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Thunnus tonggol collected off Ormara, Pakistan.

Longtail tuna

A slender tropical tuna of the Indo-West Pacific.

Photo: Muhammad Moazzam Khan, CC BY 3.0, via Wikimedia Commons

The longtail tuna is a species found in tropical Indo-West Pacific waters. It grows slower and lives longer than similar tunas, which may increase its risk from overfishing. It reaches up to 145 centimetres in length.

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  • Reaches 145 cm in length and 35.9 kg in weight
  • More slender with shorter pectoral fins than bluefins
  • Slower growth and longer lifespan than similar tunas
  • Found in tropical Indo-West Pacific waters

What it is

The longtail tuna is a member of the tuna family found in tropical regions. It has a more slender body shape than other large tunas. Its pectoral fins are shorter in proportion to its body. This species can grow up to 145 centimetres long and weigh nearly 36 kilograms. It is distinct from the Atlantic and North Pacific bluefin species.

Where it lives

This fish inhabits the tropical waters of the Indo-West Pacific. It is found across this broad marine region. The specific name northern bluefin tuna is used in Australia to separate it from the southern bluefin tuna. This local naming convention helps distinguish it within regional fisheries but causes confusion with other bluefin species globally.

How it lives

Compared to other tunas of similar size, this species exhibits slower growth rates. It also has a longer lifespan than its counterparts. These biological traits suggest it may be more susceptible to pressure from fishing activities. The slower recovery rate means populations might not rebound quickly if heavily exploited.

Longtail tuna
A drawing made by EveryFish from what this page says. It is a diagram, not a picture of the real fish.

Fish and people

In Australia, it is often called the northern bluefin tuna. This name distinguishes it from the southern bluefin tuna caught in nearby waters. However, this label leads to confusion with the true bluefins of the Atlantic and North Pacific. It is a target for fisheries in its range due to its size and meat quality.

Status and threats

The slower growth and longer life of this tuna may make it vulnerable to overfishing. Unlike faster-growing species, it takes more time to replace individuals removed from the population. This biological characteristic requires careful management to ensure sustainable catches in the Indo-West Pacific region.

Questions people ask about Longtail tuna

Where does the longtail tuna live?

It is found in the tropical waters of the Indo-West Pacific. This range covers a vast area of warm ocean habitats where the species thrives.

Why is it called northern bluefin tuna in Australia?

The name is used in Australia to distinguish it from the southern bluefin tuna. However, this causes confusion with the Atlantic and North Pacific bluefin species.

How big does the longtail tuna get?

It can reach a maximum length of 145 centimetres. The maximum recorded weight for this species is approximately 35.9 kilograms.

Good reading and sources

Where this page comes from

The facts on this page come from the Wikipedia article "Thunnus tonggol", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.

It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.

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Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.

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