Today we come to tell you about another species of shark that will surely fascinate you. Its about blue sharkIt is a type of cartilaginous fish belonging to the order Carcharhiniformes and the family Carcharhinidae. It is known by the name of tintoreraIt is one of the most hunted sharks in the world, as is the case with the mako sharkAlthough it was once one of the most abundant species in all seas and oceans, we will therefore give it the attention it deserves in this post.
find your all biology, characteristics and way of life of the blue shark.
Key features
It is a species that is not very large. Its body measures approximately... 4 meters in length in exceptional specimens. Generally, The male is between 1,80 and 2,2 m tallWhile The female grows to between 2,2 and 3,3 mIt's rare to see specimens that reach 4 meters. Their body is thin, stylized and spindle-shapedThis makes it a very agile and hydrodynamic shark. On average, common adults weigh around 2,5 m in length, although there are regional variations.
In the male, The weight ranges between 27 and 55 kilos while in females between 93 and 182 kilosHowever, in many populations the average weight of an adult is approximately around 80 kgThis marked sexual difference makes it easy to distinguish the sexes when they share a habitat. As for their color, the name gives it away: the back has a metallic indigo blue very intense that contrasts with the bright blue flanks and the belly white or light grayOne curious feature is that its coloration can change dull gray after death.
The eyes are quite large and have a nictitating membranea semi-transparent “eyelid” that descends to protect them when they attack or handle prey. conical and elongated snout It is accompanied by a remarkable adaptation of the jaw: the The upper jaw can project forward to bite effectively without needing to raise the head, something especially useful given the length of the face.
His teeth have the serrated edges to cut and better hold the prey. While the teeth of the upper arch are triangular and somewhat hookedThose on the lower ones are more narrow and straightAs with other sharks, renewal is constant: each tooth is replaced at frequent intervals, with very short cycles that keep the dentition always functional.
The pectoral fins are very long, narrow and slightly falcatemuch more developed than in most closely related species, such as the Tiger shark. Presents two dorsal fins, being the second small dorsalas is the anal fin. The caudal fin exhibits a elongated upper lobe which facilitates gliding in the open sea. A prominent feature is located on the caudal peduncle. dermal keel not very prominent on each side, associated with its pelagic lifestyle.
- Fusiform body and very hydrodynamic.
- Narrow, conical snout; protractile upper jaw.
- Large eyes with protective nictitating membrane.
- Five gill slits; the last one located above the beginning of the pectoral muscles.
- First back approximately halfway up the body; second dorsal and small anal.
- Long, falcate pectoral muscles; caudal with prolonged upper lobe.
- Serrated triangular dentition with continuous replacement.
- Dorsal color: deep blue, bright blue flanks and light belly.
Distribution and habitat
This animal is found widely distributed around the world. It appears natively in the Atlantic, Pacific and Indian Oceans, as well as in Mediterranean SeaIt prefers temperate and tropical waters, and is considered one of the most widespread pelagic sharks in the planet.
Their main habitat consists of the epipelagic and mesopelagic zones of ocean waters. It spends most of its time between the surface and the 300 meters, although it may exceed 1000 meters In occasional dives, especially in very warm waters where it descends to cooler layers. In thermal terms, it shows a preference for the range of 12-20 ºCadjusting its daily depth to maintain optimal conditions.
Although the blue shark is strictly oceanic, it is not uncommon for it to approach platform edges and slopes during their movements, and even to areas relatively close to the coast when following schools of fish. These approaches are more likely at night, when they perform vertical movements to search for food in surface layers.
Populations usually segregate by age and sexoccupying slightly different areas and depths. This segregation, combined with their high swimming ability, explains their presence across wide latitudinal gradients and their success as a cosmopolitan pelagic predator.
Behavior of the blue shark
Although the blue shark prefers to be in the deep water surfaceAt night it ventures to swim closer to the shore. It is an animal mostly solitary but with very marked migratory behaviors. When traveling long distances He doesn't always travel alone, but can do so in couples or small groupsespecially during feeding or on common migratory routes.
Is able to perform transoceanic migrations following major ocean circulation gyres. In the North Atlantic, for example, its path can describe trajectories clockwiselinking currents such as the Gulf Stream and those adjacent to both ocean shores. These routes are modulated by temperature, prey availability, and reproduction, in addition to the dynamics of the currents themselves.
Su agility and slim body They allow it to reach good cruising speeds with efficient energy consumption. long pectorals They act as stabilizing surfaces, and the elongated upper caudal lobe propels a sustained swim ideal for long distances.
Sometimes groups are observed formed according to the sex and sizeThe function of this social segregation is not known for certain, but it could be related to minimizing competitionsynchronicity of migration movements or reduction of risk of predation for youth.
Feeding and reproduction of the blue shark
Let's move on to its diet. It's a shark with predatory habitsIt feeds primarily on pelagic fish such as barracuda and cephalopod mollusksIts usual prey includes anchovies, sardines, herring, mackerel, bonito, horse mackerel, cod, grouper and squid (his favorite), in addition to sea birds occasional and, if there is a shortage, carrion of marine mammals. In their search for food they can travel long distances and often, They hunt in pairs or in small groups. to disperse and corral schools.
The documented diet encompasses dozens of species, with at least 24 cephalopods y 16 fish, a repertoire that demonstrates its trophic plasticity and the importance of the blue shark as top predator of the open sea. This versatility allows it to adjust its consumption to local availability, maintaining a key role in the balance of small and medium-sized pelagic populations.
Regarding its reproduction, we have a fish viviparous whose internal fertilization is carried out by the pterygopods (claspers) of the male. The females possess two uteruses and the litters are usually large: most commonly they have between 4 and 35 pupsalthough in some populations they have been observed higher values in large females. This reproductive potential is among the tallest among oceanic sharks.
La age of sexual maturation It usually begins between the 4 and 5 years in males and between 5 and 6 years in females, with intermediate maturity sizes that range around 1,9-2,0 m according to sex and region. Gestation lasts from 9 to 12 months and birth is synchronized with favorable times, varying seasonally depending on the hemisphere. The young are born measuring about 34-48cm and are independent from the very beginning; they retain a yolk sac residual that is reabsorbed shortly after birth.
El courtship ritual This includes bites from the male to the female between the first and second dorsal fins; the female does not receive serious harm because her skin is significantly thickerIt has been observed that some females decrease appetite shortly before giving birth, a behavior interpreted as a mechanism to avoid accidental predation of their own offspring.
Threats
As we have mentioned before, The blue shark is in the "near threatened" category. globally due to its intensive exploitation. In the Mediterranean Sea the degree of threat is greater and is considered in critical dangerHuman activities, the attacks on young people by larger predators and the accidental capture They explain the decline of many populations.
This is the most caught shark species in the world, with annual mortality estimates on the order of tens of millions of individuals. Historically, they were captured as bycatch (incidental catch) from longline fisheries targeting large pelagic species such as tuna or swordfish; however, the increase in the commercial value of their fins, meat and by-products has led to it being direct objective in numerous fleets. A large part of the landings comes from several countries with ocean longline fleets, including Spain, Portugal, Taiwan, Indonesia and Japan.
The fins of this shark are used for the fin soup, the skin for leather and the liver for oilIts meat is consumed fresh, dried, smoked or salted, and has even been diverted to the production of fish flourHowever, being at the top of the food chain, can accumulate heavy metals like mercury in high concentrations, so caution is advised when consuming it frequently. In some places, the meat of small specimens has been sold as if it were dogfish.
The international regulatory framework is progressing: the species is included in the Appendix II of CITES and appears in lists of conventions for the protection of migratory and marine species such as the Bonn Convention and the Barcelona ConventionEven so, fishing pressure remains high, so further action is required. coordinated measures management: capture limits, minimum sizes, reduction of fishing effortdevices and baits that minimize bycatch and release protocols that improve survival.
In nature, the predators Juvenile blue sharks include large sharks such as the white and the tigerand attacks by [other groups] have also been documented orcasFurthermore, they can house parasites specific ones, such as the tetraphyllid tapeworm Pelichnibothrium speciosum, which completes its cycle through intermediate hosts probably associated with deep-sea pelagic fish (e.g., opah and Alepisaurus).
Regarding interaction with people, the Incidents are infrequent And, in many coastal areas, this species exhibits a behavior evasivefleeing upon detecting human presence. Even so, like any great predator, it deserves to be treated with care. cautious and respectfulavoiding practices that attract him to crowded areas.
The main concern is the drastic reduction that populations are suffering. In the Mediterranean Sea alone, a very sharp decline has been documented since the 20th century. I hope that with this information you can learn more about the blue shark and its way of life. I hope that populations do not continue to decline due to bycatch and that they become more stable. effective conservation measures that ensure the persistence of this blue ocean icon.