a map into a fishing plan. It puts satellite, charts, state reefs and fish attractors in one place, and it tells you what's biting on each spot right now. Start a free trial, find your next spot, and send it to your plotter.