Bluefin Tuna
Atlantic bluefin tuna are the centrepiece of Canada's east coast big-game fishery. Western Atlantic fish feed in Canadian waters through summer and fall, with the Gulf of St.
Lawrence, Northumberland Strait, Bay of Fundy, and waters off Nova Scotia and Prince Edward Island all producing giants. Fish commonly run 400–900 pounds, and four-figure weights are real here.
Scientific Name: Thunnus thynnus
Also known as Giant bluefin, northern bluefin, tunny
- Deep, torpedo-shaped body with a dark metallic blue back, silvery-white belly, and short, bright yellow finlets running to the tail — unmistakable at boatside.
- Retractable pectoral fins are notably short compared to other tuna species — a key field mark that separates bluefin from yellowfin or bigeye.
- Most fish encountered in Canadian waters weigh 400–900 lb; fish exceeding 1,000 lb are caught regularly, with the species reaching a documented 1,500 lb.
- Average weight in PEI and Nova Scotia charter fisheries runs around 750 lb — these are genuinely large animals, closer in size to a horse than a typical gamefish.
What to know
Habitat Distribution
- Native to the western Atlantic; the Canadian population is part of the western Atlantic stock, with greater than 99% of fish in Canadian waters tracing their origins to Gulf of Mexico nursery grounds.
- Summer and fall feeding grounds span the Gulf of St. Lawrence, Northumberland Strait, St. George's Bay, Bay of Fundy, and offshore Nova Scotia — wherever bait concentrates near the surface.
- Highly migratory: fish arrive in Atlantic Canadian waters to feed in summer, then move south to the Gulf of Mexico for winter and spawning.
- Open pelagic water is their domain — they follow bait schools near the surface but can dive deep; they're not a structure fish in the conventional sense.
Key Locations
- Prince Edward Island (Northumberland Strait, Tignish area) — one of the most active charter fisheries in Canada, with fish running July through October.
- Canso, Nova Scotia — a well-known hotspot with a long history of giant bluefin; charter operations run full-day trips from here.
- Bay of Fundy and St. Margarets Bay, NS — historically productive grounds documented in DFO catch records.
- Gulf of St. Lawrence broadly, including St. George's Bay — the wider feeding range that connects PEI and Nova Scotia grounds.
- Wedgeport, Nova Scotia — historically called the "Sport Tuna Fishing Capital of the World" and home to one of the earliest tuna tournaments in North America.
Specific Spots
- Wherever mackerel and herring are schooling near the surface — bluefin stack up beneath and around bait balls, so watch for diving gannets and surface commotion.
- Temperature breaks and current edges in the Gulf of St. Lawrence and off Nova Scotia concentrate bait and hold feeding fish; captains run sea-surface temperature charts hard.
- Shallow inshore grounds around PEI's Northumberland Strait and Canso, NS can hold fish surprisingly close to land when bait pushes in — don't assume you need to run far offshore.
- Chum slicks drifted behind anchored or slow-drifting boats draw fish up from depth; once a slick is working, fish will come to the boat.
Bluefin Tuna FAQ
Answers from onWater's species guide.
What are the best lures and bait for Bluefin Tuna?
Chunked or whole mackerel and herring are the go-to baits in a chum slick, fresh is better than frozen, and matching the size of the chunk to what's in the slick matters.
When is the best time to fish for Bluefin Tuna?
Season runs July through October in Atlantic Canadian waters, with fish arriving as bait schools build through summer. Peak fishing is September and October, fish are at their largest and most concentrated before the southward migration.
How do you catch Bluefin Tuna?
The dominant approach in Canada is boat fishing with a guide or charter captain, the fish, the gear, and the distances involved make DIY trips uncommon. Most trips involve anchoring or slow-drifting while running a mackerel chum slick, then presenting baited circle hooks at various depths in the slick.
What do Bluefin Tuna eat?
Mackerel and herring are the primary forage in Canadian waters, when fish are feeding on these, chunked or whole mackerel on a circle hook in a chum slick is the most direct presentation you can make.
Where do Bluefin Tuna live?
Native to the western Atlantic; the Canadian population is part of the western Atlantic stock, with greater than 99% of fish in Canadian waters tracing their origins to Gulf of Mexico nursery grounds. Summer and fall feeding grounds span the Gulf of St. Lawrence, Northumberland Strait, St.
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