Crustaceans (Crustacea). Crab fishing. Where, what and how to catch crabs Where does the crab live for children
About 500 species of crustaceans, including crabs, live on the coast and in the waters of the Black Sea. According to zoologists, there are a total of 18-19 species, having both unique features and common characteristics. Black Sea crabs are predominantly small in size (9-10 centimeters across the width of the shell), and only certain species have gastronomic value. Arthropods play an important role in the local ecosystem, and most of them are listed in the Red Book.
General characteristics of crabs
Crabs are called short-tailed crayfish because of their appearance and small tail, which is more noticeable in females. Their Latin name Brachyura translates to "short" and "tail", and the animal's evolution dates back 200 million years. The strong shell (exoskeleton) consists of chitin and protects the internal organs. Including gills, thanks to which they can live both in water and on land. The head, hidden in a recess in the external skeleton, is small in size, and the eyes are capable of seeing 360 degrees. Crabs use antennae as organs of touch, and with their help they are able to find food, even after losing their sight.
The arthropod moves sideways, using eight of its ten legs, which it can “shed” if necessary and grow back. The two forelimbs of crabs are claw-shaped and are used to defend against enemies, attack prey, tear food and deliver it to the mouth. It can be either plant (various algae) or animal (small mollusks, fish, invertebrates, and sometimes crustaceans). Enemies include certain species of predatory fish and shellfish. They are considered “orderlies of the sea”, since the majority are not only predators, but also scavengers.
Most crabs have dimensions measured in centimeters, but some species can grow up to 4 meters in limb span. They have nutritional value for humans due to their meat containing vitamins and microelements.
Crabs of the Russian Black Sea coast
Of the almost two dozen species of Black Sea crabs, only a few are widespread throughout the entire sea coast. The habitat of others is limited to areas, since these arthropods are sensitive to biological, climatic and environmental conditions. Five species are widely represented in Russian (and neighboring) waters (all are representatives of the Red Data Books).
Stone crab
Also known as the red rock crab, it gets its name from the color of its shell. Red-brown, it can vary in brown and olive shades, depending on the characteristics of the seabed. The claws are dark and brown, sometimes black. Usually found at depths of 5-30 meters, preferring rocky areas. It has a “personal” shelter and territory, which it protects from other arthropods. Females are prolific in reproduction, laying up to 150 thousand eggs at a time.
Stone crab
The wide shell of the stone crab is covered with small bumps and growths for additional camouflage, and for protection - with a set of spines and prickly microhairs. This is the largest Black Sea species (10 by 8 centimeters in width and length) and the strongest (large claws lift up to 30 of their body weight). Omnivorous, but loves organic matter - carrion, mollusks and invertebrates. The arthropod is quite fleshy, so it serves as an object of fishing, and the shells are used to make souvenirs.
marble crab
The second name is the spider crab (and for the inhabitants of the Crimean peninsula, “gypsies”), also named because of its appearance - the pattern of the trapezoid-shaped shell resembles marble, and the long limbs, covered with hairs, look like the legs of spiders. The color of chitin varies between blue, green and brown shades, and is decorated with light stripes. It prefers rocky areas of the bottom and a depth of no more than 10 meters; it likes to get out, especially at night, onto land (the only one of the Black Sea species), rising to heights of up to 2-3 meters.
Black Sea marble crab, female Having a small size, from 3 to 5 centimeters, it is cautious and timid, and in case of danger it strives to hide in the sea. The marbled crab eats small invertebrates and organic matter. This species of arthropod lives for about 3 years and breeds in shallow water. At the same time, females lay less than 90 thousand eggs. It has no special gastronomic value, but the shell is popular among souvenir manufacturers, which is why it often becomes a target for poachers.
Herbal crab
The second name is Mediterranean. He got his name because of his love for algae, where he often hides from danger or for hunting. This is helped by the greenish shades of the shell, with three characteristic spines, and symbiosis with a number of algae, invertebrates and arthropods that live on the external skeleton, further camouflaging the host. It eats carrion and small inhabitants of the seabed.
Grass crab, male The shape of the shell resembles a triangle, and an adult grass crab grows up to 7-8 centimeters. By nature, he is a “coward” and a “sprinter” - he himself does not trust his small claws, and runs away from danger at a speed of up to 1 meter per second. You can meet it at a depth of 40 meters. Active at night, during the day it hides in algae or sand. Sensitive to the salinity of water, preferring more “salty” water. Previously, the species was classified as a commercial species.
Swimming crab
As the name suggests, it is the only Black Sea representative that can swim. For this purpose, the hind pair of limbs, wide and flattened, is used. It also helps, if necessary, to quickly bury itself in the sand. Fishermen sometimes call the species “barbers” because it easily cuts nets once caught in them. The dimensions of the shell of light gray-sand shades do not exceed 3-4 centimeters.
Swimming crab
The swimming crab lives at shallow depths and is active mainly at night. It is omnivorous in its diet, and its ability to swim makes it a special opponent. The arthropod is not interesting to fishermen and is rarely used for souvenir crafts.
Blue crab
An alternative name is blue swimming crab. Brought by ships to Black Sea from the waters of the American continent in the mid-19th century. It is quite rare, and the population of the species is not growing, although females lay clutches of 2 million eggs each, due to their “love” for warmth and increased salinity of water.
Blue crab The edges of the shell are framed with sharp spines, the limbs are painted with bluish tints. The claws, the tips of which are reddish in “girls”, are of different sizes - the larger one is used to break hard shells, attack and defend, the smaller one helps to cut prey and send food into the mouth.
For life, blue crabs choose muddy and sandy areas of shallow water and river mouths, but are also found at depths of 30 meters. Adults reach a size of 30 centimeters and can weigh 500-900 grams. Having an aggressive nature, the species is a formidable opponent for natural enemies and representatives of “food”. Its small number does not allow it to be called the largest crab of the Black Sea, and biologists consider it a “guest”. The quantity and properties of the meat have made the arthropod a delicacy and a target for fishing.
I grew up in the era of dandies, chips and Pokemon. Now I am already a young adult, but I associate crabs exclusively with the Pokémon Krabby. It looked literally the same as its real prototype. I really don’t know if it’s normal to have such associations at my age, but the fact remains. :)
However, crabs themselves are very interesting animals, about which you can find a lot of interesting things. In this article I will talk about what do these animals eat? :)
What is the diet of crabs?
These creatures belong to order of decapod crustaceans. The oldest remains of crabs are found in layers of soil that belong to times of the Jurassic period. And it started approximately 200 million years ago. I can say with confidence that crabs lived side by side with dinosaurs, because the years coincide.
It is believed that there is just over six and a half thousand species of crabs.
The habitat of crabs is not small. In general, they are sea animals and are mainly located in shallow water areas. A huge number of coral reefs have been explored, in which countless representatives of these creatures have been found.
Now I will talk about the main issue on the agenda - crabs eat everything. This is actually true. If find shellfish then they eat them. If they get caught small fish, then they eat it. Couldn't catch anything - they'll eat it seaweed. And this could go on for a very long time. :)
What do crabs eat at home?
Lately, I have been increasingly hearing information about people getting pet crabs. :) So I'll cover a few basic principles for feeding crabs here:
- As mentioned above, crabs eat everything. That is, they receive both meat and plant foods. In this case, create them similar diet. You can give anything as a plant food: lettuce, fruits, berries, etc. And don’t forget about protein foods.
- Under no circumstances should you overfeed your friend. You need to feed him approximately once every three to four days. It's better to stick to your diet plan with 3 meals in 10 days.
- If you want to make the task easier for yourself, you can simply purchase it at your nearest pet store. food for fish. I read that it suits them quite well. :)
Crabs, short-tailed crayfish (Brachyura), a suborder of invertebrate animals of the order of decapod crustaceans.
The head is small; the eyes are stalked. The cephalothorax is wide, the width of the pectoral shield is from 2 to 20 cm, in the Japanese deep-sea crab (Macrocheira kaempferi) it is up to 60 cm. The first pair of walking legs is equipped with claws.
The abdomen is short, tucked under the cephalothorax; The abdominal limbs in males (2 pairs) are transformed into the copulatory apparatus; in females (4 pairs) they are used for bearing eggs.
They live in the seas, in fresh water bodies and on land. All crabs, except freshwater ones, breed in the sea. The development of the crab occurs with metamorphosis; The zoea larva emerges from the eggs, which turns into a larva - megalopa, and then into an adult crab. Only freshwater crabs (family Potamidae) do not have a free-swimming larva. A pursued crab is capable of breaking off its limbs with a sharp movement, in the place of which new ones grow.
Crabs feed mainly on invertebrates. Many crabs are edible and serve as commercial fish. T.n. The Kamchatka crab is not related to crabs, but to hermit crabs. Some crabs destroy commercial shellfish - oysters and mussels, and the Chinese mitten crab (Eriocheir sinensis) sometimes, entering rivers, destroys dams in which it makes burrows, and also spoils fishing nets.
More than 4 thousand species of crabs are known, in Russia there are about 50 species.
Crab calories
Crab meat is low in calories, since 100 g of such meat contains 73 kcal. Boiled crabs contain 96 kcal per 100 g, and the energy value of canned crabs is 85 kcal per 100 g. 100 g of steamed crabs contain 97 kcal. Crab meat has a large amount of proteins and saturates the body well with energy. In moderation, this product does not cause obesity.
Nutritional value per 100 grams:
Useful properties of crabs
Crab meat is a physiologically valuable food product. It is usually consumed boiled. It is valued for its high taste and for containing biologically active substances. When raw, crab meat has a gelatinous consistency and a grayish color.
Crab meat contains 80.1-82.5% moisture, 0.2-1.4% lipids, 11.6-19.2% protein, 1.2-2.2% ash. Crab meat contains more essential amino acids than fish meat. It also contains a large amount of glycogen (in Kamchatka crab - up to 2.4%). This carbohydrate gives crab meat a pleasant sweetish taste. Crab meat contains B vitamins. Compared to other food products of plant and animal origin, crab meat is distinguished by its high level of biologically active magnesium, phosphorus, and sulfur. Of the microelements, it contains a high content of copper. For this reason, crab meat is characterized by such a defect as blueing - the formation of colored copper compounds under the action of enzymes.
Edible meat is located in the limbs and abdomen. The limbs consist of armored tubes connected by joints. The bundle of muscle fibers that form the muscles of the limbs rests on chitinous plates connected to the shell in the area of the joints. Under the shell, the crab's body is covered with a red film, which is the basis for the formation of a new shell after the crab molts, if it remained in the sea.
Crabs are not only dietary, but also rich in vitamins, amino acids and microelements. This includes iodine, calcium, zinc, polyunsaturated fatty acids, antioxidants: taurine and vitamins, etc. Crabs are also useful for anemia, cardiovascular diseases and poor vision.
A number of high-quality products can be produced from crabs: canned food, boiled-frozen crab limbs, dried meat. The sale of fresh and chilled crabs should be done very quickly: at a temperature no higher than 12-15°C, crabs are stored for no more than 15 hours, and crabs sprinkled with finely crushed ice - 30-36 hours.
Dangerous properties of crabs
Crab meat must be eaten with caution, as it can be contaminated with bacteria due to the peculiar diet of these marine inhabitants. Regular excessive consumption of infected crabs can lead to severe toxic poisoning, and can also cause loss of hearing, vision, and disruption of the nervous system.
Also, crab meat is contraindicated for people who are allergic to seafood.
How to properly cook and clean crab.
And twenty varieties of them live in the Black Sea. They have quite decent sizes, unusual shape and habits. Most of them live in the shallow waters of the coastal zone, hiding in algae. Let's look at what types of crabs live in the Black Sea.
Stone crab
Stone crab is the largest Black Sea crab. He prefers to live in deeper places. Of course, it can also be found near the shore, but only in deserted and deserted places. The Black Sea crab, whose size reaches nine to ten centimeters, does not feed on carrion like other species; it is strong and aggressive in itself, so it can become an agile and fast predator at any time. In ambush, a crab can guard small fish, worms, and snails. His claws are very strong, he snaps them as well as hermit crabs, like seeds.
The Black Sea crab has a special type of muscle. At the molecular level, they are quite different from the muscles of humans and animals. An interesting fact is that the color of a crab’s shell always matches the color of the stones in which it lives. As a rule, this is a reddish-brown hue, but stone crabs that live among yellow sandstones are themselves very light. They protect their shelter in the rocks, as well as the surrounding territory, from other inhabitants. Females carry eggs under their abdomen. At one time they lay 130,000 eggs.
The habitat of this species is very large. Stone crabs not only live in the Black Sea, but also in the Mediterranean and on the Atlantic coast. Until the eighties of the twentieth century, its numbers were quite impressive. This species was even considered as an industrial species. Now its numbers have decreased significantly, it has become an endangered species.
But nevertheless, people engage in amateur fishing. During the day, stone crabs are found in the depths, and at night they come to the shallows. It is there that they are caught, blinded by the light of flashlights. The number of stone crab has decreased significantly due to deteriorating living conditions and uncontrolled fishing, because it has good taste.
Hairy crab
The Black Sea hairy crab is very similar to the stone crab, only its size is half the size. And the carapace is dark purple in color and covered on top with a thick layer of yellow bristles-hairs. The Black Sea crab prefers to live near the shore under rocks. Its diet is not very different from that of other crabs. It poses a danger to fish because it splits their strong shells like a nut.
marble crab
The shell of the marbled crab can be colored from dark brown to blue-green, and is dotted with a large number of light stripes that resemble marble. Because of its dark color and long limbs, it is sometimes called the spider crab. This is the only Black Sea crab that runs out of the water and travels along coastal rocks and stones.
At night they can climb rocks to a height of five meters, and along gentle slopes they can go five to ten meters from the water. But only when they sense danger, they take off with lightning speed and hide in the nearest crevice or throw themselves into the water.
What do Black Sea crabs eat? In addition to algae, they eat the remains of their fellows and various other organic matter. They will not disdain even scraps from the human table. Marble crabs are also rare and therefore considered an endangered species.
Herbal or Mediterranean crab
The Black Sea grass crab also lives in shallow water, but prefers abundant grassy thickets, but it can also live among stones. Its green shell reaches eight centimeters. When encountering a predator, it does not rely much on its claws, but immediately runs away. But he runs very quickly, albeit sideways. Its speed reaches up to one meter per second.
Lilac crab, or water lover
Black Sea crabs are very interesting. Among them there is another remarkable water-loving crab. It is quite slow and can be found not only in shallow water, but also at depths of up to fifteen meters. The lilac crab loves solitude very much. It can bury itself in the sand and remain there for weeks without air or food.
Swimming crab
The swimming crab is another one that likes to burrow into the ground. It is small in size, but its hind legs are slightly flattened, like shoulder blades. With their help, he throws sand on himself. In addition, crabs successfully use these unique flippers when swimming.
It should be noted that this is the only species that can swim. All other Black Sea crabs cannot do this.
Blue crab
The blue crab is the rarest species of sandy soil. It appeared in the waters of the Black Sea in the sixties of the twentieth century. And he arrived from the Mediterranean. It was brought in with ballast water by ships on the US East Coast. However, the Black Sea turned out to be too cold for them. Young crabs cannot survive at such temperatures, which is why they are extremely rare.
Invisible crab
The invisible crab is an amazing specimen. Its uniqueness is that it is almost impossible to detect among algae. The thin and long-legged creature is a true master of camouflage.
It plants tiny bushes of algae on its shell and in this form wanders around unnoticed.
crab pea
There is also a very small pea crab. As a rule, it lives among mussels, and sometimes even settles inside a shell with a live mollusk. Such crabs can also be found in shallow water in rocks, but it is extremely difficult to see them, since an adult specimen fits on a ten-kopeck coin.
Instead of an afterword
The Black Sea has become home to twenty species of crabs in those places where the shore is rocky and dense thickets of algae begin right at the water's edge. Such places are home to many inhabitants of the underwater world, including crabs. They also took a liking to sandbanks.
And the smallest representatives can be detected only if you take a bunch of algae and rinse them in a basin, only then will the pea crab show itself - the smallest representative of the family and the greatest master of camouflage.
The crab is not just a beautiful, colorful animal. The meat of this marine representative is considered one of the healthiest and most delicious. This is an exclusively protein product that is well suited for diets for those who want to reduce body weight.
And for those who don’t need it, crab meat will simply help diversify their diet. However, you should immediately draw your attention to the fact that buying such “yummy” will cost you quite a lot. Therefore, unfortunately, not everyone can afford it. But everyone can learn everything and even more about these marine inhabitants. Well, we present the most interesting facts about crabs.
1). Planet Earth has about five thousand varieties of crabs. And each of them, although completely different in appearance, the body structure remains the same for all - eight legs and two claws.
2). There are not only aquatic representatives of these animals, but also terrestrial ones. These guys are so sneaky. The weaker sex is very smart and inventive. They can "walk" very long distances just to drink water. They can quench their thirst right on the highway, despite the large number of cars and “peak traffic.” Well, drivers just have to watch these “cranks”.
3). - This is the representative of “fur and warmth” in this family. Their appearance is very unusual - their paws and claws are completely covered with “hide.” Until now, there is not a single saying from researchers about what such a “fur coat” is intended for.
4). The largest animal of the "ticks" has the cute name "". He is, in truth, of very suggestible size. His weight confidently approaches the 20 kg mark. But the claws in the “spread out” state are almost 4 m in length.
5). Did you know that crab claws, which look scary, are actually “not worth a damn.” They do not have any power and strength to fight the “enemy”.
They can win battles solely due to their “evil” appearance.
6). Did you know that every year in the Indian Ocean, Christmas Island being attacked by millions of crabs?
Crab meat is certainly considered a delicacy in the world of gourmet cooking. Pamper yourself with the prepared masterpieces and be healthy!
You will find other interesting facts about crabs on the Internet.