Common Tuna: Characteristics, properties, threats and more…

The common tuna has the scientific name Thunnus Thynnus, or as it is also known in other places of the world bluefin tuna, red tuna or patudo; as they usually call it in some Spanish Islands

It comes from the shores of the Atlantic Ocean , both western and eastern, and sometimes you can find it at the Mediterranean Sea.

Characteristics Of  The Common Tuna.

The common tuna, is considered one of the largest fish  in the world. It has  two dorsal fins that can be yellowish or blue, and a second one dark brown or red, which differentiate it from other tuna .

These specimens have the capability to raise its internal  temperature , which allows them to get adapted to different ranges of temperature,  especially the cold ones. However the common tuna, is not a hot blood fish. They can submerge up to 900 meters deep to hunt their prey.

common tuna: pacific bluefin tunaIn terms of length, they can reach up to 3 meters, and weigh  600 kg. 

The common tuna  is characterized, by having a strong  body in its frontal portion, very small eyes with respect to other species, and a jaw that contains small teeth formed in a single row.

In its dorsal portion the common tuna presents bluish colorations almost black, with gray or greenish flashes, that disappear completely after dying. It is a very skilled and swift swimmer, that  can reach up to 30 km / h,  which makes it very capable of making long migrations.

In spring the common tuna  tends to migrate,  to the warm Mediterranean waters in order to reproduce, so this is the best season  to fish these specimen..

Its longevity is variable  and depends on the waters where they develop. However,  many studies show that they  can live between 20 and 30 years, that is because  they reach adulthood very slowly. There are species that are captured and bred in captivity,  which  only live 8 years,  so they barely reach the reproductive age.

Other studies show ,that under normal natural conditions, they  are able to exceed 30 years of age, however this information is not totally confirmed.  The longevity of these specimens, as we mentioned before; will depend on the waters where they  grow, since it is said that when they  coexist in western waters they can survive for a longer time.

Behavior Of The Common Tuna

The behavior of the  common  tunas  is  characterized , by the constant migrations they carry out in order to search for  food, and when they need to reproduce.

In terms of feeding, they usually form groups along with other tuna species, swimming then  through the Pacific Ocean for feeding purposes. When the reproduction time ends, the females common tuna usually return to the seas where they were born, to conceive their offspring. A single tuna can make several migrations, swimming from the Atlantic Ocean and crossing all the Pacific in Only 1 year.

Common Tuna Alimentation Habits 

The bluefin tuna is considered a powerful carnivore,  which during its migrations  feed on a wide variety of fish and shellfish, such as sardine, shrimp, mackerel, anchovies, herring, eels, octopus and jellyfish. They catch all their preys, in the different areas where they look for food; but they don´t  consume them daily.

As far as the hunting of big fish like eels, octopus and jellyfish; the common tuna usually consume them, when they are in their non-mature stage, since they can take better advantage of their sizes, and it is easier to hunt them.


The common tuna  reaches  its maturity, between 4 and 8 years; however it isn´t  yet fully verified,  that they begin to reproduce at this age.  Many specialist consider  that the reproduction could occur before

The reproduction of the common tuna, as any other species of tuna;  is often carried out in the same places where then the females come after a time to release their eggs.  Even, if this entails a long return journey  to the place they consider as home.

There is no distinction in terms of males and females, both alike can produce the same amount of sperm and eggs among them;  which give them the possibility to reproduce at the same time.

The female has the ability to produce at least 10 million eggs,  that the male fertilize two or three days later. .

The larvae that are deposited in  the water currents , face a big risk,  because they are considered as food for other fish and birds.  In spite of the significant amount of eggs that the female can produce,  few of them  manage to survive and become in adults common tuna.

These calves can weigh about 80 kg  and can move away from the area where they grew , grouped with  others fish species.  This routine varies , according to their sizes.

Now, let´s keep learning about this matter

Habitat of the Common Tuna

The common tunas  commonly develop in mild waters, from the North Atlantic, crossing the Mediterranean Sea and reaching the Mexican Coast.

The temperate waters are very useful for these fish, since like other species of tunas and some sharks,  the common tunas need to swim constantly to generate enough heat to maintain in perfect conditions all the organs of their bodies…

These  specimens    need to reach a higher body  temperature, than that of the water  where they  inhabit . It doesn’t mean that they are  warm blooded fish, but they  need to keep in good conditions  their  vital organs, while they  get adapted   to the waters  where  they pass.

These  fish swim at depths under  100 meters, since according to specialized studies, they have a better performance to capture their prey, in these locations. However, in some cases these fish  also approach to the coasts.

Common Tuna Population.

There isn´t a  precise information  about the total population of this species . However, according to some statistics that have been recorded since 1996, this population has decreased considerably since then.

The prolonged hunting of this species,  in countries such as Japan, has furthered this situation,  since the number of tons  of  red tuna that are caught,  ranges from 15,000 to 30,000  per month.

In spite of the several protective measures , that have been taken  by the foundations that preserve their habitat; the population of common tuna has decreased in such way,  that they belong now  to the red list of endangered species.

One of the solutions that has  been implemented, is to take a certain number of common tuna offspring  that are not yet in the adult stage, in order to raise them in  captivity.  This practice has allowed  to raise and maintain 15,000 fish,, and many of the conservatives seek to increase these figures over the years.  They predict that in 10 years they can triple these numbers.

The life expectancy of the tunas  in captivity , is around 5 years old. However many  specialist consider,  that  by adapting and improving their conditions, this statistic can be extended, since what is sought is that they can reach the adult stage and reproduce to,  in order to have more specimens.

The advantage of captivity for bluefin tuna hatchlings , is that they are not exposed to any type of danger, and the amount of eggs that the female expels will be approximately the same as that which survives under such conditions.

Now, we invite you to enjoy this video, to learn about techniques employed to breed these fish in captivity.


The predators of the common tuna, either naturals or humans, represent the main danger for them. Their offspring , as we mentioned before, face the biggest threats, since they are not enough developed  to fight  against natural predators.

The pollution of their  habitats,  prevents them  to go to their original locations, where they tend to return  to carry out their reproduction.

Therefore we must all become aware, to prevent these practices from continuing

Main Threats for the Common Tuna

The commercial fishing of this species, represents its main threat.

The rise of this practice has caused most of the red numbers in terms of its extinction . Its meat  is quite appreciated and  coveted in the world; which promotes its hunting, especially when it is young .

As a result, they obviously can´t reproduce  properly.  The overfishing doesn´t  only affect the common tuna, but also other species of the same family. In recent times the population of the common tuna has declined  by 80%.

Illegal fishing

According to agreements developed by  different associations, that fight to preserve this species; the  legal fishing index was set in 30,000 tons per year,  However, this measure furthered the creation of a sort of mafia.

Up to 50,000 illegal tons per year have been registered in different parts of the world.

The illegal fishing occurs in those countries  that for any reason are unable of controlling this type of mafias. Japan, the United States and China, have the lead in this regard.

The most immediate solution that the experts suggest, is to diminish the funds of the fishing fleets in order to avoid the common tuna overfishing.

The further captures most be focused , in placing some specimens in captivity,   allowing them to reproduce without any mishap either natural

Or   humans. , This practice should be applied immediately, since more and more  quantities of  common tuna are lost annually.

However, not everything is the fault of fishing, the common tuna population has also  decreased, due to the climatic situation in various seas where they often circulate,.

It is almost null the existence of  this species, in the Dead Sea , the Black Sea  and the Mediterranean.

On the other hand,  the pollution of their habitats, which is caused by several human activities; also represents a big threat for this species.

Finally, we   can´t forget  about their  natural predators, such  as sharks and orcas,  although  they are not as disturbing the factors mentioned above.

Enjoy this video to learn more about their naturals predators.

Properties Of The Common Tuna

As in the case of most marine species, the health benefits that this fish provides for the human body; represent the main reason of its disproportionate hunt.   .

Although it is said, that fish and seafood in general gives us all these benefits equally, the amounts of the nutrients contained in every species, usually  vary in significant way.

The common tuna possesses large amounts of omega- 3 Acid,  which make of this specimen the main source of this nutrient. Moreover, its various vitamins help fortify the defenses of our body.

This type of vitamins and fats;  help prevent cardiovascular diseases, and  to  maintain low levels of  cholesterol and triglycerides. They are also essential for preventing brian diseases.

It is quite recommended  to eat these fish when they are fresh, to take advantage  of all their nutrients and properties. Keep always in mind that the canned options are not always the best, since some alterations are made when they are proccesed, which decrease their vitamins and proteins content.

On the other hand,  the chemicals that are used to preserve them  can be harmful for our body.

Benefits Of The Common Tuna

The fats that are contained in the common tuna, are those of the kind  that bring the best benefits for our health. They also provide vitamins and proteins , which allow our bodies to process such fats almost immediately..

With this type of beneficial nutrients, it is possible to reduce the risks of several diseases. The consumption of this species complements several  functions performed by our body.

High contents of Omega 3 and Fats 

This type of nutrients are quite beneficial especially for preventing cardiovascular diseases, since they are useful to clean and purge veins and arteries, reducing also the triglycerides levels.

Vitamins and Minerals 

The contribution of the common fish in terms of proteins, is much higher than that of other food such as  beef , some dairy products and eggs. a A single portion of common tuna, has vitamin B (2-3-6-9-12) and vitamin E, as well as the main minerals such as magnesium and selenium.

Let´s keep learning


It lowers the levels of triglycerides and cholesterol .

Although it contains natural fats, they are not considered as harmful fats, on the contrary;  they help to prevent heart diseases. Its consumption also helps those who  already suffer from some of them, to reduce the risk of  further complications

Its meat is low in calories.

If you are dieting,  either to take care of your body or due to health complications,  the consumption of the common tuna,

Is even more beneficial.  Remember that its  meat has few fats, so it highly  improves the metabolism , which results in huge achievements in terms of weight loss.

However, it is not recommended  to abuse of its consumption; since some of the minerals that it contains, can affect people suffering from thyroid.

It improves the  brain activities.

There are still no studies that support this theory;  but there are many that suggest, that the consumption of common tuna by  older people, prevents  diseases such as Alzheimer’s,

The Omega-3 Acid, which is present in the common tuna , has excellent properties to delay by 2 o 3 years, the natural loss of the brain cells, decreasing this way the loss of memory.

Diseases prevented by  the consumption of Common Tuna.

As we have already mentioned, there are many diseases that are prevented by the consumption of common tuna.. The saturated fats, it contains  are the main reason of this fact. Following, we list the main diseases, that are prevented by the common tuna

    • Hypercholesterolemia. (excess of cholesterol)
    • Hypertriglyceridemia. (increase in total fats in the blood)
    • Hypertension. (increase in blood pressure of the body)
    • Diabetes
    • Obesity
    • Angina of chest
    • Infarctions.
    • Thrombosis
    • Cerebral infarctions.
    • Atherosclerosis.

Aspects to Considerate when consuming Common Tuna

It is not recommended to abuse in the consumptions of this species, since it also has properties that can be harmful to our health.

Since these specimens  are one of  the most long-lived predators in the world, they  accumulate during its life time,  certain amounts of  methyl mercury  that could affect our health if we abuse of them. (See our article bonito fish, for further information about methyl mercury)

The bigger and older the tuna meat we consume, the higerh its mercury levels.

Mercury is harmful for our body , if it is consumed in excess.  This metal  prevents the body’s neurological development; so it is not recommended  for pregnant women to consume it, neither  children under 5 years old.

The restrictions in the consumption of common tuna,  also apply for people who suffer of high levels of fats; even more in cases where the tuna is conserved with large amounts of salt. The specimens that are maintained in this way, promote the fluids  retention, and they can cause hypertension.

The common tuna may also contain large amounts of histamine; since its evolution after being fished, can cause unwanted allergic reactions, due to the accumulation of microorganism.

The appearance of histamine occurs when the fish is not refrigerated at a suitable temperature, which should be below 15º C degrees after being captured, to guarantee  that there are no problems in its consumption. It is recommended to refrigerate it properly,  and if it is possible to consume it immediately.

Common Tuna Economic Importance

The economic importance of  this fish, is based on all the benefits previously listed. This  results in the huge  amounts of these specimens  that are fished every year. The hunting of these specimens, whether it is done illegally or not, causes their high prices in the market.

In countries such as Japan; the consumption of  the common tuna in large quantities has caused much speculation  on its prices.

Being one of the countries, where the illegal fishing of this species is practiced;  they are commonly sold in a few thousand dollars. At the same time, the capture of the common  tunas is also carried out by companies that only seek to keep them in captivity, to increase its standard weight and thus be able to make a more profitable sale.

The tuna meat  represents a delight  for the palate of many diners, which at the same time traps the fishermen and condition them to explore their potential customers. Moreover, most of the best-known restaurants in the world are  the main buyers of this exquisiteness, paying often high prices, for having them in their menus

There are different criteria  on this regard.  The organizations that seek the marines species preservation maintain a strong position, since this is already an endangered species. As a result, the number of captures has been reduced; but there is still a lot of work to do.

On the other hand, many fishermen claim that the alarming numbers are not only the consequence of the catches;  but that there must be other natural aspects that attempt against them. So,  they refuse to significantly reduce their production

In spite of all the efforts that have been  carried out, the required results haven´t been achieved yet.

The  protective foundations suggest  to apply a strong control over the fishing markets, especially  in countries,  where the biggest portion of this practice takes place.

The appropriate channels must be taken  to ensure the equity in the economic benefits of the tuna´s market, without affecting  their exostence.  However, if these statistics keep growing ,they will cause the disappearance  of this species..

But since the fisheries laboratories are working better every day, we can still enjoy a delicious dish of this species.


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