Sea urchins are all about them. Interesting about sea urchins

The history of the existence of sea urchins (lat. Echinoidea) - benthic animals belonging to an extensive class called "Echinoderms" - has more than five hundred million years. Their life cycle begins from the moment when the male throws a stream of sperm directly into the water, and the female nearby lays eggs here. Fertilized eggs go through several stages of development and after about a month they turn into young hedgehogs with all the characteristics of an adult.

Sea urchins live in almost all seas and oceans and lead a benthic life. The main condition for their comfortable existence is salty water, so you will not see them in such lightly salted seas as the Black and Caspian. The most dangerous species of poisonous sea urchins are found in the tropical waters of the Atlantic, Indian and Pacific oceans.

According to the shape of the shell, which consists of many fixed calcareous plates, sea urchins are divided into correct and irregular. As the name implies, regular hedgehogs have a round symmetrical shell, and irregular ones have a flattened one. The organs that are very important for the sea urchin are attached to the shell - needles that can move in different directions and perform several functions at once - with their help, hedgehogs move, protect themselves from predators and get food.

In some species, the needles are almost invisible - no more than two millimeters, while the needles of others are long, about thirty centimeters, sometimes poisonous. The most common colors of sea urchins are purple and pink, less often brown, green, black, white, red.

Sea urchins, like other echinoderms, have a unique hydraulic system responsible for vital functions such as breathing, touching, moving and excreting. Hundreds of cylindrical tubes (legs) with suction cups at the end pierce the shell of the sea urchin.

Filling with water, the legs stretch and attach to the nearest surface, then, due to the change in pressure, they contract again, and the animal moves. With the help of the lower legs, sea urchins burrow into the sand or cleanse the shell of food debris, and the upper ones serve as organs of touch and respiration.

The mouth of the sea urchin, located on the lower side of the body, is equipped with a special chewing apparatus called the Aristotelian Lantern. This device is equipped with five jaws at once, each of which is crowned with a strong sharp tooth that does not stop growing throughout the life of the sea urchin. Sea urchins use their unique jaws as a scraper, peeling algae from rocks, crushing prey or digging holes.

Obtaining food for sea urchins does not present any particular difficulties - these omnivores are ready to swallow not only algae, mollusks, sponges, but also their own kind - small sea urchins and sea stars. In turn, fish, birds, lobsters will not refuse to eat sea urchins.

The most important hunter for sea urchins is the sea otter. In order not to get hurt with sharp needles, the sea otter wraps the hedgehog in seaweed or breaks it with a stone right on his chest. Hiding from predators, sea urchins climb into narrow gaps between stones, increasing them to the desired depth using needles and teeth.

In total, more than 900 species of sea urchins are known. The smallest are 3 cm hedgehogs. The largest species grow up to 30 cm in diameter. The hedgehog's body is covered with special plates that “fix” the animal's body, preventing soft tissues from creeping along the bottom. Carapace sea \u200b\u200burchin so hard that not every predator can "crack" it. But even such armor is sometimes insufficient, and nature has awarded some species of sea urchins with sharp needles. They are used not only for protection, but also for the movement of the animal along the bottom. There are poisonous sea urchins, the needles of which are connected to poisonous glands. Poisonous hedgehogs live in warm tropical and subtropical zones. The thorns of poisonous sea urchins can cause severe pain, but for the most part they do not pose a threat to humans. You should beware of splinters from thorns that may remain under the skin after an injection. If they are not removed immediately, there may be health problems.

The only species potentially dangerous to humans is “ Toxopneustes pileolus"Or" sea urchin-flower ". It lives in the western Pacific Ocean.

Sea urchins are found everywhere in salt waters. They do not live in slightly salted and fresh waters. They usually settle near the surface, but some species live at depths of up to 7 km. Moreover, hedgehogs of the correct round shape (the so-called " correct sea urchins») Live on a stone bottom, on underwater rocks, in crevices of coral reefs. AND " irregular sea urchins»Prefer soft sandy bottoms.

The mouth of sea urchins is located in the lower part of the body, while the anal and genital openings extend outward in the upper part of the shell. The mouth of correct hedgehogs has a chewing apparatus, which not only participates in grinding food, but also helps the animal crawl along the bottom and even dig holes. Irregular sea urchins do not have a chewing apparatus. These hedgehogs feed on already dead organisms (the so-called detritus) and do not need to grind their food.

Outer gills are located near the mouth (usually 5 pairs). These are the main (and in most species the only) respiratory organs. Some hedgehogs can also breathe through tubal legs or needles, and then the animal may not have gills at all.

The nervous system is very simple. Animals do not have a true brain, so there is nothing to process signals from nerve endings. There is a nerve center surrounding the mouth opening. Nerve endings extend from it to the leg processes and needles. Sea urchins sense touch, detect light, and react to chemicals. In the absence of eyes (some species have only the simplest eyes), the nerve endings allow the hedgehog to remain in the correct upright position.

Adult sea urchins are well protected from predators, but when their armor is hacked, they become a real delicacy for many marine life. Crabs, lobsters, triggerfish, sea otters, eels are the most dangerous predators for sea urchins. All of them have adapted to hunt for echinoderms, overcoming their defense mechanisms.

The man also appreciated the culinary dishes of sea urchins. In Mediterranean cuisine, in South America, in Japan, they are eaten raw with lemon. The caviar of the sea urchin is very highly valued (the cost of caviar can go up to $ 450 per 1 kg.). It is used to prepare soups, sauces for fish and meat dishes, and sushi. In home saltwater aquariums, you can often find especially spectacular sea urchins, beautiful, with long black spines. Moreover, they are kept not only for their attractive appearance, sea urchins do a good job with the uncontrolled growth of plants in the aquarium, acting as a natural cleaner. In this sense, they are similar to invertebrates (shrimp, crabs, etc.).

Who is the Sea Urchin? With what and why do these strange people sitting in a gloomy corner of an expensive Japanese restaurant eat it? Why are they not talking loudly, glancing suspiciously in our direction and clearly in no hurry to share their unusual gastronomic addictions with the rest of humanity, who knows nothing about Sea Urchins?

Probably, a frequenter of fast food establishments, seeing someone eating sea urchin caviar, will immediately rank such a person among the marginal raw-food eaters, consciously striving to exterminate all sea inhabitants in especially perverse ways. Nevertheless, you will be pleasantly surprised when you realize that fresh Sea Urchin caviar is extraordinarily delicate in taste, and its milky-cool aromatic structure resembles the pulp of ripe tropical papaya.

Sea urchins are not the most common dish in Spanish cuisine, but they are quite traditional. In Spanish restaurants, you can usually order it raw or with minimal changes from the chef. However, in high-end restaurants, such as those with a Michelin star, sea urchin caviar can be served as part of the finest dishes.

Usefulness of sea urchin caviar

If you decide to order this unusual seafood dish and the hedgehog himself is still alive on the tray in front of you, and his needles are slowly moving, then you can eat a real elixir of youth and with the flesh of a sea inhabitant absorb dozens of unique nutrients, vitamins and bioactive compounds. The benefits of eating sea urchins will make themselves felt quickly: after half an hour, a slight pleasant sensation of a surge of strength will appear throughout the body, and an hour later, a clearly distinguishable physiological euphoria will surge, which can compare with the effects of a good massage, sports training or even sex.

So, having eaten a portion of sea urchin caviar on a gloomy February morning, our body will receive:

1. fat-soluble vitamins A, D, E and water-soluble vitamins C, B6, P - niacin, B2 - riboflavin, B1 - thiamine, folacin, etc.
2. biologically active substances: gomarin, carnitine, dopamine and norepinephrine, sterols, peptides, fatty acids, terpenoids, aromatic compounds and saponins.
3. protein mixtures with a sufficiently high specific activity of thymidine and thymidylate kinase enzymes.
4. bioactive suspension with the presence of two types of endodeoxyribonucleases, which are designated as Ca, Mg-dependent and acidic metal-independent DNases, respectively.
5. current pigments are carotenoids, naphthoquinones and melanin; additionally, depending on the season, lipofuscin is present.
6. the most important pigments for proper human metabolism are the carotenoids P-carotene and P-echinenone.

In other words, sea urchin caviar

• it is a powerful support for the nervous system during periods of stressful overload, moments requiring increased concentration of attention and long periods without the possibility of sleep;
• significantly activates the work of the human reproductive and circulatory systems, mysteriously strengthens the capillaries of the brain, serving as a powerful prevention of stroke and sclerosis;
• is able, with daily use, to protect us from seasonal epidemics of respiratory infections in large cities, to stabilize the function of the endocrine system;
• promotes the rapid removal from the body of toxins, drugs and heavy metals, including radioactive substances.

The benefits of eating sea urchin caviar can hardly be overestimated. The only question is whether you are ready to enjoy the absorption of such a strange substance in the indicated amount. After all, any product, in order to be positively assimilated and to bring the benefits declared by science for your body, must be accepted by your body, first of all, psychologically. And this moment, except for yourself, no one can settle!

How to eat sea urchin caviar

Those who like to eat sea urchins have about 3-4 months a year when they are edible: in Spain this is the period from December to April, since later the water will heat up and it is no longer recommended to catch sea urchins due to sanitary and taste restrictions.

Ideally, you need to eat sea urchin caviar with a dessert spoon directly from its own shell, opened by a skilled chef. Ice white wine, preferably with a fruity tint, is ideal for accompaniment to hedgehogs.

The optimal portion of fresh sea urchin caviar for eating at a time is 70-120 grams, depending on your appetite. Some Japanese restaurants in Spain serve sashimi-style sea urchin caviar, that is, raw, but completely ready to eat, sometimes flavored with savory sauces. The only difference with the usual way of enjoying a delicacy is that you don't have to extract the treat from the hedgehog yourself. An experienced chef will do it for you, but slightly deforming the “tongue” itself when serving on an exquisite plate.

Gourmet sea urchin caviar plan

Order yourself for lunch or dinner Japanese-style oysters - seasoned with Ponzu sauce, then aguilla, fried with garlic (these are sea eel fry, an expensive and rare product), the next step will be two dozen oven-baked shrimps from Palamos and finally, as the main course, a huge ice tray with a dozen live sea urchins.

The 1997 Meursault-Charmes French white wine will be an excellent drink for such a meal. This is not the cheapest option of wine, but if it doesn’t cost you more than 200 euros per bottle, do not deny yourself a little pleasure.

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Biology

The body of sea urchins is usually almost spherical, ranging in size from 2-3 to 30 cm; covered with rows of limestone plates. The plates, as a rule, are fixedly connected and form a dense carapace (shell), which prevents the hedgehog from changing shape. According to the shape of the body (and some other characteristics), sea urchins are divided into correct and wrong... In regular hedgehogs, the body shape is almost round, and they are built according to a strictly radial five-ray symmetry. Irregular hedgehogs have a flattened body shape, and the front and rear ends of the body are distinguishable. Template: Biophoto With the shell of sea urchins, needles of various lengths are movably connected (using the articular capsule with muscle fibers). The length ranges from 1-2 mm (flat hedgehogs, Echinarachniidae) up to 25-30 cm (diadem hedgehogs, Diadematidae). There is a species completely devoid of needles - toxopneustes ( Toxopneustes), whose body is dotted with pedicellaria. The needles are often used by sea urchins for locomotion, nutrition and protection. In some species, they are poisonous, as they are connected with special poisonous glands. Poisonous species (representatives of the genera Asthenosoma, Diadema) are distributed mainly in the tropical and subtropical regions of the Indian, Pacific and Atlantic oceans.

In addition to needles, pedicellaria sit on the surface of the shell of sea urchins, as well as, at the mouth opening, special organs of balance - spheridia... In some species, pedicellaria are also equipped with poisonous glands ( Toxopneustes, Sphaerechinus).

The ambulacral system is common in echinoderms. Each ambulacral leg, equipped with a suction cup, passes through the skeletal plates of the carapace with two branches (through 2 pores). The ambulacral legs of the underside serve sea urchins for locomotion and burrowing. The dorsal legs were transformed into organs of touch and respiration. In some species, the ambulacral legs, along with needles and pedicellaria, are actively involved in the process of cleaning the shell and nutrition.

The mouth of sea urchins is located in the center of the lower ( oral) sides of the body; anal and genital openings - usually in the center of the upper ( aboral) sides. In regular sea urchins, the mouth is equipped with a chewing apparatus ( aristotelian lantern), used for scraping algae from stones. The Aristotelian lantern consists of 5 compound jaws, each ending in a sharp tooth. The teeth of the Aristotelian lantern are involved not only in food processing, but also in movement (sinking into the ground), and also, presumably, in digging holes. Irregular detritus-eating sea urchins do not have a chewing apparatus.

The intestine does not have a radial structure, but is a tube extending from the oral opening in a spiral inside the body cavity. Sometimes it goes along adnexaopening into the intestine at both ends. The respiratory organs are the external cutaneous gills located near the mouth, the ambulacral system and the adnexa.

The sense organs and the nervous system are rather poorly developed. In addition to tactile ambulacral legs and spheridia, hedgehogs have primitive eyes located on the upper side of the body.

Hedgehogs are stenohaline poikilosmotic animals that are unable to maintain a more or less constant osmotic pressure of cavity; and tissue fluids when the osmotic pressure of the environment changes, and therefore do not withstand a significant change in the salinity of the habitat.

Lifestyle and nutrition

Template: Biophoto Template: Biophoto Template: Biophoto

They are widespread in oceans and seas with normal salinity at depths of up to 7 km; absent in the slightly salted Caspian, Black and partially Baltic seas. They are widespread on coral reefs and in coastal waters, often settling there in crevices and depressions of rocks. Regular sea urchins prefer rocky surfaces; wrong - soft and sandy soil.

Sea urchins are bottom crawling or burrowing animals. They move with the help of ambulacral legs and needles. According to some assumptions, with the help of the "Aristotle lantern", sea urchins drill holes in rocks, even granite and basalt ones, where they hide at low tide and from predators. Other species bury themselves in the sand or simply cover themselves with shell pieces, algae, etc.

Almost omnivorous. The diet includes algae, sponges, bryozoans, ascidians and a variety of carrion, as well as molluscs, small starfish and even other sea urchins. Purple hedgehog Sphaerechinus granularis handles mantis shrimp easily Squilla mantis... Species living on soft ground swallow sand and silt, digesting small organisms that come with them.

Sea urchins serve as food for lobsters, sea stars, fish, birds, and fur seals. The sea urchin's main natural enemy is the sea otter. Having caught a hedgehog, the sea otter either twists it in its paws for a long time (sometimes after wrapping it in seaweed) to crush the needles and then eats it or breaks the hedgehog with a stone on his own chest. The number of hedgehogs eaten by sea otters is so great that the intestines, peritoneum and even the bones of these marine mammals sometimes stain

Sea urchins are animals that belong to the class of echinoderms.

In this class, at the moment, there are more than 900 species, which are divided into two large subclasses: correct hedgehogs and incorrect ones. A regular sea urchin has a spherical body, irregular - it resembles a stretched disc.

In irregular sea urchins, a distinction is made between the front part of the body and the back. The habitat of animals is sea expanses, up to 5000 meters deep. Sea urchins are picky about the salinity of sea water. In slightly salted seas, such as the Black, Caspian, these animals are not found.

Sea urchins live at the bottom of the sea. The so-called ambulacral legs serve as a device for their movement. There are up to several hundred of them in the body of the sea urchin. Ambulacral legs are elastic and rather long processes with a suction cup at the end. With the help of such a system, thorny inhabitants of the deep sea can move along both horizontal and vertical surfaces.

The appearance of the sea urchin

The sea urchin has a spherical body, ranging in size from 6 to 12 cm. However, there are also very tiny representatives of this species. Their size does not exceed 2-3 cm.

It's hard to believe, but the sea urchin is an animal.

The largest species of these animals grow to a diameter of 36 cm. The body of sea urchins is painted in all colors of the rainbow. In some species, the manifestation of mimicry is observed - the color of the body adjusts to the color of the soil. The body shape of sea urchins cannot change, since it is covered with carapace plates. These plates are securely connected to each other and serve as excellent protection against external influences. The carapace plates are absent near the mouth and anus.

Based on the structure of the body of the sea urchin, one part of it is always located to the sea soil, the one where the mouth is. Accordingly, on the other hand, is the anus of the animal. This opposite pole of the spherical body of the sea urchin is called aboral. Between these poles, along the meridians, there are rows of ambulacral protective plates, several dozen in each row. The plates have tiny holes through which the animal pushes its legs.

The sea urchin is a spiny ball.

Each carapace plate at the aboral pole has a small eye. A larger plate is located near it. There is a reproductive cell on it. Such plates are located around the anus and are called the apical field. On the opposite side of the body of the sea urchin, next to the mouth, there are gills. The hard shell of the animal is covered with a large number of tubercles. Needles are attached to these tubercles through the articular capsule, which has very powerful muscles. Thanks to such strong muscles, sea urchins are able to turn the needles in different directions.

The thickness of the needles of the sea urchin is 1-2 mm, the length reaches 1-3 cm, and these needles are not very sharp. There are also some species in which the length of the needles ranges from 10 to 30 cm. The needles of sea urchins are multifunctional. With their help, the animal moves and defends itself when attacked by a predator. A marine inhabitant breathes with the help of gills with air dissolved in water, and the senses are very primitive. Since representatives of irregular urchins feed mainly on plankton, they have no chewing apparatus.

The sea urchin is a crawling bottom or burrowing representative of the marine fauna. In addition to ambulacral legs, the Aristotelian lantern helps the sea urchin to move along the bottom. It is available only for representatives of the group of regular hedgehogs. From the outside, the Aristotelian lantern represents the tips of 5 long teeth. This organ is very complex and is driven by strong muscles. It controls the function of the teeth. It is with the help of the Aristotle lantern that sea urchins can scrape food from the sea floor. These animals feed on various bottom vegetation and use this complex organ to grind food.

The sea urchin is a predatory animal.

The muscles that control the work of the Aristotelian lantern are incredibly strong. With their help, the sea animal moves along the bottom, literally leaning on its teeth. With the help of this amazing organ, sea urchins can dig holes in granite rocks and destroy any surfaces. In their burrows, animals escape from a variety of predators pursuing them. Representatives of the wrong group of sea urchins have to hide among the algae or bury themselves in the ground.

Sea urchin nutrition

As noted above, a group of irregular urchins feeds on plankton. Correct hedgehogs eat more varied food. They hunt molluscs, crustaceans, eat various algae, and do not disdain carrion. Sea urchins attack their smaller relatives and starfish.

Reproduction and life expectancy

Sea urchins are both male and female, meaning they are dioecious. The female sea urchin lays eggs in shallow water, and the male fertilizes it. The species of these animals living in the Antarctic regions are viviparous. Eggs develop in a special brood chamber inside the female's body.

A sea urchin born in this way leaves the mother's body fully formed. At the age of 3 years, the thorny inhabitants of the sea reach puberty.
Life expectancy in the natural environment is 12-15 years. There have been cases when sea urchins reached the age of 35 years.

Enemies of the sea urchin

With their seemingly good protection, sea urchins are food for birds, mammals and large fish. She loves to feast on meat otter sea urchins. Catching a spiky ball, the otter throws it onto the stones, thereby breaking its strong shell. Seabirds do the same for sea urchins. Large birds grab the sea urchin with their beak and rise to a great height, where they throw the prickly animal on the stones. Then, the bird pecks soft pieces from the shattered shell.

Danger to humans

Despite the danger, sea urchins are very beautiful.

Sea urchins are dangerous to humans. Some species of these animals have thin and long needles. If a person, inadvertently, steps in the water on such a hedgehog, then serious injury cannot be avoided. The fact is that a thin needle, having pierced the human body, breaks and the tip of the needle remains in the leg. Since some species of sea urchins are also poisonous, people can suffer from severe and prolonged pain. The venom of some sea urchins causes respiratory and cardiac dysfunction and muscle paralysis.

First of all, the victim should remove the fragments of the needle from the wound and treat it with an antiseptic. After providing first aid, it is necessary to deliver the victim to the nearest medical facility, where he will be provided with qualified assistance. The injured person may have breathing difficulties and heart problems. If such symptoms are observed, the victim needs to be given artificial respiration and, in some cases, heart massage. It should be remembered that the most dangerous sea urchins are found in subtropical and tropical seas.

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