Blackfin Tuna.
Marathon and Islamorada humps. Dawn jigging on stacked schools.
How they feed in the Keys
Blackfin tuna are the everyday Keys tuna — 15–35 lbs typical, occasional 40+ lbs. They school heavily over the Marathon and Islamorada humps and over deep structure 200–600 feet. Dawn vertical jigging on stacked schools is the classic Keys blackfin fishery. Chunk fishing on anchor with bonito chunks produces big fish through the day. They follow water-temperature breaks and the Stream edge.
72–82°F
Active 68–86°F
Less direct.
Strong current over the humps stacks bait and concentrates tunas.
Calm sunrise = peak. Wind chop under 3 ft.
Stable.
DAWN. The first hour of light over a hump = the year's best window. Mid-day fish on chunks.
Moderate lunar influence.
Moderate.
Marathon Hump and the Islamorada humps see fleets of boats at first light. Vertical butterfly or knife jigs (200–300 g) on PE 3–5 spinning gear is the standard.
Anchored over a hump with a bonito-chunk slick produces dawn-to-dusk steady action. Light leader (40 lb fluoro), small hook, dropped chunks.
12-month outlook
What they eat, what catches them
Vertical jig (200–300 g)
Butterfly or knife jig in mackerel, sardine, or chrome. Fast retrieve from bottom.
Live pilchards
Free-lined or under a balloon over the hump. Big fish target.
Bonito chunks
Cut and chunked into a slick. Drop a chunked bait into the slick on a 4/0 circle.
- Trolled cedar plugs / feathers· Search-mode trolling on the way out.
- Live ballyhoo· Productive when a school is busting bait on the surface.
- Dawn jigging over a hump
200 g knife jig on a PE 4 spin rod. Drop to bottom, fast jig 20 cranks up, drop again. Stay over the hump.
- Day chunk-fishing
Anchored over the hump + bonito chunks in the slick + 4/0 circle hook on a chunk free-lined back.
How top captains rig it
Spin: 50–65 lb braid (PE 3–5) for jigging.
Strong-drag spin: 8000+ size with smooth heat-resistant drag.
Jigging rod 6'–6'6" rated PE 3–5.
40–60 lb fluorocarbon, 4–6 ft.
- Hump jigging
PE 4 jigging rod + 50 lb braid + 50 lb fluoro + 200 g jig + 2-hook assist.
Recreational rules
No size limit.
2 per harvester per day in Atlantic state and federal waters.
Open year-round; HMS Atlantic permit required.
Spearing legal in many federal areas.
Note · HMS Angling permit required (free online). Bag limit changed in recent years — verify current rule.
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.