Also known as
- Blackfin US
- Bermuda Tuna US
Identification
A compact Caribbean and Western Atlantic tuna — the smallest of the Thunnus tunas but disproportionately powerful, built for blistering runs. Males and females reach similar sizes.
- Dark blue to black on top — the darkest of the tunas
- Iridescent silver sides with a faint yellow lateral stripe
- All-dark second dorsal and anal finlets — uniformly dark, lacking the yellow finlets of yellowfin
- Short pectoral fins relative to body size
- Compact body with strong caudal keels
Where it holds
- Oceanic
- Inshore
Behaviour
A surface-oriented schooling pelagic — far more coastal than other Thunnus tunas. Found within sight of shore at oil rigs, weed lines, reef edges, and shelf breaks in 0-50m, rarely diving deep. Forms compact fast-moving schools that herd bait into surface bust-ups, attracting frigatebirds and terns that mark productive water. Visual predator with excellent eyesight in clear oceanic water. Peak activity above 21°C (70°F); migrates seasonally to track warm water.
Diet: Sardines, Anchovies, Ballyhoo, Flying Fish, Small Herring, Squid
How it's caught
Line Fishing
Live Lining
The premier approach worldwide — particularly Florida Keys, Louisiana oil rigs, Bahamas, and the Eastern Caribbean. Free-line a live sardine, pilchard, goggle eye, or threadfin herring on a 4/0-6/0 non-offset circle hook with a long fluorocarbon leader. Kite fishing from drift boats places multiple baits on the surface — devastating when fish are concentrated. Bridle the bait for maximum tail action.
Trolling
A high-mileage approach for finding scattered fish — slower than other tuna trolling at 5-6 knots. Pull a spread of small skirted lures, feathers, cedar plugs, and rigged ballyhoo behind sea-witch teasers along weed lines, oil rigs, temperature breaks, and reef edges. 6-15kg gear with fluorocarbon leaders.
Jigging
Deadly when fish hold deep at the thermocline or below surface activity. Drop a 60-150g chrome diamond jig or metal jig to mark and rip with sharp 1-2m cadence pauses. Effective midday when surface activity dies. PE2-4 braid with 4-5m of fluorocarbon topshot.
Chunking
An anchor-up oil-rig and shelf-break standard. Establish a steady chum slick of cut sardines, mackerel, or herring while drifting or anchored, then drop unweighted chunks on 4/0-5/0 non-offset circle hooks at varying depths in the slick. Long fluorocarbon leaders and a slow patient drift produce the bigger fish.
Spinning
Exhilarating sight-cast approach to surface bust-ups under birds. Pitch 80-150g small poppers, stickbaits, or weighted soft plastics into breaking fish. Aggressive walk-the-dog or fast-pop retrieves trigger explosive strikes. Scale down lures versus other tunas.
Spear Fishing
Bluewater Spearfishing
A productive Caribbean bluewater target — surface-school behaviour and clear water make encounters more accessible than deep-water tunas. Burley with cut bait and intercept incoming schools from the surface. Use a 100-120cm bluewater speargun with 7.0mm shaft, slip-tip, breakaway rig, and float-line into a hard float.
