The nuclear explosion that changed the course of history
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.
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.
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.
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.
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.
Tuna are more than just a popular sandwich filling or sushi favorite, they’re fast, powerful, and play a big role in ocean ecosystems. Found in warm seas around the world, these mighty fish are built for speed and endurance, with some species migrating thousands of miles each year. Tuna are also vital to global diets and economies, making them one of the most commercially valuable fish.
Click in for some fascinating facts about these impressive ocean swimmers.
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.
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.
Atlantic bluefin tunas are the largest, reaching over 10 feet (three meters) in length and weighing more than 1,500 lbs (680 kg).
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.
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.
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.
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.
Female tuna can lay millions of eggs each spawning season. Despite this, only a few survive to adulthood due to predation and environmental conditions.
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.
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.
Due to overfishing, particularly for luxury markets, bluefin tuna are critically endangered. Their slow growth and high value make them especially vulnerable to extinction.
Top-grade bluefin tuna can cost more per kilo than gold. This makes them a lucrative target for commercial fisheries, despite their declining populations.
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.
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.
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.
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.
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.
There are 15 known tuna species. These include bluefin, yellowfin, skipjack, bigeye, and albacore, each differing in size, behavior, habitat, and commercial value.
"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.
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.
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.
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.
Tag-and-release programs help researchers monitor tuna migration, spawning, and population health. This data is critical to developing international policies for sustainable fishing.
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
Totally tuna: interesting facts about the mighty fish
An in-depth look at one of the ocean's most remarkable creatures
messages.DAILYMOMENT Animals
Tuna are more than just a popular sandwich filling or sushi favorite, they’re fast, powerful, and play a big role in ocean ecosystems. Found in warm seas around the world, these mighty fish are built for speed and endurance, with some species migrating thousands of miles each year. Tuna are also vital to global diets and economies, making them one of the most commercially valuable fish.
Click through the gallery for some fascinating facts about these impressive ocean swimmers.