Did You Know There Are TWO Kinds of Bluefin Tuna?

Okay, quick question for everyone 😊

Did you know there are actually TWO different kinds of bluefin tuna 🐟⁉️

Honestly, until pretty recently, I had no idea 😅💦

I always thought “bluefin tuna” was just one single fish. But it turns out they are two completely separate species 🤯❣️

Let me explain — bear with me 🙇‍♀️

The bluefin we catch and eat most often here in Japan is the Pacific bluefin tuna 🌊

Its scientific name is Thunnus orientalis.

The famous big tuna caught around Japan are all this species 😊💗

The other one is the Atlantic bluefin tuna 🌍

Its scientific name is Thunnus thynnus.

This is the kind caught in the Mediterranean and off the Atlantic coast of North America — like the famous giant bluefin of New England and Nova Scotia 😳

They look almost identical, but they are classified as two different species ✌️

Who knew 😂

And here’s the interesting part 😁

These two species grow to different maximum sizes 💪🧡

The Atlantic bluefin tuna (Thunnus thynnus) can reach up to about 680 kg (1,500 lb) and around 3 m (10 ft) long 😱

That’s basically the size of a small car 🚗⁉️

The Pacific bluefin tuna (Thunnus orientalis) maxes out at about 450 kg (990 lb) and a similar 3 m length 🐟

(Sources: Pacific bluefin data from NOAA, Atlantic bluefin data from FAO)

But hold on — 450 kg is still absolutely massive 🥹❣️

Pacific bluefin are nothing to underestimate. Fish over 200 kg are common, and 300 kg giants show up too 🔥

Still, species to species, the Atlantic bluefin grows just a bit bigger. That part is a fact 😌

So why does the Atlantic bluefin get so big 😳❓

Good question 💡

It turns out the Atlantic bluefin is extremely fatty and can survive in cold water as low as 7–8°C (about 45°F) 🥶

(Source: National Museum of Nature and Science, Japan)

Those cold, nutrient-rich northern waters are full of oily prey like herring and mackerel 🐟🐟

By eating tons of that rich food, they pack on size and fat — that’s the leading idea, anyway 😋

In fact, off Norway in the Atlantic, the average bluefin is reported at around 270 kg (about 600 lb) 🤯

(Source: Wedge)

An AVERAGE of 270 kg — I can’t even picture it 😂💦

Cold water + rich food = giant tuna 🥹❣️

And here’s the coolest part 💁‍♀️

Where do you think the world-record bluefin was caught 😏❓

The answer is… off Nova Scotia, Canada 🇨🇦‼️

Back in 1979, an angler named Ken Fraser landed a 678.58 kg (1,496 lb) Atlantic bluefin — and it’s STILL the IGFA world record today 🏆✨

(Source: IGFA World Records)

Almost half a century later, no one has beaten it 😳 Incredible 💦

One quick but important note ☝️

It’s not that North America makes them bigger — it’s that the Atlantic side of North America is home to the Atlantic bluefin, the bigger species 🥹

North America also has a Pacific side (off California), and the bluefin caught there are Pacific bluefin 🌊

So Nova Scotia = Atlantic side = Atlantic bluefin = largest species. That combination is why the world record comes from North America 😊👏

Pretty fascinating 🥹❣️

Now for the question you’re probably wondering 😋

Which one tastes better 💗

This part was fun to research ☺️

According to tuna wholesalers in Japan, the Atlantic bluefin has a rich, intense flavor 🧡 — fattier and bolder 😋

(Source: Tsukiji tuna wholesaler blog)

The Pacific bluefin, on the other hand, is prized by top sushi chefs for its clean, delicate flavor that pairs beautifully with vinegared sushi rice 🍣✨

(Source: sushi blog)

So it’s rich-and-bold Atlantic vs. clean-and-elegant Pacific 😊

Honestly, it comes down to personal taste 🥹💦

For sushi, I think I lean toward that clean, delicate Pacific bluefin 😋💗

But I’d love to try a big, rich slab of Atlantic bluefin at least once 🤤❣️

It’s not about which is “better” — they each have their own charm 😊👏

So, what did you think 😁❓

Even as someone who fishes, I was genuinely surprised that there are two kinds of bluefin tuna 🤯

Pacific bluefin and Atlantic bluefin — same nickname, but different species, different maximum sizes, and even different flavor personalities 🐟💞

It makes me dream of one day meeting a giant Atlantic bluefin on the other side of the world 🥹🌍✨

Next time you see bluefin at a sushi restaurant or fish market, try guessing — Pacific or Atlantic? It makes it a little more fun 😋💗