The Most numerous are vetvistousye, veslonogie, rakushkovye and raznonogie Crustacea. All of them are active participants of the biological processes occurring in the water environment. Eating a considerable quantity of the dead rests of plants, animal, Crustacea carry out function of biological water treating. In turn Crustacea serve as food practically for all fishes. Considering the big natural and practical value of Crustacea, last years it is acclimatised about 40 their kinds, including amfipody, mizidy, kumovye, dekapody. Works on artificial cultivation as a live forage for fishes and waterfowls - dafny, a Cyclops, artemy, bokoplavov and others are conducted. To the most widespread and widely known fishers-fans, is rachek-bokoplav or as they it still name, mormysh . Live bokoplavy everywhere - and in sea water, both in fresh, and in underground waters. Some freely float in thickness of water, the majority - are at the bottom. Rachki bury in sand, delat in a ground of a mink, build to itself small houses or settle down in vegetation.
Breed bokoplavy in a considerable quantity, they not only clear water, but also play essential and even defining role in a food of almost all fishes and waterfowls. The chemical analysis of these rachkov shows that their body depending on a kind contains to 53 percent of fibers, 25 percent of carbohydrates, 50 percent of free amino acids, to 111 percent of fat and other valuable substances. Bokoplavy serve some kind of indicators of cleanliness of water. There, where water dirty, rachkov is not present. They actively extend many physiologically important microcells on reservoir territory are an iodine, zinc, cobalt, copper, silicon, iron, strontium, lithium and others. Eat bokoplavy the diversified food: detritom, small live organisms, plants, fossils. Breed since spring till the autumn. Postpone depending on a kind, the size and age from one, two to 150 eggs. Meet also such rachki which postpone much more eggs.
Live bokoplavy one-two year though there is also other data. The sizes of adult individuals of the most widespread in Russia bokoplavov reach: males - from 12 to 15, females - from 8 to 10 mm. The density of populations on one square metre can fluctuate from 8 to 12 copies, in perfect conditions can reach even two-three and more thousand. Breed bokoplavy, at achievement of three-monthly age. For the life the female gives three generations on five-six dung, each generation with the general potential production about eight and a half thousand grammes.
Bokoplavy are subdivided into set of kinds, but, the main thing, all of them are very useful.
To Catch bokoplavov for their use as a nozzle on a hook it is possible gauze or another melkojacheistym a net, getting large sand-shell rock near coast on which waves, and also between the stones which have acquired silky seaweed, and in other places are rolled. To extract rachkov it is possible also, having lowered on a bottom where they live, a bunch of straw, a potato tops of vegetable or other juicy plants. In the winter in a day, and in the summer much faster these bunches are densely occupied rachkami which can be shaken on a laying.