Fishonomics/Gag Grouper
Florida Keys field guide

Gag Grouper.

Mycteroperca microlepis

Cool-water grouper. Mid-shelf structure, winter peaks.

Behavior

How they feed in the Keys

Gags are the cool-water cousin to black grouper, more abundant on Florida's Gulf side and along the Atlantic shelf. In the Keys they hold on mid-shelf wrecks and ledges 60–250 feet, often deeper in summer and migrating shallower into winter. Average 8–15 lbs with trophies pushing 30+. Less common than blacks in the Keys proper but a regular catch on Gulf-side trips out of Marathon and Key West.

Water temp

62–74°F

Active 56–78°F · Cold-water aggressive

Tide

Strong current, similar to black grouper.

Current

1.5–3 knots over deep structure. Critical for feeding.

Weather

Cold-front following days are excellent — gags are cold-water hunters.

Pressure

Falling pressure intensifies the bite.

Time of day

Dawn and last light strongest.

Moon phase

Spawning Jan–Apr at offshore aggregations. Federal Atlantic gag harvest is closed Jan 1 – Apr 30 for the spawn.

Tidal coefficient

70+ for productive deep-edge feeds.

Migration timing

Gags shift shallower in fall (October–December) as water cools, then back deep for spring spawn. Fall is the year's best window for shallower-water gag fishing.

Seasonality

12-month outlook

Peak · Sep, Oct, Nov, DecSpawn · Jan, Feb, Mar
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
PeakGoodOKSlowPoorSpawn window
Bait

What they eat, what catches them

Top 3 baits
1

Live pinfish

5–8" pinfish hooked through the back. The standard.

2

Live blue runner

Bigger fish prefer larger live baits.

3

Cut bonito chunks

Strong scent for the deep ledges.

Alternates
  • Vertical jigs· 200–300 g for deep-ledge jigging.
  • Diving plugs (trolling)· Stretch series for the shallower fall fish.
When to use what
  • Deep-ledge live bait

    Live pinfish on 8/0 circle, 100 lb fluoro, 12-oz lead. Drop and reel up 2 cranks.

Gear

How top captains rig it

Line

Spin: 65–80 lb braid. Conventional: 50 lb class.

Reel

Spin: 8000+. Conventional: 30W–50W.

Rod

Heavy stand-up class.

Leader

100 lb fluorocarbon.

Setups by situation
  • Deep-ledge

    7' heavy spin + 80 lb braid + 100 lb fluoro + 8/0 circle + live bait + 12-oz lead.

Regulations

Recreational rules

Size limit

24" total length (Atlantic).

Bag limit

2 per harvester per day in Atlantic; counts in 3-fish grouper aggregate.

Season

Atlantic: closed Jan 1 – Apr 30. Open May 1 – Dec 31.

Prohibited methods

Powerheads prohibited in state waters.

Note · Gulf state-water rules differ. Federal closures occasionally extend.

Recreational rules · FWCVerify current rules at FWC →
Bite-score factors

What actually moves the bite

Each factor is rated by how much it shifts the bite for this fish in the Keys. Calibrated against the Bite Score weights — see the Bite Score reference for what each factor measures.

Not ImportantImportant
Current Strength
90
Water Temp
90
Dawn / Dusk
85
Incoming Tide
80
Outgoing Tide
80
Barometer
70
Moon Phase
70
Wave Height
60
Wind
55
Wind vs Sea
10
Slack Tide
5
For sport fishing reference only · Not for navigationField guide · Fishonomics