Today we are going to talk about a somewhat strange species of shark. Its about basking shark. Its scientific name is Cetorhinus maximus and it is considered the second largest fish in the world. It is capable of reaching 10 meters in length and up to 4 tons in weight. It has an impressive silhouette that makes it a hunting shark and a sharp snout. It is well known to people who like the sea.
In this article, we'll tell you everything about the basking shark, from its characteristics to how it reproduces. We'll also include key facts about its filtering anatomy, its migratory habitat and state of conservation so that you have a complete and up-to-date view.
Key features
It has an ideal hydrodynamic shape although it moves slowly. Its sharp snout helps it feed by filtering the water. It usually swims with its mouth open to be able to make it round and filter the water through the gills.
They are usually seen from the shore, and tourists often ask how they can see them. They are frequently seen on the surface and are tolerant of the presence of humans. Although their appearance may be striking, It's not dangerous Not at all. If you go out on a boat inland, the shark will most likely come up to you out of curiosity, but it won't hurt you.
This behavior so kind to human beings makes it the object of indiscriminate hunting by fishermen. Size and weight This has allowed them to achieve high profitability on commercial fishing vessels. Just one shark can yield a ton of meat and 400 liters of oil. The liver is very rich in vitamins and can represent up to 25% of the total weight that the animal has.
The persecution this animal has suffered in the past has caused its populations decrease to such an extent that many current populations are protected by law in a large majority of countries.
These sharks possess the typical fusiform body of the lamniforms And, without experience, they can be mistaken for the great white shark. However, they are easily distinguished by their enormous cavernous mouth (in large specimens the diameter can exceed one meter), due to its very long gill openings almost encircling the head and with a relatively narrower trunk. Its teeth are minuscule (approx. 5–6 mm), hook-shaped; only a few rows in each jaw are functional, so their dentition is not designed to capture large prey.
Another distinctive feature is its large caudal peduncle with lateral keels and a broad caudal fin. In large individuals, the dorsal fin may protrude and leave a visible wake. The skin is very rough due to the dermal denticles, which in this species serve not so much to improve hydrodynamics as to protect the body from chafing and parasites. Its coloration is variable, with shades of dark brown to black dorsally that fade into a whitish-gray ventral, and may show marks or scars from encounters with lampreys or other organisms.
The basking shark's liver can account for between 20% and 25% of their body weight and it runs through much of the abdominal cavity. This contributes to the buoyancy and Energy storage during their migrations. In females, it has been observed that only the right ovary It appears to be fully functional, a unique biological trait among sharks.
Habitat and area of distribution
The basking shark can be found in pelagic zones, so it is frequently seen in coastal areas. Its distribution range is very wide, practically worldwide, from the polar regions to tropical oceans. They have the ability to adapt to different environments.
They can be seen on the surfaces of the continental shelves. Although they prefer cold waterThey typically live in areas with temperatures between 8 and 14 degrees Celsius, although populations are found in wider ranges (around 6–16°C) depending on the region. They are commonly seen in coastal areas and frequently reach bays and ports.
They feed in large concentrations of plankton in shallower waters. They are most often seen swimming near the surface. This type of shark has migratory patterns; it is capable of traveling thousands of kilometers in the ocean, following seasonal changes and the availability of zooplankton. They are especially attracted to ocean fronts, capes and islands where upwellings and concentrations of plankton occur.
In winter they spend long periods near the seabed to look for food, since there is little else on the surface. It is capable of descending to hundreds or thousands of meters deep and feed on deep-sea plankton. Contrary to what was believed in the past, it does not "hibernate": It remains active throughout the yearalternating between surface and abyssal layers.
Basking shark feeding
Although their size and seemingly terrifying appearance might suggest they eat other animals like seals and other fish, this is not the case. Despite their fearsome looks, their favorite food is... zooplanktonwhich includes small invertebrates and larvae, as well as eggs and, occasionally, very small fishThey are aquatic creatures and poor swimmers, so they are easily captured.
As surface zooplankton becomes scarcer in winter, basking sharks must migrate to deeper waters to find food or travel thousands of kilometers to find it. They usually swim slowly. no more than 2 knotswith its mouth wide open as the current of water passes through its gills.
His method is an example of passive filtration or “ram feeding”: water enters through the mouth and exits through the gill slits without the shark sucking in its own juices. This distinguishes it from the whale shark and the megamouth shark, which can perform this function. active suctionEven so, it possesses large olfactory bulbs that help it orient itself towards areas with a higher concentration of plankton.
To separate plankton from the water, it uses structures called gill rakers (gill rakers), long, thin "rakes" arranged on the gill arches. On each arch there can be on the order of 1.000 to 1.300 gill rakers about 10–15 cm in lengthwhich act as a sieve. Scientific estimates place their filtering capacity at very high volumes: from thousands of tons of water per hour (around 2.000 tons) up to the equivalent of volume of an Olympic swimming pool per hourdepending on the context and the size of the specimen.
It periodically closes its mouth to swallow the filtered mass; its stomach can accumulate remarkable amounts of food, even hundreds of kilos During times of great abundance, the gill rakers are renewed periodically. They tend to get lost in the colder months. They regenerate in spring when surface plankton proliferates again, although not all individuals follow this pattern identically.
Reproduction
These animals reach sexual maturity when they reach approximately ten years of age, although population studies suggest a wide range of 6 and 13 years between (at lengths close to 4,5–6 m). Before this time, they do not attempt to reproduce because their reproductive organs are not yet mature enough to produce offspring. The type of reproduction they have is ovoviviparous (aplacental viviparity). This means that, although the young hatch from eggs, they do so from inside the mother's womb. These eggs develop inside the female until the embryos are fully formed.
Sharks' preferred breeding season is at the beginning of summer, lasting for a period of time. gestation of a year. At this time, the ecosystem is neither favorable nor conducive to raising their young. Therefore, they are able to extend the gestation period. until the year passes...and even approaching cycles of 2–3 years according to some estimates. This flexibility gives them an advantage in synchronizing birth with periods of greater success for their offspring.
Females appear to have reproductive intervals spaced (2–4 years)The size at birth is remarkable: the young reach 1,5–2 m in length and they already have their mouths open while swimming, like miniature adults. The exact number of pups per litter is little known; one case has been documented with six embryosInside the uterus, fetuses can feed on unfertilized eggs (oophagy). In this species, as noted, the right ovary It is the one that is usually functional.
This slow reproductive cycle, with relatively small litters and long gestation times, makes the species highly vulnerable to overexploitationMany individuals are considered to be able to live for several decades, and females take longer to mature than males, which further reduces the population's capacity for recovery.
Basking shark behavior
Regarding the behavior of this animal, we can say that it loves to swim in areas close to the surface of the coast due to the fact that it is where there are more nutrients and more amount of zooplankton it can ingest. The temperature at which both the water and the outside are is a condition whether it can stay on the surface longer or has to migrate to the depths.
It is a fairly sociable animal that tends to create groups of up to 100 copies And they don't harm humans. They are capable of visual communication with their companions simply by moving their eyes from side to side. This helps them detect predators, boats, etc. They have been seen aggregations by sex and behaviors in which it appears to visually inspect nearby vessels, perhaps due to confusion with other members of its species.
Despite the basking shark being large and slow, some specimens have been observed performing jumps out of the waterThe cause remains unclear; one hypothesis is that they are trying to get rid of external parasites (lampreys and others), although there is no definitive confirmation.
Its natural predators are few, but orcas and tiger sharks They may occasionally be attacked. Their thick skin and denticles contribute to their defense. During the colder months, as already mentioned, they do not become inactive. descends to great depths and it continues to feed, which disproves old ideas about a supposed hibernation.
State of conservation and relationship with people
Despite its harmless nature, the basking shark has been historically heavily exploited for their commercial use: meat for consumption and fishmeal, liver oilsskin and also the value of the fins. In some places, even derivatives such as the cartilage in traditional medicine preparations, without solid scientific evidence for several of those uses.
As a result of the rapid decline of specimens in certain areas, international trade and targeted fishing are restricted or prohibited in numerous jurisdictions. The species enjoys total protection in several countries and large areas of Atlantic and Mediterraneanwith official threat lists in different regional categories. Various regulations prohibit their capture, retention on board, and commercialization, and promote measures for their campaigns.
The growing interest in nature tourism has boosted tourism in some regions observation and photography outings with minimal impact protocols, an alternative that, when well regulated, can promote the social value of the species and generate income without harming it.
How to tell it apart from a great white shark
The confusion with the great white shark is understandable at first glance, but there are clear signs to distinguish them. The basking shark exhibits a huge mouth always open During feeding, extremely sharp teeth small ass and very long gill slits that almost encircle his head. dorsal fin In large individuals it leaves a marked trail and its swimming pace is slowThe great white shark, on the other hand, has large, serrated teeth, an active hunting behavior, and does not swim filter-feeding with its mouth open.
Measurements and size
The basking shark is one of the largest known fish, occupying the second place in size after the whale shark. It's normal to find individuals of 6–8 mwith occasional records exceeding 10 m. After periods of intense fishing, sightings of very large specimens are less frequent. In general, females are bigger than males.
Surface observation
Basking sharks feed often on or near the surfaceWith their mouths open and gills fully extended, they move at slow speed. They do not usually avoid the presence of boats, remaining indifferent and tolerant with people swimming or diving nearby, provided that distances are respected and their movement is not interfered with.
Natural curiosities
Along the history, decomposing carcasses The remains of large basking sharks have been mistaken for supposed “sea serpents” or other mysterious animals, fueling marine legends. This is because, as they decompose, the anatomy becomes deformed and it may look like another creature.
Fact sheet and quick practical information
Scientific name: Cetorhinus maximus. Family: Cetorhinidae. Order: Lamniformes. cartilaginous fish. Diet: zooplankton and small planktonic organisms. Feeding method: Passive filtration with gill rakers. Habitat: temperate to cold waters, continental shelf and slope; capable of descending to great depths. Behavior: gregarious, migratory, active all year round. Danger to humans: minimum.
Expanded original content: habits, size and protection
El basking shark The great whitetip shark (Cetorthinus maximus) is the second largest shark in the world after the whale shark. This shark feeds on swarms of plankton, swimming through the water with its large mouth wide open to filter more than 2.000 liters of water per hour through its filter-feeding rakers in search of the small crustaceans and copepods that make up the plankton. Once it has collected a sufficient amount of food, it closes its jaws and uses pressure to expel the trapped water through its gills, thus swallowing the plankton.
The basking shark It measures between 9 and 10 meters The basking shark is typically 1.5 meters long, but can sometimes reach up to 12 meters. Female basking sharks are larger than males, which average 4 to 5 meters in length. At birth, basking sharks measure about 170 cm. Their average weight is around 3.500 kilograms.
Despite their large size, they pose no threat to humans and it is possible to swim alongside a school of basking sharks because They are completely harmless.
The basking shark has migratory habits and can be observed In solitary, in small groups and sometimes in groups of more than 100 individuals together.
This shark is found in all the world's oceans, preferring temperate waters with temperatures between 8 and 14 degrees Celsius. During the warmer months in some Atlantic regions, it is one of the places in the world where it is most abundant. It is often seen in coastal waters swimming near the surface in search of plankton. The myth that it "hibernates" is unfounded. remains active and in winter it descends to deep waters to continue feeding.
The basking shark is brownish-gray with a rough, distinctive long, pointed snout and relatively small eyes for its large size. Its body is fusiform, long, and cylindrical with a large mouth. It moves very slowly, with slow, deliberate movements of no more than... 2 knots per hour. The liver of this shark is very large, reaching a quarter of its total body weight.
Its reproduction is ovoviviparous, meaning it lays eggs inside the mother until the embryo is fully developed. It can have... 2 to 6 young with a gestation period that can exceed one year, with longer cycles depending on conditions.
Overfishing, due to the basking shark's high profitability from the quantity of meat and the nearly 400 liters of oil obtained per specimen thanks to the large size of its liver, has led to its decline. close to extinction In the past, they were endangered, but today they are protected in many countries, with threat classifications in various areas (for example, in the Mediterranean) by the International Union for Conservation of Nature (IUCN). In the Spanish catalogue of threatened species, they are considered endangered in the Mediterranean and the Iberian Atlantic Ocean.
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With all of the above, the basking shark appears as a Pacific giant of the oceans: a specialized filter feeder, with a slow swimming style and a gregarious nature, that travels enormous distances following the plankton. Understanding its biology and respecting its habitats is key to ensuring its long-term survival, especially because of its low reproductive rate and its history of exploitation. Today, its responsible observation and legal protection in numerous waters around the world are the best tools to ensure that it continues to amaze future generations.