Also known as
- Southern Bluefin US
- SBT US
Identification
A massive Southern Hemisphere temperate-water tuna with a thick-shouldered torpedo build engineered for ocean-basin migration and brutal sustained runs.
- Blackish-blue back with metallic sheen, silvery-white belly with rows of clear dots and lines
- Yellow anal fin and finlets edged with black
- First dorsal fin yellow to bluish
- Shorter pectoral fins than other large tunas
- Prominent caudal keels on either side of the tail base
Where it holds
- Offshore
- Oceanic
Behaviour
A Southern Hemisphere cold-temperate ocean-basin migrator hunting open water between 30°S and 60°S. Endothermic adaptations sustain activity in 5-20°C (41-68°F) water that excludes most pelagic predators. Capable of dives over 1000m but feeds mainly 0-200m on baitfish and squid. Schools by size when immature, more solitary with age. Long-lived (40+ years), slow-growing. Annual migration to tropical waters for spawning.
Diet: Pilchards, Anchovies, Saury, Small Mackerel, Krill, Squid
How it's caught
Line Fishing
Trolling
The dominant Southern Hemisphere approach — particularly Portland and Tasmania, NZ East Cape, and the Cape of Good Hope. Pull a staggered spread of medium and large skirted lures, slant heads, and rigged pilchards at 6-9 knots along temperature breaks, current edges, and offshore islands. 24-37kg gear standard; 60kg for trophy class fish. Watch for diving birds, slick patches, and bust-up activity.
Chunking
The legendary Tasmanian and Portland cube-trail approach — anchor or drift along productive shelf-break ground and establish a steady cube trail of cut pilchards or squid down-current. Drop unweighted pilchard chunks on 8/0-10/0 non-offset circle hooks back through the trail. 24-37kg gear with long fluorocarbon leaders. The cube-trail revolution rewrote SBT charter fishing.
Jigging
Highly effective when fish hold deep at 30-80m on shelf breaks or in heavy current. Drop a 200-500g knife jig or slow-pitch jig to mark and rip with sharp 1-2m cadence. PE5-8 braid with 5-7m of fluorocarbon topshot. Speed jigging is deadly on aggressive fish.
Live Lining
A trophy-class approach when bait schools concentrate fish. Slow-troll or drift a live skipjack, slimy mackerel, salmon, or large squid on a 10/0-12/0 non-offset circle hook with sliding-sinker rig for depth control. Bridle the bait for tail action. Heavy 37-60kg gear with wind-on fluorocarbon leader.
Spear Fishing
Bluewater Spearfishing
An elite Southern Hemisphere bluewater target — South Australian and NZ spearos use burley trails to bring schooling fish into shooting range from a drift boat. Surface-active fish during summer current edges provide the encounter window. Use a 150-160cm bluewater speargun with 9.0mm shaft, slip-tip, breakaway rig, and 100L+ float system. Hard fast deep runs after the hit.
