The grounds · 180 ft · banks, ledges and wrecks

Black Grouper

Mycteroperca bonaci. Prime water reaches Islamorada in Florida Keys right now (84°F on the bottom). Fish it 49–176 ft down — that is where 85–84°F water sits off Islamorada.

LaneThe grounds · 30 fa (180 ft)

Depth it holds49–262 ft

Prime water68–82°F (workable 68–86°F)

Holds in the column49–262 ft down (on the bottom)

Judged onseabed temperature (RTOFS at depth)

Structurerequires

The water column off Islamorada

The strip is the water itself, coloured by temperature from the surface down to the 176 ft surveyed bottom at that spot — one band per RTOFS model level. The outlined stretch is where Black Grouper's temperature band (68–86°F) and the depth it holds actually overlap. That thickness is the number that matters: it is how much water you can work, not just whether the spot is warm enough somewhere. One model cycle, not a weekly archive — this holds still while the surface map scrubs.

In 3D

Drag to rotate, pinch or scroll to zoom. 3D model traced from a U.S. Food and Drug Administration, Public domain (Flickr license 8: United States Government Work) reference — source.

How it's fished

Big live bait pulled hard off the ledge — give them line and they are back in the rock.

Region by region — right now

Region	Season	Prime water	Temp	Fish it at	Months
Florida Keys	in season	reaches Islamorada	84°F	49–176 ft	J F M A M J J A S O N D
Southeast Atlantic	in season	reaches Cape Hatteras	78°F	49–179 ft	J F M A M J J A
Gulf of Mexico	in season	reaches Tampa	82°F	49–181 ft	J F M A M J J A S

"Fish it at" is where this species' temperature band and its holding depth overlap in the water column, from the RTOFS profile (13 levels, 0–300 m) — the depth to actually put a bait, not just the place. "Prime water" is the furthest sampled station on the 30-fathom lane whose seabed temperature sits inside this species' band. It is water, not a sighting report.

Charted grounds on the 30-fathom lane

Flower Garden Banks