© Shutterstock

Tunas are fast -

Some tuna species, like the Atlantic bluefin, can reach speeds of up to 47 mph (75 km/h), allowing them to outswim predators and chase down fast-moving prey across the open ocean.

© Shutterstock

Streamlined for power -

Tuna have torpedo-shaped bodies, stiff tails, and retractable fins, all designed to reduce drag. This makes them perfectly adapted for long-distance swimming and sudden bursts of speed.

© Shutterstock

Warm-blooded advantage -

Unlike most fish, some tunas can regulate their body temperature. This partial warm-bloodedness lets them survive in colder waters and gives them a predatory edge in varied environments.

© Shutterstock

They never stop swimming -

Tunas need constant motion to breathe. They rely on ram ventilation, meaning water must continuously pass through their gills. If they stop swimming, they could suffocate.

© Shutterstock

Masters of migration -

Tunas are oceanic travelers. Bluefins have been tracked swimming over 5,000 miles (8,000 km) across oceans, returning to the same spawning grounds year after year with remarkable accuracy.

© Shutterstock

Tuna can grow massive -

Atlantic bluefin tunas are the largest, reaching over 10 feet (three meters) in length and weighing more than 1,500 lbs (680 kg).

© Shutterstock

Camouflaged in the sea -

Tuna bodies are dark on top and silvery underneath. This countershading helps them blend into the ocean from above and below, confusing both predators and prey.

© Shutterstock

Excellent sense of smell -

Tuna have an acute sense of smell. This helps them detect prey, mates, and predators from long distances, even when visibility in the water is low.

© Shutterstock

Metabolism on overdrive -

Tunas have a high metabolic rate to support their constant movement. This enables them to digest food rapidly and stay active even during long ocean migrations.

© Shutterstock

Meat-eating machines -

Tuna are carnivores, feeding on fish, squid, and crustaceans. As top predators, they help maintain balance in marine ecosystems by controlling populations of smaller species.

© Shutterstock

They live long lives -

Bluefin tuna can live more than 40 years. However, due to overfishing, few reach old age. Their long lifespans also mean they reproduce more slowly than smaller fish.

© Shutterstock

Egg factories of the sea -

Female tuna can lay millions of eggs each spawning season. Despite this, only a few survive to adulthood due to predation and environmental conditions.

© Shutterstock

Born in warm waters -

Most tuna species spawn in tropical or subtropical seas. These warm areas provide the ideal conditions for fast development of eggs and larvae in their early life stages.

© Shutterstock

Tuna is a global food -

Tuna is one of the most consumed fishes in the world. It's enjoyed in sushi, steaks, and cans, making it a culinary staple in many cultures.

© Shutterstock

Japan's sushi prize -

In Japan, high-grade bluefin tuna is a luxury delicacy. Some whole tunas have sold at auction for around US$1.3 million, highlighting their cultural and economic value.

© Shutterstock

Worth more than gold -

Top-grade bluefin tuna can cost more per kilo than gold. This makes them a lucrative target for commercial fisheries, despite their declining populations.

© Shutterstock

Facing serious threats -

Due to overfishing, particularly for luxury markets, bluefin tuna are critically endangered. Their slow growth and high value make them especially vulnerable to extinction.

© Shutterstock

Tuna fishing and dolphin bycatch -

Tuna fishing often harms dolphins, especially in the eastern Pacific, where dolphins swim with yellowfin tuna. Millions have died as bycatch, and about 80,000 are still killed each year.

© Shutterstock

Tracking tuna via satellite -

Scientists tag tunas with satellite transmitters to study their migratory paths, behavior, and habitat use. This data helps inform conservation efforts and sustainable fisheries' management.

© Shutterstock

Tuna school together -

Tuna often swim in large schools by size. This behavior confuses predators, makes hunting more efficient, and is sometimes exploited by fishermen to catch them in bulk.

© Shutterstock

Eco-health indicators -

Tunas are top predators in the ocean, so their health shows how the ocean is doing. If tuna numbers go down, it can mean there are problems like overfishing, pollution, or changes in the climate.

© Shutterstock

Many species of tuna -

There are 15 known tuna species. These include bluefin, yellowfin, skipjack, bigeye, and albacore, each differing in size, behavior, habitat, and commercial value.

© Shutterstock

Skipjack tuna dominates cans -

Skipjack tuna is the most commonly canned species. It's smaller, reproduces quickly, and has a mild flavor, making it popular and more sustainable than bluefin or bigeye.

© Shutterstock

White tuna confusion -

"White tuna" on a menu is often actually albacore tuna, known for its light-colored flesh. True white tuna (escolar) is a different species and can be mislabelled.

© Shutterstock

Mercury warning -

Larger tuna species, like bluefin and bigeye, accumulate mercury. While fine in moderation, excessive consumption, especially by pregnant women, can pose health risks due to the presence of this toxic metal.

© Shutterstock

Why tuna meat is red -

Unlike many fish, tuna meat is red or pink due to high levels of myoglobin, a protein that stores oxygen in their muscle tissue for endurance swimming.

© Shutterstock

Deep sea divers -

Some tunas, like bigeye, can dive to depths over 1,640 feet (500 meters). They descend into colder, darker waters to hunt squid and other deep-sea prey.

© Shutterstock

Science-based conservation -

Tag-and-release programs help researchers monitor tuna migration, spawning, and population health. This data is critical to developing international policies for sustainable fishing.

© Shutterstock

Tuna farming challenges -

To reduce fishing pressure, tuna farming—raising juveniles in sea pens—is being explored. However, it's controversial due to high feed demands and questions around sustainability.

Sources: (National Geographic) (World Wildlife Fund) (Britannica) 

See also: The food industry's biggest scandals

© Shutterstock