Ecology and distribution of the Amur Chebachok Pseudorasbora parva (Temminck et Schlegel, 1846) as a biologically invasive species in the delta and estuarine coast of the river Don

Aim. To analyze the results of ichthyological monitoring in order to identify the role  of an invasive fish species, Pseudorasbora parva – known in Russia as the Amur Chebachok – in the ichthyological community of the River Don estuary littoral and delta.   Material and Methods. Research work was carried out in the prodelta and estuarine  watercourses of the Don delta in the period 2007‐2017. To catch the fish, we used  bimtral, drag nets, gill nets and other fishing gear. Standard methods were applied to  process ichthyological material. A total of 902 specimens of the Amur chebachok  were examined.   Results. The general characteristics of the invasive species from watercourses of the  delta and from Taganrog Bay are given. Its role in the formation of ichthyofauna and  its relationship with native species in new habitats has been determined. Dimensionmass indicators and other biological parameters of the species are given.  Conclusion. The linear structure of the local population of the Amur chebachok consists of different size groupings corresponding to certain ages. The process of acclimatization of the Amur chebachok in the Don delta is associated with certain interactions with elements of the local biocenosis. It was proved that when there is a high  number, both in pond farms and in natural water bodies, the species is an acute food  competitor to juveniles of both farmed or local fish. Its rapid spread is due to the  high survival rate of offspring, high environmental plasticity, rapid growth, short  puberty and the migratory activity of larvae and fry

SOME CHANGES OF REPRODUCTION FISH IN PONDS WITH VIOLATED ECOLOGICAL REGIME

The main aim of the article is to study the reproduction and study of gametogenesis (ovo-and spermatogenesis) of many valuable as commercial and of yet not covered by the fishery of species of fishes for various reasons from different taxonomic groups with a different biology. The study of gametogenesis of representatives of different ecological groups (freshwater, marine) allowed not only to establish the regularities, but also reveal features of their proceeding in an ecological conditions of water bodies that have changed due to human influence, and also to note the adaptive changes and to correlate processes occurring in different levels of life

Influence of ecological and genetic factors on differentiation of populations of some breeds of sheep

Formation of genetic structure of populations of some breeds of sheep of the North Caucasus on antigenes of blood types under the influence of ecological factors of a place of cultivation and a heredity of the initial breeds used in the course of their deducing is considered. The index of genetic similarity between these populations is defined

Ontogenic changes in coloration of rare deepwater Richardson’s ray Bathyraja richardsoni (Arhynchobatidae, Rajiformes, Chondrichthyes)

The features of the coloration of the dorsal and ventral surfaces of the rare deep-sea Richardson's ray Bathyraja richardsoni (Arhynchobatidae) in the length range from 14 to 146 cm have been studied and its ontogenetic changes have been traced. New data on the coloration of embryos, immature, maturing, and sexually mature individuals are presented. It is shown that variations in the coloration of the dorsal surface are insignificant, while the coloration of the ventral surface can vary significantly. The data obtained can be used in taxonomic and population studies, in the development of keys for species identification, in the preparation of faunal overviews and field guides, to facilitate understanding the features of coloration and its changes in deep-sea animals living in permanent darkness, and to expand knowledge about certain aspects of macro- and microevolution of deep-sea skates

New species from family Gasterosteidae in ichthyofauna of the Caspian Sea basin

There is described a new genus and species - Gasterosteus Aculeatus for the Dagestan part of the Middle Caspian from the genus Gasterosteus species Aculeatus, which differs from other kinds of family Gasterosteidae by presence of three needles on the back part of the body and by some ecological features. This species is well enough described in other southern reservoirs. In comparison of external attributes of the three-needle stickle-back of the Caspian and other southern reservoirs no special differences are revealed

Materials to studying biology of duplication of mullets in conditions of the Dagestan sector of the Caspian Sea

The ecology of the reproduction of the mullets (Mugil auratus) under conditions of Daghestan part of the Middle Caspian Sea has been studied. The superiority of the Caspian mullets over the Black Sean ones has been registered on many biological and economic factors, such as a rate of growth, age of the maturation, fertility and fatness

Биоразнообразие и рыбные ресурсы прикаспийского региона России

The article is devoted to the state-of-the-art review of materials of researches on a biodiversity and biological resources of Dagestan part Pre-Caspiy. This unique area of Caspian sea consisting its high biodiversity, owing to presence of the powerful rivers (Terek, Sulak and Samur) and gulfs (Kizlyarskiy, Agrahanskiy), creating optimum modes for development sturgeon and herring, and also convenient rookeries of a seal. All these unique natural creations are subject to strong destruction from excessive anthropogenous press.For their preservation and the further development the purposeful nature protection policy with all following questions should be carried out

OBTAINING STURGEON CAVIER FROM ACIPENSER NIKOLJUKINI BESTER IN UNCONVENTIONAL TERMS

Aim. The aim is to study the technological processes of obtaining Bester caviar in the unconventional autumn-winter period.Methods. Extraction of caviar was carried out antemortem by the pillow method cutting the oviducts. The scheme of gonadotropic stimulation for all Bester females was the same: preliminary surfagon injection at the rate of 0.5 mkg/kg, while an acceptable dose of injection is 2.5 mkg per kilogram of fish weight. The object of the research was the female bester (Acipenser nikoljukini) grown in ponds at the age of 12-13 years with the polarization rate of 7-9, the caviar of which was extracted for the third time. The mass of fish and the yield of eggs were determined by the method of Pravdina I.F. The studies were performed in 4 experimental and 1 control variants.Results. We studied the possibility of extracting the caviar of the Bester females (Acipenser nikoljukini) inhabiting the ponds at the natural water temperature in the unconventional autumnwinter period. It is shown that the hybrid form of sturgeon fishes, here, the female bester, can spawn without gradual withdrawal to spawning temperature regime and without prior exposure in these conditions in contrast to the recommendations adopted in sturgeon breeding.Conclusion. We established the possibility of obtaining and producing fresh caviar of sturgeon fishes, especially when the demand increases during the pre-New Year holidays

PROTEOLYTIC ACTIVITY OF TISSUES CARP AND VOBLA UNDER THE INFLUENCE OF CADMIUM CHLORIDE

The effect of CdCI2 (0.25 mg /l) on the proteolytic enzyme activities of the carp tissue are studied. The results confirm the involvement of cathepsin D and neutral protease in the development of the organism's response to the action of cadmium ions

Theoretical and practical meaning of ecological morphophysiological research og fish reproduction in the reservoir with ecology changed conditions

Fish reproduction research showed that the change of existence conditions changes the character of sexual cell growth changes. Evident changes in the duration of protoplasmatic growth are observed as well as the asynchronism degree of sexual cells and their development rate during annual period