News
SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliamentSpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliament
EveryFish
Thunnus_obesus Longline fishing research on the NOAA Ship OSCAR ELTON SETTE. Bigeye tuna.

Bigeye tuna

Deep-bodied tuna of tropical and temperate oceans.

Photo: Allen Shimada, NOAA NMFS OST, Public domain, via Wikimedia Commons

The bigeye tuna is a large species of true tuna found in open waters worldwide, excluding the Mediterranean. It possesses unique physiology for deep-water foraging and faces significant pressure from industrial fisheries, leading to overfished status in several regions.

Share on WhatsApp

  • Can grow up to 2.5 m in length and weigh over 180 kg
  • Tolerates low oxygen levels down to 1.0 mL/L in deep water
  • Overfished in western and central Pacific and eastern Pacific
  • Added to Greenpeace seafood red list in 2010
  • Undertakes daily vertical shifts to depths of 500 m

What it is

This species belongs to the genus Thunnus within the mackerel family Scombridae. It features a deep, streamlined body with a large head and prominent eyes. The pectoral fins are notably long, extending beyond the second dorsal fin in juveniles. Adults have thirteen or fourteen dorsal spines. These fish can reach lengths of 2.5 metres and weigh over 180 kilograms. Their physical structure supports life in open ocean environments across tropical and temperate zones.

Where it lives

Bigeye tuna inhabit open waters in all tropical and temperate oceans but are absent from the Mediterranean Sea. They perform daily vertical migrations, moving to depths of 300 to 500 metres during daylight hours. In the eastern Pacific, they spend most time between 200 and 350 metres. Around Hawaii, they prefer 300 to 400 metres, while in the Coral Sea, they dive to 300 to 500 metres. They track optimal temperatures of 10 to 15 degrees Celsius, which vary by region.

How it lives

These tuna feed on epipelagic and mesopelagic fish, crustaceans, and cephalopods. Their diet often includes species that migrate vertically, linking their movement to prey availability. They associate with seamounts, buoys, and fish aggregating devices for periods of ten to thirty days. During these associations, they remain in surface waters. Tagging studies show they can cross entire ocean basins yet maintain site fidelity to specific regions. Central Pacific populations migrate from subtropical to tropical waters seasonally.

Breeding and life cycle

Spawning occurs throughout most months in tropical Pacific regions. At higher latitudes, it becomes seasonal when sea surface temperatures exceed 24 degrees Celsius. In the northwestern Atlantic, spawning happens in June and July. The Gulf of Guinea serves as the only known Atlantic nursery, with spawning in January and February. Sexual maturity varies geographically, occurring at lengths of 102 to 135 centimetres. This corresponds to an age of two to four years. Maximum recorded age is sixteen years based on otolith growth increments.

Bigeye 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

Commercial vessels caught approximately 450,500 metric tonnes in 2012. Purse seine fleets dominate catches in the Pacific, while longline fleets lead in the Indian and Atlantic Oceans. Fisheries use fish aggregating devices, accounting for 27 per cent of western and central Pacific catches. The angling record stands at 178 kilograms. Regional bodies manage stocks, including the WCPFC and IATTC in the Pacific. Greenpeace International placed this species on its seafood red list in 2010 due to sustainability risks.

Status and threats

Stock assessments indicate the species is overfished in the western and central Pacific Ocean and the eastern Pacific Ocean. It is close to or currently overfished in the Atlantic Ocean. The Indian Ocean stock is not considered overfished. Catch rates have declined sharply over the past fifty years due to increased industrial fishing. Ocean warming adds stress by reducing marine phytoplankton, particularly in the Indian Ocean. Conservation measures include spatial closures and catch limits.

Thunnus obesus Lowe
Thunnus obesus Lowe. Photo: Lowe, Public domain, via Wikimedia Commons
Bigeye tuna Thunnus obesus caught with three-pole one-line rig (Tropical Pacific Ocean)
Bigeye tuna Thunnus obesus caught with three-pole one-line rig (Tropical Pacific Ocean). Photo: Bernard Frink, BCF, Public domain, via Wikimedia Commons
Bigeye tuna, Thunnus obesus , on ice
Bigeye tuna, Thunnus obesus , on ice. Photo: Unknown author, Public domain, via Wikimedia Commons
Longline fishing research on the NOAA Ship OSCAR ELTON SETTE. Bigeye tuna on sampling table
Longline fishing research on the NOAA Ship OSCAR ELTON SETTE. Bigeye tuna on sampling table. Photo: Allen Shimada, NOAA NMFS OST, Public domain, via Wikimedia Commons

Questions people ask about Bigeye tuna

How deep do bigeye tuna dive?

During the day, they typically descend to depths between 300 and 500 metres. These deeper waters are significantly cooler than surface layers. They return to shallower, warmer waters at dusk to re-warm their bodies.

What do bigeye tuna eat?

They primarily consume epipelagic and mesopelagic fish. Their diet also includes various crustaceans and cephalopods. Stomach contents often reveal diurnally migrating species, suggesting they follow prey movements.

Is bigeye tuna sustainable to eat?

Greenpeace International added it to its seafood red list in 2010. Stocks are overfished in the Pacific and near overfished in the Atlantic. Sustainability guides often recommend choosing other tuna types instead.

Where do bigeye tuna spawn?

Spawning occurs year-round in tropical Pacific regions. In the Atlantic, it happens in June and July in the northwest, and January and February in the Gulf of Guinea. Higher latitudes see seasonal spawning when water warms.

Good reading and sources

Where this page comes from

The facts on this page come from the Wikipedia article "Bigeye tuna", 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.

Like Bigeye tuna

All tunas and mackerels
🇺🇸 United States and 3 morePacific bonito Striped marine fish of the Pacific coastTuna · Coasts and shelves WorldMackerel A group of pelagic fish known for their speed, stripes, and role in global fisheries.Tuna · Open ocean WorldSouthern bluefin tuna Large migratory tuna of the southern oceans.Tuna · Open ocean WorldPacific bluefin tuna Large migratory tuna of the northern Pacific OceanTuna · Open ocean

More from Scombridae

All of them
WorldDogtooth tuna A large Indo-Pacific bonito prized by sport anglers.Tuna · Coasts and shelves WorldBullet tuna Small, slender tuna found in tropical oceans worldwide.Tuna · Open ocean WorldBlue mackerel A small, fast pelagic fish found in tropical Indo-Pacific waters.Tuna · Coasts and shelves Slender tuna WorldSlender tuna A southern ocean tuna with oily flesh and a slender build.Tuna · Open ocean

Photo credits on this page

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

The weekly digest

Every Monday: the fish of the day, new pages on EveryFish, and the conferences and anniversaries of the week ahead.