overestimate the value of shellfish in nature is very difficult, because they are an important link in the food chain.First of all, they serve as food for fish, crustaceans, birds and animals.At the same shellfish play an important role in biocenotic ties, and their number in the oceans up to 2.2 billion tons.
Bivalves are natural filters.When the water passes through their mantle cavity, it is cleared from the microorganisms and organic debris.Numerous experiments have shown that on average, each of them thus cleans up to 30 liters of water per day, while reducing its Contamination about 250 times.Recognizing the great importance of shellfish, many world states to ensure the protection of the environment is now taking steps to rebuild the water biocenoses.This is done by the settlement of shellfish in areas where they may become part of the biological self-purification.
great importance in human life mollusk due primarily to their use in food.The food can be mussels, oysters, scallops and many others.The fact that their meat has a lot of elements and vitamins that are absorbed by the human body quite easily.In some European countries they are even specially bred.Note that for humans important clam not limited thereto.In some varieties grow pearls decent size.In order to start their development, the mantle should be irritated by any foreign body origin.Pearl formed can be called only when it is finally formed nacre.Then pearls used to make a variety of jewelry.
should not be underestimated and industrial significance of shellfish.From the shell of gastropod species, as well as freshwater pearl mussels are made of mother of pearl products.At the same time the ink bag of squid and cuttlefish used for the production of carcass and brown sepia of the highest quality.
Despite all this, the value of shellfish is not a purely positive.There are negative aspects.In particular, some of which cause severe damage to agriculture.For example, naked slugs in search of food destroy seedlings of crops and other plants in the garden.A lot of damage is applied as snail.Some types of lung freshwater mussels act as intermediate hosts of trematodes.A number of them refers to kamenotochtsam.They take active part in the destruction of rocks.
in rivers and reservoirs of the Azov-Black Sea basin is very common this kind of as Dracena.This mollusc is considered the only freshwater species, which leads Attached lifestyle.As a rule, he settles in the pipes and all kinds of biotech plants that fail in the intensity of its reproduction.There are also types that affect facilities in ports and ship bottoms.In this case, we are talking about the ship worm.
