Who are pearl mussels? Explicit and hidden from the eyes sides of river pearls. Habitats of pearl mussels.

Class: Bivalves

Class: Bivalvia, Lamellibranchia Linnaeus, 1758 = Bivalves, elasmobranchs

European pearl mussel(L.A. BELOVA, http://bio.1september.ru)

Since ancient times, people have appreciated the beauty of pearls - their smooth matte surface and soft shine. Pearls were used to decorate clothes, household utensils, frames of the most revered icons and book bindings. Especially large and regular-shaped pearls were kept in the state treasury as great valuables.

In Rus', starting from the 11th–12th centuries, patterned pearl embroidery on linen, silk, brocade, and velvet became widespread. Russian craftsmen created unique examples of pearl embroidery and jewelry with pearls. Pearls were used to embroider church items, ceremonial royal, princely, boyar and even folk clothing. For such sewing, they used mainly freshwater pearls, which were mined right there, within the Russian state.

Information about the extraction of pearl nuclei in Rus' is available, for example, in documents dating back to the 15th century. Novgorod pearls were especially valuable. its grains were strikingly beautiful. It was Novgorod pearls that Ivan III presented to the Hungarian king Matt in 1488.

In the 16th century Varzuga pearls, mined in the Varzuga River (Kola Peninsula), began to be in great demand. It was bought to decorate church utensils and clothing. The area near the city of Kem was famous for its especially abundant pearl fishery. In 1788, this city was given a coat of arms depicting a wreath of pearls on a blue field of water. Freshwater pearl mussel

European or common pearl mussel (Margaritifera margaritifera)- a freshwater bivalve mollusk, a relative of the well-known pearl barley. Its shell is dark, elongated, with a well-developed nacreous layer on the inner surface. The shell can reach 12–13 cm in length and about 5 cm in width. Inhabits European pearl mussel in fast cold streams and at one time, apparently, was widespread in rivers flowing into the Barents, White, Baltic Seas and the northern part Atlantic Ocean. “There is no country in Europe that would be rich, like Russia, in rivers and rivulets in which pearl shells are found,” wrote in the 80s. last century, Russian geologist A.A. Stukenberg1.

Back at the beginning of the twentieth century. in many rivers of the Kola Peninsula and Karelia there were many pearl mussels, which were actively hunted. However, in the future, due to overfishing and river pollution industrial waste the number of shellfish began to decline rapidly. Now this species is included in the Red Book of the Russian Federation.

In addition to our country, the European pearl mussel is found in the rivers of Finland, Sweden, the mountainous regions of Central Europe, and very rarely in Norway, the Baltic countries, Great Britain, and northern France. However, all European populations are under threat of complete destruction. Over the past 30 years, about half of them have disappeared, and most of the remaining ones have stopped reproducing.

The pearl oyster sticks to places with fast current, found near rapids, rifts and reaches with a sandy-rocky bottom, but avoids silted reaches with weak currents. The mollusk lives at a depth of 0.3 - 2.5 m, burrowing into the ground with the front end of the shell and sticking out the rear end with siphons. It feeds on unicellular algae and organic detritus, which it extracts from the water, filtering it through the gills. In suitable places, the density of shells sometimes reaches 70 pieces per square meter. And each mollusk passes through itself more than 50 liters of water per day, which makes it possible to purify it to crystal transparency.

Salmon now spawns in 33 rivers of the Kola Peninsula, but only in one – Varzuga – is it abundant. Why was Varzuga the most productive? A survey of the river showed the presence of a large population of pearl mussels - about 80 million individuals. This is now the largest population in the world - the rest number from 10 to 100 thousand individuals. According to rough estimates, pearl mussels in Varzuga deposit about 200 tons of suspended matter per day, ideally purifying the water.

There are three reasons for the extinction of the pearl mussel and the decrease in the number of salmon: excessive shellfish fishing, equally excessive salmon fishing, and river pollution. But timber is not floated down the Varzuga, there are no industrial enterprises here, and the river is difficult to access for mass poaching. It turns out that they have been preserved here optimal conditions for both salmon and pearl mussels.

But along with passive river protection, active measures are needed to restore the pearl mussel population. One way is to relocate adult individuals to rivers where pearl mussels did not previously live or where they have disappeared. However, it is necessary to take into account not only the suitability of aquatic biotopes, but also the presence of natural hosts for glochidia in them. So, in 1933, from the Zhemchuzhny stream near Kandalaksha, the pearl mussel was moved to the streams of the Pertozer basin, where salmon were not found, and acclimatization was unsuccessful.

Scientists believe that simultaneously with the settlement of sexually mature pearl mussels, it is necessary to disperse the glochidia. Artificial infection with glochidia could increase the efficiency of reproduction thousands of times. To do this, pearl mussels are collected, the shells are opened slightly, the sex and degree of maturity of the females are determined, they are marked and placed in cages before spawning begins. The resulting suspension of glochidia is introduced into the mouths of caught fish without removing them from the water. After 18 days, from 2 to 10 thousand larvae were noted in the experiments, fixed on one salmon. As already mentioned, such an infection is practically harmless to fish.

The restoration of the pearl mussel population can be combined with the resumption of freshwater pearl harvesting, which excludes the destruction of mollusks. However, this is a matter for the future, and first it is necessary to restore the numbers of pearl mussels and salmon.

But what are pearls, for the sake of which freshwater pearl mussels were so mercilessly caught for many centuries? The pearl consists of the same substance as the shell, i.e. mainly from calcium carbonate. The inner layer of the shell is mother-of-pearl, a derivative of one of the purine bases - guanine. Mother-of-pearl is formed by the thinnest layers, lying in several layers, which create interference of light rays, as a result of which the mother-of-pearl layer shines, shimmering with all the colors of the rainbow. A pearl, as is known, is formed after some foreign object, for example a grain of sand, gets into the wall of the mantle or into the mantle cavity, around which nacre begins to be deposited.

Sometimes the pearl grain grows to the inner surface of the shell. Then it does not form a round beautiful core and it can be difficult to separate it from the wall. Such pearls are called half pearls. Pearls formed on the body of the mollusk usually have the shape of a ball and are called ramped. It is these pearls that are especially highly valued. There is usually one pearl per shell. The quality of the pearl grain does not depend on the size of the shell and the beauty of its mother-of-pearl layer. Often, uneven, low-value pearls were found in beautiful and large shells...

Margaritifera margaritifera Linnaeus, 1758

Description: Large bivalve mollusk (shell length up to 160 mm). The outside of the shell is dark brown or black (yellow-green in young individuals), usually elongated, oval-quadrangular, slightly convex. The tops almost do not protrude. The shell at the crown is usually severely eroded and the periostracum is completely destroyed; the sculpture of the crown is visible only in the youngest individuals. Inside the valves, on their dorsal edge, there is a lock consisting only of cardinal anterior teeth. On the right valve, the tooth has the shape of a tall, irregular, quadrangular pyramid and is placed under the crown, slightly in front of it. The left valve has two cardinal teeth, less pronounced and separated by a shallow hollow. The ventral margin of the valve is usually straight or slightly concave. The nacreous layer is thick, white with a pinkish tint, often with green spots.

Spreading: Rivers Atlantic coast north-east USA, eastern Canada, Western Europe, the Baltics, Belarus and the forest zone of the north-west. Russia. In Russia it is known from Karelia, Murmansk, Leningrad and Arkhangelsk regions. The original range of the species apparently included bass rivers. Bely, Barents and Baltic seas. Nowadays the range has sharply decreased.

Number: In North America and Western In Europe, the number now does not exceed several million individuals. In the 20th century the number has decreased by more than 90%. The largest populations remained in Russia: in the rivers of the Murmansk region. (about 150 million individuals) and Karelia (about 42 million individuals). The density of mollusks is up to 200 specimens/m2 of the river bottom. In most rivers the density is lower (less than 12 specimens/m2). The rapid decline in the number of shellfish, and in some places their complete disappearance, is caused by poaching and industrial fishing of shellfish, deforestation, application of fertilizers, pesticides, timber rafting, water pollution from industrial wastewater, acid rain, reclamation work in riverbeds, eurofification, as well as factors that reduce the number of host fish (overfishing, construction of dams, acclimatization of other fish species, etc.). The number of mollusks and their distribution are also influenced by the degree of mineralization, the chemical composition and oxygen saturation of water, flow speed, the nature of the soil, temperature, and the presence of a sufficient density of host fish.

Security: Listed in the IUCN-96 Red List, European Red List, Annex 3 of the Berne Convention. In the Kandalaksha and Lapland reserves, in National Park"Panajärvi" is home to small stream populations of pearl mussels. At the end of the 80s. Attempts were made to re-acclimatize mollusks in some northern rivers. Russia, methods have been developed to intensify reproduction in natural reservoirs and on the basis of salmon farms. It is necessary to reduce the likelihood of eutrophication and pollution through strict control and monitoring of water quality, and the creation of protected areas in unpolluted basins. (especially important - in the last remaining large renewable populations of the rivers Varzuga and Umba on the Kola Peninsula and the Keret river in Karelia), limiting industrial and reclamation work in the habitats of pearl mussels, restoring their populations using developed methods, preventing acclimatization salmon fish, who do not serve as hosts for pearl mussels, international coordination of work in the field of research into ways to restore pearl mussel populations and environmental legislation, breeding mollusks in specialized farms.

Common pearl mussel— Margaritifera margaritifera Linnaeus, 1758

Description: Large bivalve mollusk (shell length up to 160 mm). The outside of the shell is dark brown or black (yellow-green in young individuals), usually elongated, oval-quadrangular, slightly convex. The tops almost do not protrude. The shell at the crown is usually severely eroded and the periostracum is completely destroyed; the sculpture of the crown is visible only in the youngest individuals. Inside the valves, on their dorsal edge, there is a lock consisting only of cardinal anterior teeth. On the right valve, the tooth has the shape of a tall, irregular, quadrangular pyramid and is placed under the crown, slightly in front of it. The left valve has two cardinal teeth, less pronounced and separated by a shallow hollow. The ventral margin of the valve is usually straight or slightly concave. The pearlescent layer is thick, white with a pinkish tint, often with green spots.

Spreading: Rivers of the Atlantic coast north-east. USA, eastern Canada, Western Europe, the Baltics, Belarus and the forest zone of the north-west. Russia. In Russia it is known from Karelia, Murmansk, Leningrad and Arkhangelsk regions. The original range of the species apparently included bass rivers. White, Barents and Baltic seas. Nowadays the range has sharply decreased.

Number: In the North. America and Western In Europe, the number now does not exceed several million individuals. In the 20th century the number has decreased by more than 90%. The largest populations remained in Russia: in the rivers of the Murmansk region. (about 150 million individuals) and Karelia (about 42 million individuals). The density of mollusks is up to 200 specimens/m² of the river bottom. In most rivers the density is lower (less than 12 specimens/m²). The rapid decline in the number of mollusks, and in some places their complete disappearance, is caused by poaching and industrial fishing of mollusks, deforestation, application of fertilizers, pesticides, timber rafting, water pollution from industrial effluents, acid rain, reclamation work in riverbeds, eurofification, as well as factors reducing the number of fish -owners (overfishing, dam construction, acclimatization of other fish species, etc.). The number of mollusks and their distribution are also influenced by the degree of mineralization, the chemical composition and oxygen saturation of water, flow speed, the nature of the soil, temperature, and the presence of a sufficient density of host fish.

Protection: Listed in the IUCN-96 Red List, European Red List, Appendix 3 of the Berne Convention. In the Kandalaksha and Lapland nature reserves, in the Panajarvi National Park, small stream populations of pearl mussels live. At the end of the 80s. Attempts were made to re-acclimatize mollusks in some northern rivers. Russia, methods have been developed to intensify reproduction in natural reservoirs and on the basis of salmon farms. It is necessary to reduce the likelihood of eutrophication and pollution through strict control and monitoring of water quality, and the creation of protected areas in unpolluted basins. (especially important - in the last remaining large renewable populations of the Varzuga and Umba rivers on the Kola Peninsula and the Keret river in Karelia), limiting industrial and reclamation work in the habitats of pearl mussels, restoring their populations using developed methods, preventing the acclimatization of salmon fish, not serving as hosts of pearl mussels, international coordination of work in the field of research into ways to restore pearl mussel populations and environmental legislation, breeding mollusks in specialized farms.

And where is it mined? This is definitely not a mineral or a natural stone. These are deposits inside a sea oyster or in river shells, covered with mother-of-pearl. There are freshwater and sea pearls.

How to distinguish river pearls from sea pearls, how much do jewelry made from natural pearls cost, does it have magical properties and who is it suitable for? You will learn about all this from the article.

What are natural pearls and what are they like?

Let's start with the fact that natural pearls cannot be completely identical. First of all, these are beads different colors, ranging from white pearlescent to black and even pink. Secondly, the sizes and shapes differ.

How to check naturalness? Pay attention to the quality of the surface. If these are natural pearls, then they necessarily have a rough surface, are quite heavy and cool.

Which pearls are more valuable - river and sea pearls, are there any differences or are they far-fetched? From the name it becomes clear that sea pearls are formed in the sea, in salt water. River - in mollusks from freshwater.

Unlike sea beads, river beads are more affordable. The reason is simple. The process of cultivating beads in freshwater rivers takes less time. In the mantle of mollusks, 12-20 beads are grown at once, while no more than two or three foreign bodies can be introduced into a sea oyster.

How much does a natural pearl cost on average? It all depends on the shape, size, cultivation method. The price can range from several hundred dollars to several tens of thousands.

Production in Russia yesterday and today

Once upon a time, Russian pearls became famous throughout the world. There was so much of it that there was enough for everyone, including for export. Delicate natural beads were used to decorate royal clothes and crowns, icons and kokoshniks, and the wedding dresses of noble ladies could not do without them.

Freshwater pearls, black, silver, white, and even with a greenish tint, were actively used in Russia to create designer jewelry. At that time they were:

• earrings;
• rings;
• necklace;
• bracelets;
• beads;
• brooches, etc.

The most valuable material was considered to be extracted from Karelian rivers. Pearls from this area had a unique bluish and silvery glow. It is noteworthy that a lady with any level of income could afford a bracelet or pendant with natural pearls. The jewelry of both the queen and simple fisher girls, each of which had several threads, was equally highly valued.

The uniqueness of products in Russia in the 19th century is mentioned in the description of a visit to the Nizhny Novgorod province of a German researcher. He wrote about how greatly he was amazed by the beauty of the whitish or yellow, soft blue and even black among Russian women. The higher the lady's position, the more items she wore. This made an indelible impression on the foreigner.

In those days, the mother of Russian pearls was the freshwater pearl mussel Margaritifera margaritifera. Dozens of provinces traded on pearl rivers. These are Arkhangelsk, Siberian, Yaroslavl, St. Petersburg, etc. Shellfish production was especially active in Karelia and in Kola Peninsula.

Not so often, but Margaritifera margaritifera was found in the Moscow region. In which rivers were shellfish harvested? The pearl mussel was found in the basin of the Dnieper, Amur and tributaries of the Volga. In total, there were up to 150 pearl-bearing rivers in the country, half of which were used for fishing on a large scale. A third of the production at that time came from the provinces in the northern part of the country.

Today in Russia they do not figure out which pearls are best in the country; they are mined mainly on an experimental basis in Karelia. Every year the state treasury is replenished with hundreds of pearls of the highest quality.

How are pearls mined these days? More than 25 years ago, they began to use delicate methods of influencing mollusks with partial opening of the valves, allowing them to be left alive. Near the Northern capital there is a reserve for the protection of fish of the salmon family and mollusks. In 2006, research work was carried out on its territory for the presence of margaritane. Several populations of no more than a few dozen adults were discovered.

Are there pearl mussels today in the previously “prolific” Novgorod region? So far, mollusks have been found only in one river, and the number of individuals is no more than a thousand; all of them are on the verge of extinction due to replacement by less demanding conditions. environment pearl barley.

So what is the difference between past centuries and modern times, why did the country's pearl reserves dry up? It's all about the salmon. There is too much demand for them. Pearl mussels can only exist in rivers where salmon live. After all, larvae develop on their gills.

Is there a possibility that the mining industry will be revived at its previous level?

Work is underway aimed at its revival. To do this, they are establishing the process of breeding salmon and protecting freshwater rivers suitable for the life and development of pearl mussels.

What is the difference between freshwater pearls and sea pearls?

Returning to the topic of differences, including from the photo, between sea and river pearls, let’s determine the main points:

1. Shine. Sea pearls emit a brighter glow in daylight, while river beads appear dull and almost matte in comparison.
2. Form. Freshwater pearls, just like natural stones, by the way, have irregular shape. Sea beads also rarely have ideal parameters, but still look more neat. In addition, river beads are often oval-shaped, while sea beads are predominantly round.
3. Price. Important difference. Sea pearls are always more expensive than river pearls. Why? This was mentioned above.
4. Nacre. Another significant indicator. Sea beads have a thinner coating, on average from 0.5 to 6 mm. This explains the abrasions that occur over time. Freshwater pearls are made almost entirely of mother-of-pearl, which means they last longer and require minimal care.

You can also distinguish between freshwater and sea pearls by analyzing their sizes. Freshwater specimens are usually smaller than marine specimens. Previously, cultured freshwater pearls were grown for several years, which negatively affected the quality of the coating, shape, and, of course, size. Not long ago, the growing period was extended to 6 years, which made it possible to correct the situation and achieve almost complete identity of pearls with sea pearls in shape and size.

The magical properties of freshwater pearls

People have believed in the magic of natural river pearls since the first acquaintance with them. It was believed that mother-of-pearl products would help one live happily ever after and reward the owner with strength of mind and body.

Psychics confirm the powerful energy of pearls, claiming that people of any age can wear jewelry with them with equal benefit.

Many believe in the properties of freshwater pearls to attract love; they are sincerely convinced that products with mother-of-pearl beads will help you meet your soulmate and live happily ever after with them for many years.

There are also some signs regarding freshwater pearls. It is believed that they should not be owned by people with a nomadic lifestyle, as well as families with small children.

Who is suitable for pearl jewelry?

So, who can wear freshwater pearls? Astrologers recommend wearing jewelry for representatives of the water signs of the zodiac. That is, the beads will feel most harmonious in life:

• Rakov;
• Scorpios;
• Aquarius.

Other signs (do not forget that beads are intended more for the female half of humanity) can also wear pearls, but without much hope for an energetic relationship.

The exception is black river pearls. It is recommended to be worn by strong signs Leo and Aries for peace of mind and tranquility.

How to clean pearls at home and how to store them

Natural freshwater pearls are stronger than sea pearls, but they are not stone; they are vulnerable and subject to destruction over time. To extend the life of mother-of-pearl beads, you need to follow simple rules operation, provide gentle and regular care.

For example, to maintain the shine of a pearl, you need to clean it from time to time. Under no circumstances should this be done with cleaning agents or vinegar. The latter will corrode the layers of mother-of-pearl and become certain death for decoration (some people use it to check whether pearls are real or not).

Clean products with warm soapy water and a soft cloth. Before storing in a box (kept separately), the pearls are allowed to dry and rubbed thoroughly.

How to care for pearls

How to care for pearls folk recipes? Potato starch or a teaspoon of salt diluted in a glass of water will help. They replace soap solution.

A separate box for storing pearl jewelry is not enough. For a complete set, take care of the accompanying protective fabrics. These could be:

• silk;
• atlas.

It is important that the materials are not only natural, but also unpainted. Is heat dangerous for pearls? It happens, so take care of the beads from drying out. summer time, store them next to a glass of water. And also, if you do not want to shorten the life of your pearl jewelry, never store it hanging without a case or box.

You have learned what freshwater pearls look like and how they differ from sea pearls; now you definitely won’t go wrong when purchasing products. Share the article with your friends! See you again!

Team LyubiKamni

In which the lateral teeth are reduced and the gills are not fused on the dorsal side.

The shell of the common pearl mussel is massive and thick-walled, the tops of its valves are usually eaten away. The length of the shell is usually up to 12 centimeters. The mother-of-pearl layer on the inner surface of the valves is shiny white.

Where does the pearl oyster live?

The common pearl mussel lives in small rivers in the north of Russia: in Karelia, on the Kola Peninsula, in the Arkhangelsk region, and is sometimes found in the rivers of the Valdai Upland.

The modern range of pearl mussels has been greatly reduced, since they are very demanding on the purity of water and the oxygen content in it. These shellfish have disappeared from polluted rivers wastewater cities and factories, timber rafting, died under the influence of the change chemical composition waters, swamping of many areas. Pearl mussel stocks are difficult to restore due to the slow growth of these animals. In the first year of life, pearl mussels reach 0.5 centimeters, in the fifth year - 2 centimeters, by 7-8 years - 3-4 centimeters, and in the tenth year of life - 6 centimeters, then giving an annual increase of about 1 millimeter. The largest shells of pearl oysters are 12-13 centimeters long and are about 70 years old.

freshwater pearls

Since ancient times, pearl mussels have been mined for the sake of river pearls, which are formed in the mantle cavity of these mollusks. How are pearls formed? When any foreign body, for example a grain of sand, gets between the shell valve and the adjacent mantle of the mollusk, it has an irritating effect on the tissue of the mollusk, and skin the mantle begins to secrete a hardening pearlescent substance. In fact, the same mother-of-pearl that forms the inner layer of the shell is released. A grain of sand is overgrown with mother-of-pearl on all sides, and a small pearl is obtained. The pearl grows as the mollusk grows. Since these animals grow very slowly, pearls also grow slowly: in 12 years it can grow into a pea, and reach a size of 8 millimeters in 30-40 years.

Freshwater pearls have always been highly valued. Ancient chronicles say that pearl embroidery has been known since the 10th century, but it probably existed even earlier. At the royal and patriarchal sewing courts there were special workshops where craftswomen wove precious lace and decorated clothes with pearl threads. In those days, even horse blankets were embroidered with pearls. Pearls were widely used in the clothing of wealthy women; girls wove pearl threads into their braids. For the first time, the protection of pearl mussels began under Peter I. To avoid the devastation of pearl mussel settlements, the tsar wrote a special decree prohibiting the fishing of young mollusks. Even more attention began to be paid to pearl fishing under Empress Elizabeth. The rivers where pearl mussels were caught were strictly guarded. Pearl mining was carried out at government expense. However, the state monopoly on pearls brought great losses to the treasury and was soon abolished.

Private pearl fishing began, which led to a significant reduction in the number of these very slow-growing mollusks. Currently, all species of our freshwater pearl mussels have become rare or are on the verge of extinction and are recommended for inclusion in the Red Book of the Russian Federation.

On Far East There are several species of pearl mussels living in Russia, for example, the Daurian pearl mussel, which lives in the Amur basin. The shell of this species is large (10-17 centimeters) with whitish-pink mother-of-pearl. Middendorf's pearl mussel is common in Kamchatka, its shell is no more than 8-9 centimeters long, the mother-of-pearl is whitish-pink or red (the color of salmon). The Sakhalin pearl mussel is found in mountain rivers southern Sakhalin and southern islands Kuril ridge. It has a large shell (10-12 centimeters), the mother-of-pearl layer of which is pink, red or purple. All these species are included in the Red Book of the Russian Federation.