About hedgehogs - green and black, round and flat, edible and poisonous. Sea urchins (Arbacia lixula)
In total, more than 900 species of sea urchins are known. The smallest are 3-centimeter “hedgehogs”. The most large 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 crawl along the bottom. Carapace sea urchin so hard that not every predator can “break” it. But even such armor sometimes turns out to be insufficient, and nature has awarded some types of sea urchins with sharp spines. They are used not only for protection, but also for moving the animal along the bottom. There are poisonous sea urchins whose spines are connected to poisonous glands. live poisonous hedgehogs in warm tropical and subtropical zones. The spines of poisonous sea urchins can cause severe pain, but for the most part they do not pose a threat to humans. You should be wary of splinters from thorns that may remain under the skin after the injection. If they are not removed immediately, health problems may occur.
The only species potentially dangerous to humans is “ Toxopneustes pileolus"or "sea urchin-flower". It is native to the western Pacific Ocean.
Sea urchins are found everywhere in salt waters. In lightly salted and fresh waters they don't live. They usually settle close to the surface, but some species live at depths of up to 7 km. Moreover, hedgehogs have a regular round shape (the so-called “ correct sea urchins") live on the rocky bottom, on underwater rocks, in the crevices of coral reefs. A " irregular sea urchins"prefer a soft sandy bottom.
The mouth of sea urchins is located in the lower part of the body, and the anal and genital openings come out at the top of the shell. Mouth the right hedgehogs It 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 are already feeding dead organisms(the so-called detritus) and they do not need to grind food.
Near the mouth there are external gills (usually 5 pairs). These are the main (and in most species the only) respiratory organs. Some hedgehogs can also breathe through tube legs or spines, 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 feel touch, detect light and react to chemical influences. In the absence of eyes (some species have only simple ocelli), nerve endings allow the hedgehog to remain in the correct vertical position.
Adult sea urchins are well protected from predators, but when their armor is cracked, they become a real delicacy for many marine inhabitants. Crabs, lobsters, triggerfish, sea otters, eels are the most dangerous predators for sea urchins. All of them have adapted to hunt echinoderms, overcoming their defense mechanisms.
Man also appreciated culinary dishes made from sea urchins. In Mediterranean cuisine, in South America, and in Japan, they are eaten raw with lemon. Sea urchin caviar is highly valued (the cost of caviar can reach up to $450 per 1 kg). It is used to prepare soups, sauces for fish and meat dishes, sushi. In home marine aquariums you can often find particularly spectacular sea urchins, beautiful, with long black spines. Moreover, they are kept not only for their attractive appearance; sea urchins cope well 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.).
Sea urchins, exotic inhabitants of the underwater kingdom, are distinguished by a variety of shapes and sizes. Their color also varies - these ancient animals have perfectly adapted to their living conditions, the color has become part of camouflage or serves to attract the attention of future prey. When you see them on the ocean floor, you should not be overly curious; some species are poisonous and are quite capable of protecting themselves from potential danger.
Echinoderms
Sea urchins belong to the phylum echinoderms; along with them, this type includes other underwater animals (stars, lilies and sea cucumbers). From the point of view of biology, they are all animals, since they are included in this kingdom. They have nothing to do with fish, since fish are more developed and complex. For example, they have a brain and notochord, and most echinoderms have a virtually undeveloped nervous system. And the body holds its shape only thanks to the protective shell. And not even in all of them: in the order of leatherbacks, the connection of the armored plates is plastic. At depth they change shape, even becoming flat. And on the surface they generally flatten, almost shrivel due to loss of water.
Currently, approximately 940 species of sea urchins are known. Among them are:
- correct (real);
- incorrect.
U the right body almost perfectly round (radial five-ray symmetry), fixed armored plates ensure its constant shape. Irregular, slightly flattened. There may be differences in the structure of sea urchins. This applies to:
- presence of needles: oddly enough, in some echinoderms main feature(spines) may be absent, they are replaced by pedicellariae;
- needle lengths (from 1 mm to 30 cm);
- the size of the body itself (from 2 to 36 cm).
But what is most striking is the variety of colors in which the needles and body can be painted: black and white, almost all colors and shades, plain and multi-colored.
Interestingly, some individuals can change color like chameleons, for example, the diadem hedgehog. This ability helps to survive in the underwater kingdom.
The structure of the body (from a biological point of view) is very simple: needles are attached to the shell using an articular capsule equipped with muscle fibers, which serve both as a means of transportation and protection. On the surface there are also pedicillaria (skeletal formations resembling tweezers). They are used during feeding and when cleaning the shell. Special organs – spheridia – help maintain balance.
The mouth is located below; in representatives of the order of regular sea urchins, it is equipped with an Aristotelian lantern, a special chewing apparatus. At the top are the anal and genital openings. When talking about the structure of the body, it is necessary to mention the special water-vascular system that controls everything life cycle echinoderms. It is unique and inherent only to them. Thanks to this system, animals breathe, touch, move and eat. It also serves as a means of equalizing osmotic pressure, a method of attachment (on the surface of the shell, the tubules of the system end with a suction cup or a leg), a tool for movement and is used when digging holes.
An interesting fact: echinoderms are practically unable to maintain constant osmotic pressure. Therefore, they are highly dependent on environmental factors. A radical change in salinity and habitat is almost impossible for these animals.
And a little more about the structure of the body:
- respiration occurs through the gills;
- there are primitive ocelli on the upper side;
- sense organs and nervous system underdeveloped;
- the intestine is primitive, connecting the oral and anal openings;
- external reproduction: the female releases millions of eggs into the water, which are fertilized by male reproductive cells.
Interesting: some species living in Antarctica are viviparous. The eggs develop in a special hatching chamber, protected by the needles of the mother. And then the young, fully formed, leave their mother.
Concluding the story about the structure of echinoderms, it is worth mentioning the ability to form growth rings on the shell. From them you can determine the age of the animal. Those who have lived for 35 years can be called centenarians. Although according to recent studies scientific discoveries It turned out that sea urchins do not have an aging mechanism. They are quite capable of living at least 200 years. This message became a sensation: all functions, including reproduction and growth, remain unchanged throughout life. Even radiation does not affect them, which was proven after studying species living on the Japanese coast.
Habitats
Sea urchins prefer to settle at depths of up to 7 km. They are very sensitive to such an indicator as salinity, so you will not find them in the Black or Caspian Seas. We can say that hedgehogs have colonized almost all oceans and seas; even in the cold Adriatic waters you can find these animals. The most large populations And species diversity– in the Atlantic, Pacific and Indian Oceans, in their tropical and subtropical zones.
Most often they live on coral reefs and rocks, easily climbing steep slopes. Although there are species (mainly representatives of the order irregular) living on a soft sandy bottom. Inhabitants of reefs and rocks use natural depressions and holes as shelter. But if there are no such people, they can independently drill a hole in quite solid rock. Sand Dwellers They act simpler - when there is danger, they bury themselves in the sand. It has been repeatedly noted that shells, stones, algae or any objects under which they can hide can be used to protect themselves from waves or predators. Due to the requirements for environment can settle quite densely. Sometimes the colonies are so densely populated that the spines of their neighbors touch each other.
Nutrition
Sea urchins eat mainly algae. They scrape them off the rocks. The diet also includes sponges, ascidians, and bryozoans. They do not disdain dead organisms, and when they swallow silt and sand, they absorb the microorganisms living there.
The prey of hedgehogs from the order regular may well be mollusks, as well as their closest relatives - stars and less large individuals yours or related species. Availability oral apparatus turns vegetarians and scavengers into predators, because each of the five jaws of the oral apparatus ends with a tooth. For example, purple Sphaerechinus granularis can even cope with a mantis crab.
Despite the protection in the form of needles and pedicellariae, the animals themselves are part food chain. They are hunted by sea otters, seals, birds, fish, lobsters, and star relatives. But many people like to eat eggs underwater inhabitants. Of the millions of eggs discarded by the female, only thousands survive.
In some countries, hedgehog caviar is a delicacy. In fact, this name is not correct, we're talking about again about eggs. And the so-called “body” is not eaten either; caviar and milt, which are kept in special chambers, are used as food. It is eaten raw, fried or added to various dishes. And the prickly shell is used as fertilizer; it contains a lot of calcium and phosphorus.
Hedgehogs are dangerous or not: myths and truth
The first myth about sea urchins is that they are all poisonous. In fact, only a few species have glands with poison; most often we are talking about representatives of the genera Asthenosoma and Diadema, living in warm tropical waters. It is believed that the poison is contained only in the spines, although in some species it is found in the pedicillaries. When in danger, pedicillaria are thrown into the water. Toxins spread around the hedgehog, creating a protective “cloud” that repels the predator. According to some data, either needles or pedicillaria are poisonous.
You can die from the injection. This is another myth. Yes, injections are painful, toxins can cause dizziness, vasospasm, and severe intoxication. Over the entire period, only a few cases of death of divers from poisonous needles. But, most likely, this is the result of increased sensitivity to toxins, that is, an individual reaction. Or the result of loss of consciousness, a person may simply drown if he is not given help. If we take into account the number of poisonous individuals living in the ocean and the frequency of accidental contacts, statistics confirm that the poison itself is not dangerous to humans.
The most dangerous for humans are:
- Toxopneustes hedgehog-flower, living on southeast coast Pacific Ocean. The effect of the poison is nerve-paralytic; it is the spasm that can lead to death.
- Asthenosoma: poison provokes disorders in the nervous system.
- Black diadems: although there is no particular toxicity in the poison, the danger lies in their prevalence in the shallow waters of the beaches of popular resorts in Egypt and Thailand. You rarely see them during the day, and a careless swimmer walking along the “safe” coastal zone in the evening may well become a victim of poisonous thorns.
- Striped: when in danger, it shoots out many pedicillaria, which end in chambers with toxin.
- Centrostephanus l. Longispinus: Found in the eastern Atlantic and Mediterranean. The animal is difficult to notice due to its ability to change color depending on the lighting.
These are the most famous poisonous hedgehogs.
It’s worth dispelling another myth: if it’s not poisonous, it’s not dangerous. This is not entirely true. In addition to a very painful injection, the danger lies in the non-sterility of the needles. Not only are they difficult to pull out, but the injection site is much more disturbing than with a splinter. Exists big risk infection, which is a common phenomenon in countries with hot climates. Therefore, without special processing and medical help is indispensable even if you are “bitten” by a non-venomous individual.
What to do
First of all, swimmers and divers are advised to be careful, watch their step in shallow water, and not approach or pick up cute animals. But no one is immune from chance. Poisonous or non-venomous pedicillaria or needles (possibly just debris) lodged in the skin require immediate action.
First aid is to leave the “kill zone”. Alone or with the help of others, the victim must return to land as soon as possible. It is unknown whether there is poison, and it is difficult to predict individual reactions. Therefore, first of all you need to get out of the water.
If the needle is not deeply embedded, you should not pull it out: nothing will work, it will only get worse. You can do it yourself:
- treat the injection site with any alcohol solution for disinfection;
- pour vinegar over the fragment or citric acid(freshly squeezed lemon or lime juice will do);
- after the fragment begins to decompose under the influence of acid, hit it with a stone several times: this will cause the fragment to crumble and finally dissolve;
- Be sure to treat the affected area with an antiseptic.
There is an alternative option: instead of hitting with a stone, you can make a hot oil compress or steam in a fairly hot water affected area for half an hour. After this, the remaining needles are squeezed out of the steamed skin.
Important: if the option with heat treatment is chosen, then the remaining stages (disinfection, treatment with acid and antiseptic) should not be ignored. And one more thing: at the slightest sign of pain after removing debris, inflammation or suppuration, it is necessary to consult a doctor.
Meeting beautiful underwater urchins, of course, can be potentially dangerous. But if you don’t frighten or disturb the animals, but watch them from a distance, then you can enjoy this activity. It’s better to organize a photo hunt for them, spectacular shots are guaranteed.
It is also suitable for breeding exotic animals. In this article we will talk about the features cohabitation with an original animal - a sea urchin, a relative of starfish, sea cucumbers and lilies. You will learn what a sea urchin looks like, what it eats, how long it lives, and what problems can arise when keeping it.
Brief description and types of exotic animal
Sea urchin is an animal belonging to the class of echinoderms. It has an almost spherical body, which reaches sizes of 2-30 cm. The body is covered with plates that form a shell. There are needles on the shell, which can be of different lengths - from 1 mm to 30 cm.
There are 940 species of sea urchins in nature. The body of one of them, called Toxopneustes, is completely devoid of spines.
This animal needs needles for movement, eating food and protection from predators. There are species whose “thorns” contain poison.
The shell, in addition to needles, is also covered with pedicellaria and spheridia (near the mouth).
The ambulacral system of the animal is designed for digging shelter and locomotion (legs on the lower part of the body), touch and breathing (legs located on the back), cleaning the shell and feeding. There are suckers on the ambulacral legs.
The mouth, or, as it is more often called, “Aristotle’s lantern,” is located in the center of the lower side of the body, the opening for removing waste products is in the center of the upper side.
They vary in color. There are species that can change color like chameleons and also glow in the dark.
Did you know? The sea urchin has primitive eyes. Therefore, all parts of the body help him feel the light. The receptors are located at the ends of its ambulacral legs.
There are two types of sea urchins:
Natural range animal habitats - ocean and sea waters with normal salinity levels. They can be found at depths of up to seven kilometers. They feed on sea otters, lobsters, starfish, seals and birds.
Poisonous species live in the waters of three oceans: Indian, Atlantic, Pacific.
If you are seriously thinking about purchasing an exotic animal for your apartment, then you will naturally be interested in the question of how long sea urchins live. IN natural environment Their life expectancy is 10-15 years. The age of centenarians reaches 35 years. How long animals can live at home will depend on the quality of aquarium care and nutrition. The age of an echinoderm can be determined by the number tree rings on the shell.
Sea urchins are credited with a number of beneficial actions - in particular, the transformation carbon dioxide into calcium carbonate and water purification from radioactive substances.
Did you know? By the way a sea urchin behaves, you can determine the purity of the water in which it lives. If it is motionless and its needles are in a drooping state, then the pond is dirty.
All the pros and cons of the content
Don't rush to buy a sea urchin for your aquarium just because you like it. Before making a purchase, weigh the pros and cons. Below you will find a list of the main advantages and disadvantages of keeping such a pet.
So, why is it worth keeping a hedgehog in a marine aquarium:
- this is a beautiful and rare animal whose behavior is interesting to observe;
- it perfectly cleans its habitat and nearby objects - once you settle a hedgehog, you can be sure that where it has walked with its thorns will always be clean.
- when caring for an aquarium, you can easily run into an animal’s needle - the injection is very painful and can lead to inflammation, and removing part of the thorn remaining in the skin is impossible - you will need to wait until it comes out on its own;
- a hedgehog has a tendency to prick everything it finds in the aquarium with its needles, and an animal hung with shells, corals, and stones is not always an aesthetic spectacle;
- they can eat sponges, corals, and other animals kept in the aquarium, and thus harm its beauty;
- to omnivorous hedgehogs do not attack their beautiful roommates, they will need to be fed with meat products;
- To keep an animal you need a spacious home equipped with good light;
- these echinoderms require ideal water quality.
Important! Experienced aquarists It is not recommended for beginners and people who do not yet have sufficient experience in caring for a marine aquarium to have hedgehogs. If the desire is great, then you need to seek advice from specialists who will help avoid unwanted consequences.
Purchase price
Sea urchin can be purchased at a pet store or online at a price of 10-30 dollars per young individual. In the second case, it can be delivered to your home, like a regular product.
Selection and arrangement of an aquarium
To house a sea urchin you will need an aquarium with a volume of at least 200 liters. Some species will require a 400 liter pool. For example, the diadem sea urchin has spines that reach maximum length 20 cm - thus, its total diameter will be 40 cm. Therefore, it simply will not survive in a pool of less than 400 liters.
The smallest of the hedgehogs is the watermelon. In addition, it has short spines. Therefore for adult An aquarium with a volume of 130 liters may be sufficient.
It is important to understand that, as a rule, pet stores sell small hedgehogs. They grow as they live in the aquarium. Therefore, before purchasing a spiny invertebrate for your home, you need to find out information about its final size.
Please understand that reef aquariums are not suitable for all urchins. For example, a black long-spined hedgehog will pose a threat to its inhabitants. It is also better to place the slate in a fish aquarium.
Important! At the planning stage of arrangement and settlement marine aquarium It is necessary to study as much information as possible about the requirements of sea urchins for water and aquarium, as well as nutrition. You need to make sure that you can provide all this to the animal.
What care is needed
The most commonly kept in aquariums are the black long- and short-spined hedgehog (Black-Short Echinometra Species), the watermelon hedgehog (Mespilia globulus), the red diadem hedgehog (Diadema setosum), the echinometra lividus, and the pencil hedgehog (Pencil Urchin). .
In general, picking up spiny invertebrates is not difficult. The main thing is to know what water parameters are necessary for the species you have chosen and whether it needs special feeding or is it able to provide food for itself.
The appearance of the creature will need to be carefully observed. If it looks unhealthy or has drooping spines, you need to check the water parameters and feed it with calcium.
For safety reasons, you should not pick up your pet or play with it. If an injury occurs while cleaning the aquarium, the wound must be washed hot water and treat with disinfectants. After the injection, redness, burning and mild swelling may occur.
What to feed
Let's figure out what sea urchins eat and what you can feed them at home.
The main type of food for herbivorous spiny balls is natural fresh algae. An additional menu may include lettuce and dandelion leaves. Frozen and dry food can be purchased at a pet store.
Did you know? In some countries, sea urchin caviar and milt are a delicacy. Caviar contains 34.9% fat and 20.3% protein. And the shell is used in agriculture for fertilizer- it contains large number calcium and phosphorus.
Omnivorous hedgehogs eat their neighbors. Therefore, when trying to bite, for example, sponges or corals, crabs or shrimps, or other shellfish, you will have to feed the invertebrate with meat. In the absence of other food, animals can feed on carrion - dead fish and other marine life. They also encroach on the lives of their relatives.
Hedgehogs usually come out in search of food at night.
Compatibility with other inhabitants of the aquarium
Before you start equipping an aquarium, you need to study information about which inhabitants can coexist peacefully with each other. Because often some species begin to eat others, thereby reducing the beauty and exoticism of the glass pool. As we have already noted, hedgehogs can be herbivores and predators. And if they are not fed enough with their favorite food, then the neighboring corals and sponges will suffer.
By purchasing certain type sea creature, you need to inquire about its compatibility with other invertebrates. In any case, it will be necessary to ensure that everyone has enough food.
So, the sea urchin is a beautiful and interesting animal that can live in an aquarium. But before you get one, it is important to know the conditions in which he is used to living and the characteristics of his behavior. On the one hand, it is exotic and unusual representative echinoderms, whose movements are interesting to follow. On the other hand, this is often sea beast called "small" natural disaster", since he is famous for his love of pinning everything that gets in his way, eating his cohabitants and spoiling the beauty of the aquarium.
However, if the aquarist manages to create a balance between the inhabitants of the sea basin, the water parameters and its design, then keeping a live spiny ball will bring only one pleasure and benefit, since it will destroy all unnecessary algal fouling.
Sea urchins belong to the class of echinoderms and there are up to 940 species. They come in very different sizes, colors and appearance. Their size varies from 2 to 30 cm. The body of sea urchins is covered with calcareous plates, which are tightly connected to each other and form a shell, i.e. shell, so the sea urchin cannot change its shape. In general, sea urchins are the most different forms, and depending on this, hedgehogs are distinguished with correct and Not correct form. Regularly shaped sea urchins are always round and symmetrical, while irregularly shaped sea urchins have a clearly visible front and back of the body.
Why do sea urchins need such long and sharp spines? For movement, nutrition and protection. There are some species of sea urchins whose spines are poisonous, but in general most sea urchins are not dangerous.
If you look closely at a sea urchin, you can see a mouth and spheridia on its body, i.e. balance organs. They also have organs of breathing and touch. The mouth is located in the lower part of the body, in the center, the anus and genital opening are in the center of the upper side. Regularly shaped hedgehogs have a chewing apparatus. Sea urchins also have sharp teeth, which are not only involved in food processing, but also for movement and digging holes. Hedgehogs of irregular shape do not have a chewing apparatus; they feed on detritus (this is a substance consisting of the remains of invertebrate animals, secretions and bones of vertebrate animals, etc.).
Sea urchins like to live in seas and oceans with normal average salt content, at depths of up to 7 km. They are most common on coral reefs, close to the coast. They like to settle in rock cracks, near rocks and reefs. Regularly shaped sea urchins choose rocky surfaces to live, while irregularly shaped sea urchins choose soft sandy surfaces. Sea urchins crawl on the surface and burrow, and they move with the help of their legs. Some marine organisms hide among the spines of sea urchins, thereby protecting themselves from other sea creatures.
Who eats sea urchins? They are eaten by fish, starfish, lobsters, fur seals, sea otters and even birds.
On average, sea urchins live 10-15 years, but sometimes their age reaches 35 years. They begin to reproduce in the 3rd year of life.
Residents of the coasts Mediterranean Sea, Northern and South America, New Zealand and Japan eat sea urchins. I myself have seen more than once how Filipinos caught them and cooked them, often offering to try them. But mostly sea urchins are eaten raw, namely their caviar and milt, which tastes like salted mushrooms, according to the stories of my parents, who recently tried them raw.
Sea urchins rarely live alone; they usually unite in a 'company'.
If you step on a sea urchin and its spines remain in your leg, you need to apply lemon or lime juice to the area. The next day everything will pass. There is no point in getting needles, because... you just pick your leg and the needles will break.
This is how hedgehogs hide, only their needles are visible:
- Submission of electronic reporting to the tax office via the Internet
- Exclusion of a legal entity from the Unified State Register for false information: grounds, appeal of the decision of the Federal Tax Service on the upcoming exclusion
- What is an inn? By contacting the authorized body, you can find out
- Application for deregistration of UTII IP UTII deregistration grounds