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Fun Thunnus Facts For Kids

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Thunnus is not the name of any type of animal, instead, it is a genus of ray-finned marine fishes that belong to the mackerel family. They refer to the popular tuna fish. Some common tunas are bluefin tuna, yellowfin tuna, and blackfin tuna. The bluefin tuna having the scientific name Thunnus thynnus is the representative species. The population of Atlantic bluefin tuna comprises the stock of tuna fish in the eastern and the western Atlantic Ocean. The population of the eastern stock had a higher magnitude than the western Atlantic bluefin tuna.

The main threat that decreased the number the Atlantic bluefin tuna species from the wild is overfishing. The catch size of the eastern Atlantic ocean increased up to 31 mi (50000 m) in 1990 but decreased to 6.21 mi (10000 m) by 2012. The western Atlantic population is globally threatened. The yellowfin tuna has a wider range in comparison to other tunas in the world. On the other hand, the bigeye tuna (Thunnus alalunga) is an endangered species. To know more facts about these fish, keep on reading these facts.

For similar content check out black ghost knifefish and royal gramma facts too.

Fun Thunnus Facts For Kids

What do they prey on?

Shrimp, squid, kelp, crustacean, and stomatopod

What do they eat?


Average litter size?

Up to 10 million eggs in a season

How much do they weigh?

550 lb (250 kg)

How long are they?

Up to 6 ft (1.82 m)

How tall are they?


What do they look like?

Silvery white belly, yellowish and reddish dorsal and anal fins

Skin Type


What were their main threats?


What is their conservation status?

Atlantic bluefin tuna - Least Concern

Where you'll find them?



Atlantic And Pacific Ocean









Thunnus Interesting Facts

What type of animal is a Thunnus?

Thunnus is a genus of fish known as tuna fish.

What class of animal does a Thunnus belong to?

The Thunnus of Scombriformes order and Scombridae family belong to the class Actinopterygii.

How many Thunnus are there in the world?

The global population of all species of the genus Thunnus together has not been quantified. Therefore, the total population of Thunnus is unknown. The population structure of different species is affected by the physical environment of their habitat, and their population trend varies drastically. For example, the Atlantic bluefin tuna is a widespread tuna and one of the most common species of Thunnus. The global catch size of the yellowfin tunas is very large and it has further increased in recent years. The blackfin tunas are one of the most common tuna in the world. They are abundant in longline fisheries and the population of the blackfin seems to be stable.

Where does a Thunnus live?

The distribution of the tunas is divided into two subpopulations, one that belongs to the Atlantic and one belonging to the Pacific. The Atlantic tuna fish extends over a large area ranging southwards from the south of Newfoundland and Labrador in the north. In the Western Atlantic, they extend from the Gulf of Mexico and the Caribbean Sea up to Venezuela and Brazil off the South American coast. In the eastern Atlantic, their distribution ranges from the Lofoten islands around the coast of Norway in the north up to the Canary Islands and the Mediterranean sea in the south. The Pacific tuna range extends off the coast of Alaska up to southern California in the east and from south Okhotsk sea up to the northern Philippines in the west.

What is a Thunnus's habitat?

The Thunnus habitat is the same for almost all species of the Scombridae family. The sea-based Thunnus fish might come to the shores during their seasonal movements. Apart from that, they are strictly pelagic to epipelagic fish of the ocean. The bluefin tuna has an acceptance of widely varying water temperatures, they are often seen together in schools containing albacore (Thunnus obesus), skipjack, yellowfin, and frigate tuna. They have wide ranges and occupy tropical, subtropical, and temperate waters. All the species are highly migratory and their course of migration depends on the temperature of the water.

Who does Thunnus live with?

The tunas of the genus Thunnus are strongly schooling fish. Most of the species show schooling behavior not only with the same species but also along with other tunas that cross each other's range.

How long does a Thunnus live?

The Pacific bluefin tuna can live up to 26 years of age but the average lifespan is 15 years old. The yellowfin tuna has a lifespan of about seven tears while the Atlantic bluefin tuna species has a long lifespan of up to 20 years. The blackfin tuna is a short live fish species in comparison to other tuna species that live for only five years. All of them are migratory in nature. Migration takes place in large aggregations. The schools migrate to the cool waters of the north during the summer months.

How do they reproduce?

The spawning season of the blackfin tuna lasts from April to November on the Florida coast and from June to September in the Gulf of Mexico. The breeding season of the bluefin tuna lasts from April to June in the Gulf of Mexico when the blackfins breed off the Florida coast and June to August in the Mediterranean. The yellowfin tuna on the other hand breeds throughout the year with breeding activities reaching the peak in the summer months. The spawning mechanism of the tuna fish of the Scombridae family is the same for all species. The males and the females produce sperms and eggs respectively at the same time in the water column. The eggs released by the female fish are fertilized externally by the sperm released by the male fish. Therefore, fertilization occurs outside the body by a process known as external fertilization. The buoyant eggs float on the water and the juvenile fish coming out of it live in the open sea. A female tuna can spawn almost daily and each time they spawn they can release millions of eggs. At the end of the season, the females release ten million eggs from its body but only a few of them survive till maturity. The tunas sexually mature between four to eight years of age.

What is their conservation status?

The Atlantic bluefin tuna, yellowfin tuna, and blackfin tuna are listed as species of Least Concern in the IUCN Red List. The global population size of the Atlantic bluefin tuna has not declined significantly in the past three years. Instead, the eastern population of the species which comprises 80% of the global population seems to be increasing. The western Atlantic population, however, decreased at an alarming rate over the years. They are subject to continued overfishing since 2018. The yellowfin tuna population declined by 8-17 % in the last 10-14 years but since the last three generations, their population decline remained less than 17% and the yellowfin species are classified as Least Concern. Even though the Atlantic bluefin tuna is threatened in the west Atlantic, the blackfin species are found there in large numbers. There is no evidence of consistent population decline of the blackfin tuna though there are some citations of declines reported in their range. The population trend of the blackfin tuna species needs to be monitored closely. The other species of the genus Thunnus, like southern bluefin tuna have been classified as an Endangered species recently in the IUCN Red List while the Pacific bluefin tunas are listed as Near Threatened species in the Red List. Bigeye tuna (Thunnus alalunga) is an Endangered species.

Thunnus Fun Facts

What does Thunnus look like?

The Thunnus genus consists of large fish species with a deep body around the dorsal fin. The second dorsal fin is greater in length than the first dorsal fin. The pectoral fins are very short, they do not even reach the space between the dorsal fins. The color of the lower parts of the tunas is silvery white. They are striped by colorless transverse lines throughout the body and accompanied by colorless dots in the belly. The color of the first dorsal fins varies from yellow to bluish while the second dorsal fin is slightly reddish in color. The anal fins are dusky yellow and are bordered by black.

Thunnus under water

How cute are they?

The tuna fish are used as food sources so rating them on their cuteness is not justified.

How do they communicate?

The tuna has very good sight. They communicate and locate their prey by their developed vision.

How big is a Thunnus?

The yellowfin and bluefin tuna have an average length of 6 ft (1.82 m). They are much larger in length than the blackfin tuna which is around 39 in (100 cm).

How fast can a Thunnus swim?

The tunas are swift swimmers in the sea. The bluefin tuna can swim at speeds up to 43 mph (69.2 kph). The yellowfin tuna can swim as fast as 50 mph (80.46 kph). The blackfin tunas are also very fast and they swim at a speed of 46 mph (74 kph).

How much does a Thunnus weigh?

The average weight of a yellowfin tuna is 400 lb (181.43 kg) while a bluefin tuna is 550 lb (250 kg).

What are the male and female names of the species?

The male and the female do not have any specific names. Both of them are known referred to as tunas.

What would you call a baby Thunnus?

A baby fish of the Thunnus genus is called a fry.

What do they eat?

Equipped with strong teeth, the Thunnus species are carnivorous in nature, the food consists of other oceanic creatures. The bluefin tuna feeds on kelp. The food of yellowfin tuna includes other fish species, squid, and crustaceans while the food of blackfin tuna includes shrimp, crab, and stomatopods. The juveniles feed on zooplankton.

Are they aggressive?

No, they are not aggressive.

Would they make a good pet?

No, they do not make good pets.

Did you know...

The bluefin tuna breeds by forming large aggregations. Many individuals produce sperms and eggs at the same time which results in mating with several individuals. This is known as broadcast spawning.

What does Thunnus mean?

The Thunnus genus is one of the five genera that comprise the tribe of thunnini or tuna. It is a common name that is used for denoting a group of seven different tuna fish found in different parts of the world.

How is it different from other fish of the mackerel family?

Tuna and mackerel are both edible fishes that are enjoyed by humans for their taste. There are some differences in taste between mackerel and tuna. However, some tuna fish can be prickly pears consisting of thorns in their body. Mackerel is edible so they do not contain any thorns.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! For more relatable content, check out these dogfish shark facts and rasbora for kids.

 You can even occupy yourself at home by coloring in one of our free printable bluefin tuna coloring pages.

Second image is by Gustavo200897.

Written By
Moumita Dutta

Moumita is a multilingual content writer and editor. She has a PostGraduate Diploma in sports management, which enhanced her sports journalism skills, as well as a degree in journalism and mass communication. She's good at writing about sports and sporting heroes. Moumita has worked with many soccer teams and produced match reports, and sports is her primary passion.

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