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Predator and ecological regulator of the sea that has survived as a species for more than 400 million years.
Currently between 150 to 200 million sharks are killed per year. With the loss of diversity, uniformity increases, dependence on a few varieties of plants and animals to feed us and, above all, vulnerability to pests and diseases increases.
Some of its biological characteristics that attract attention are that this animal is practically impervious to infections (self-defense capacity), cancer and circulatory diseases.
The demand in Asia for a soup made from the fin of the shark is enormous, which has generated a worldwide trade in the fish, currently it is being fished so mercilessly that some species of shark have been reduced incredibly by 90 percent. .
If the predatory predator that occupies the cusp in the ocean is destroyed, then we interrupt the entire balance of the food chain in that sector. The balance of nature is destroyed, and then the ecological balance from beginning to end is ruined.
The oceans, which contain 90 percent of the world's living biomass and are the primary source of food for more than 3.5 billion people, are currently severely degraded.
Sharks are disappearing around the world faster than people think, with many species in danger, others practically extinct, due to three factors related to man and his activities:
· Overfishing due to the commercialization of their fins.
· The destruction of their habitat.
Accidental overfishing, for example together with tuna fishing etc.
Sharks inhabit the seas since prehistoric times even before the existence of dinosaurs, having discovered remains of an ancestor that had smooth skin and that dates back 400 million years. Although this species is one of the oldest known, little is known about it, for example, little is known about its longevity, although it is known that it has a very slow maturation process to adulthood compared to other species and that has survived at least megafauna extinctions where more than 80 percent of these have perished.
Sharks, dogfish and rays belong to the group of elasmobranchs or cartilaginous fish, because their skeleton is not made up of bones but of cartilage, Their body covered by dermal denticles, fusiform body, dorsal fin with the characteristic rudder shape, their gills form openings and not gills; In addition, they do not have a swim bladder, since the main organ that intervenes in their flotation is the liver, which is saturated with oil. In the genitourinary system, urea is produced, which stops and fixes the water through a membrane when it passes into the blood, so it does not need to ingest more. Most are carnivores; however others are planctophages and there are also herbivores. They can be oviparous, that is, they develop by depositing a number of large eggs, surrounded by a corneal pad-shaped layer that is fixed to the bottom. They can also be viviparous, in these the offspring develops within the mother, to which it is connected through a kind of placenta to obtain its food. These characteristics make them different from bony fish or teleosts. A single handful of species attack humans, most of the 350 species are harmless, some even being vegetarian.
Sharks are found in all the seas of the planet, which is why they are considered cosmopolitan, although they are mainly found in the strip between the Tropics of Cancer and that of Capricorn. In the sea, they live by swimming like pelagic animals, reaching great speeds in their movement, thanks to their spindle-shaped body and their strong tail fin; there are some that inhabit the bottom of the continental shelf and reach the slope and the abysses, such as Apristurus indicus, caught at 1200 meters in the eastern Atlantic.
Many varieties of sharks grow slowly, take a long time to mature, and are not very fertile. The white shark reaches maturity at 9 years for males and at 15 years for females. There are other species of sharks that only give a young and some, like the Sandbar shark, begin their sexual maturity at 25 years of age. As we can see, the inability of sharks to reproduce quickly does not allow them to adequately replace the population that falls prey to the fishery. Which means that they are extremely vulnerable to over-exploitation, as it takes many years for their populations to increase again. Around 36 species, among the 100 varieties that are exploited, are vulnerable, threatened or critically endangered.
The vast majority are carnivores, but due to their size and the nature of their teeth, some are more dangerous than others, on the other hand, the main food of sharks is old and sick medium-sized fish.
Considering the incredible number of sharks caught between 150 to 200 million specimens, it is necessary to reflect. Sharks are species that, like whales and dolphins, are the predators at the top of the food chain, so they have very slow reproduction rates. This makes them very sensitive to overfishing.
In Mexico, for example, until August 2002, shark and dogfish catches, both in the Atlantic and Pacific Oceans, have totaled 14,700 tons. This figure represents an estimated decrease of 12 percent over the 1997-2001 period, and 35 percent, when compared to the 1990-1996 period, when 34,000 tonnes were caught. In 1998 there were 57 boats with permits for shark fishing, this number increased to 303 in 2002. If to date the catches remain stable, it is due to the increase in fishing effort and not to the availability of the stocks.
In the last 500 years, human activity has driven 816 species of fauna and flora to extinction, according to the list of threatened species (World Conservation Union). Since 1800, 103 species have disappeared, indicating an extinction rate 50 times the natural rate.
Many species were lost even before they were discovered and with them new possibilities for agricultural cultures, industrial products or medicines to cure disease. With the loss of diversity, uniformity increases, dependence on a few varieties of plants to feed us and, above all, vulnerability to pests and diseases increases. Biodiversity is lost due to the deterioration and fragmentation of habitats, the introduction of species, the excessive exploitation of plants, animals and fish, pollution, climate change, agriculture (reduction of the varieties used, pesticides) and reforestation with fast growing monocultures.
The 1996 Red List of the International Union for Conservation of Nature (IUCN) includes 32 species of sharks and rays, the one from 2000 shows a significant increase of 95 species, increasing from 7 to 19 in number of species classified as vulnerable and from 7 to 17 species in danger of extinction.
One can cite the case of Yemen or Djibouti, where fishermen have literally emptied that area of the Red Sea of sharks because of their fishing system with floating buoys to which they hook hooks. The objective was to cut their fins to sell them to the Asian market. All over the Red Sea there has been a massacre. The same problem exists in the Galapagos and on Cocos Island with the Black Horned Hornbill which, despite the existence of national parks in the area, suffers from terrible fishing pressure.
Today the shark is a food for rich and poor. Its meat provides cheap protein to millions of subsistence fishers.
Shark catch increased when it was discovered that its liver had an oil that contained large amounts of vitamin A. Shark liver represented, during World War II, the main source of vitamin A, reaching high prices in the world. international market; This led to a considerable increase in the catch of sharks in some countries such as the United States and Australia.
The size and weight of the shark liver vary according to the species and the season of the year; in some specimens this organ represents almost a fifth of the weight of the animal, as in the tiger shark or blue shark, also considered another of the organisms that present the liver rich in oil.
The cost of obtaining and preserving the livers, as well as the process used, changes depending on the destination given to the oil; It is used to prepare vitamin A and is currently also used in the textile and tanning industries and as a lubricating oil with high resistance to friction and heat. Also, with shark liver oil, cosmetic products are being prepared that are applied to the skin to maintain and protect it; This is done with livers that contain a substance called triterpene, such as that of the black shark (Delatias licha) and the basking shark (Cetorhinus maximus).
The boom in obtaining vitamin A from the liver of this fish diminished when synthetic methods of preparation for this vitamin were discovered and the prices of shark liver plummeted, making its capture unaffordable, since of the entire animal, this viscera was the the only one that was used at that time.
Studies carried out in recent years have shown that synthetic vitamin A is more difficult to absorb and assimilate than the natural vitamin extracted from shark liver oil, in addition to the fact that the latter serves to prevent the harmful effects of nuclear radiation.
Shark fin - a key ingredient in fin soup, an oriental specialty in religious customs - is one of the most expensive seafood products in the world ($ 60 bowl of soup).
The value of the fins depends on the color and size. It is marketed in complete sets formed by the pectoral dorsal, which represent 50 percent; the first dorsal fin and sometimes the second, which give 25 percent and the lower lobe of the tail, which is the other 25 percent. The most sought-after sharks on the fin market are the hammerhead (Sphyrna mokarran), the blue (Prionace glauca), the gray (Carcharhinus mensiorrah) and the mako (Isurus oxyrinchus).
The skin of the shark is also used, those with a length greater than 1.5 meters are used, such as the nurse, whose skin is highly appreciated for its quality, although those of other large sharks are also used, such as the 4-meter common horned. the 6.5 meter tiger or the white that can measure up to 7 meters. The first product prepared with the skin of these fish was chagrin, a rough leather that was used for scraping and polishing due to the denticles. When the industry managed to eliminate these denticles, using a chemical process, the fur trade increased and with them shoes, bags, purses, etc., have been made.
The shark fishery increased in countries such as Japan, Australia, the United States, Mexico and in some regions of the world such as South Africa, Central and South America. Shark meat is also valued, only in some countries they are more rigorous with the level of mercury that accumulates their muscle mass, the allowed level is 0.5 parts per thousand, so fishermen try to catch it in waters not polluted by substances containing this metal. Another problem with meat is the high content of urea that makes it unpleasant to smell, although it can be eliminated with careful handling and with proper culinary procedures.
The fin is often amputated and the fish carcass is returned to the sea. Even Japan, considered to be the country that most used sharks, a significant part of the catch is returned to the sea, after removing the valuable fins, for not being interested or prepared to obtain the other products. Shark capture is only profitable when all the products provided by the animal are obtained, that is, skinning the animal to send its skin to the tanneries, plucking and drying the fins to market them, filleting the best meat or drying and salting it to take advantage of it cod type, use the teeth or teeth separately as decoration (in the white shark each tooth can measure 13 centimeters and each piece can be sold for 25 dollars and a complete jaw up to 5 thousand dollars), it is calculated that the average of useful teeth for trade is 150 teeth in an adult shark, obtain the liver oil to extract vitamin A and the carbohydrate called triterpene used to prepare cosmetics and with the remains, such as viscera, cartilage, etc., make flour for food for other animals. In addition to the skeleton, chondroitin is extracted, a component of cartilage, which is used in pharmacy.
In Japan, dried, salted and smoked shark meat is a traditional food; Different dishes are also prepared based on this meat, such as hoshizame: fresh pieces of the musola shark (Mustelus manazo) that are boiled and to which a paste of pickled beans is added; arsuyaki, which is a paste, is prepared with the shark's ovaries. The yaki chukuwa, the kamaboko and the hampen are ham-type sausages, very accepted in the market. The shark they use the most is the blue or yoshikirizame (Prionace glauca). The dried and salted shark meat market has increased in Mexico, Panama, Venezuela, the Caribbean countries, Somalia, Zanzibar, Indonesia, Malaysia and Thailand, etc. Different types of shark meat are found in the markets of Spain, Portugal, France, Greece and Turkey, and the United States has developed the market for canned, smoked, dried or minced meat, for the consumption of people originating from the countries in where there is a custom to eat it.
The size and weight of the sharks caught is highly variable and this causes their commercial value to change; the best meat comes from the smallest sharks, and the best skins and fins come from the largest species, whose meat is less affordable.
Some of its biological characteristics that attract attention are that this animal is practically impervious to infections (self-defense capacity), cancer and circulatory diseases. Shark cartilage has a rare feature, it does not circulate blood through it, therefore its tissue is deficient in oxygen. Studies reveal that cartilage contains a substance that inhibits the development of new blood vessels. The function of this substance in tumors is essential because it prevents the blood supply, and thus, prevents the growth of the cancerous tumor mass. Cancer tumors are generally cells with disordered growth, which feed on what the blood supply provides, which carries nutrients. If tumor cells are fed shark cartilage matter that does not provide them with oxygen, they suffocate and die, causing the cancerous tumor to stop and break down.
Currently there is an international industry dedicated to the production of dried shark cartilage powder and they make the volume of the shark cartilage market in 1996 already reach 50 million US dollars.
As a tool for curing inflammatory diseases, shark cartilage has impressive credentials as it is an important source of chondroitin sulfate and glucosamine, which share its abilities for the success of rheumatoid arthritis and osteoarthritis and many other inflammatory diseases.
As the shark has great benefits in terms of its resistance to contracting infections, the other organs of the shark are used in the preparation of natural-type drugs for the cure of diseases of a genetic or degenerative type of organs.
350 different species are known, ranging from the small Squaliolus laticaudus of no more than 20 centimeters and 200 grams, to the giant whale shark that can measure 20 meters with a weight of 15 to 20 tons. Another large shark is the tiger or blue shark (Galeocerdo cuvieri) whose body has reached 6.5 meters and is abundant in the Gulf of California.
According to their size, in some countries sharks are those that are taller than one meter and a half and dogfish those that measure less; however, this name is applied to the species Mustelus californicus, Mustelus lunulatus, also called mamon shark, and Rhizoprionodon terranovae or law dog. The baby sharks are known as dogfish.
Sharks have evolved in an environment that has few predators, so the reoccupation rate is low. As with other marine and terrestrial predators, sharks play a very important role when consuming and removing weak or sick individuals from the ecosystem, thus contributing to maintaining the health of the different prey species.
Many species of sharks need protection, but unfortunately species protection is not the end of the problem. Well, there are perhaps bigger ones, like the destruction of their habitat.
More than half of the human population lives near the oceans and depends heavily on them for their livelihoods. But, throughout history, man has neglected this magnificent habitat and continues to build ports, resorts, processing plants, industries, shipyards, and other types of industries that pollute the seas. The vast majority of sharks use and share these seas at least at one stage of their lives and consequently are directly affected by humans altering their habitat. Sharks, unfortunately, do not have the ability to adapt to these changes in their habitat and as a consequence their number is increasingly reduced. The vast majority of sharks use the areas near the beaches as breeding grounds, which obviously indicates that they need these fully stable areas and when these areas are damaged or destroyed there is a decline in their birth rate, putting them in serious danger.
Fighting for the conservation and survival of species, regardless of their beauty or size, is, neither more nor less, fighting for our present and future. Not so long ago it was thought that it was possible to save a species separately. But it's not like that. The biosphere functions as a large organism, where each part affects the whole, sometimes significantly and sometimes insignificantly. As James Lovelock said, what is fragile is not the earth, but ourselves. She just changes, sometimes more spectacularly. We are not that lucky. We occupy a niche, a function that is very interrelated with all the others in the functioning of the biosphere, which makes us extremely dependent on the rest. The myopia caused especially by urban life, makes it difficult for us to perceive this overall vision, which conditions our behavior. Fighting against the EXTINCTION OF SPECIES is not one of the many hobbies or hobbies that people usually have to occupy their free hours. IT IS A MONUMENTAL TASK THAT PURSES THE HUMAN BEING'S OWN SURVIVAL.
Shark species that were abundant 20 years ago today have practically disappeared almost completely ?????? and the culprit, be it fisherman, polluter, consumer or trophy collector ??? is MAN.