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Shell thickness of Rapana venosa was investigated from ecologically different places of the Azov -Black Sea basin. In the formation of the shell thickness there are two major trends: thickening with age, and inversely proportional to the size of the thickening of even-aged individuals of the same population. Shell thickness formation was analyzed in connection with biotic and abiotic environmental factors of influence. R. venosa ontogeny is not conducive to the rapid succession newly acquired characters in local populations. The formation of a thick shell is mainly the individual response of bions to the environment. Individuals' of the same type reaction is the cause of formation of specific conchological characters of separate populations or parts thereof. Mechanical impacts (e.g. damage by breaking predators and storm waves hitting on rocks) have no significant effect on the increasing of thickness of shells. Comparative analysis of the thickness of the shell of R. venosa from areas with different salinity shows that the direct relationship between these parameters is absent. R. venosa is capable of forming its own salinity medium in the mantle cavity, which is different from the external environment. The main factor influencing the formation of a thick-walled shell is the amplitude of the temperature fluctuations in the locality.Shell thickness of R. venosa was considered as ecomorphological character in comparison with the same feature of shell-bearing mollusks from the World Ocean at different latitude zones. It is shown that high temperature gradient is one of the most important factors of forming a thick shell. The greatest show this intertidal species and ecomorphs of temperate and high latitudes, where the temperature gradients are most expressed.

The Zernov's Phyllophora Field (ZPF) is a water area in the northwestern Black Sea (NWBS) that occupied about 11 000 km 2 in the early 20 th century. Since 2008, a water area of 4025 km 2 has been given the status of a botanical sanctuary of national importance «Zernov's Phyllophora Field». The goal of the present study is to assess the species richness and quantitative development of macrozoobenthos of the ZPF and their long-term variations under the current conditions of de-eutrophication of the Black Sea basin. The work is based on the material of 43 benthos stations performed in 2010-2013 within an area of 8400 km 2 in the ZPF. In 2010-2013, a total of 162 macrozoobenthos species were identified: Polychaeta (49 species), Mollusca (39), Crustacea (43), Ascidiacea (6); the other taxa comprised 25 species. The current level of species richness of macrozoobenthos is the highest for the entire historical period of the ZPF studies. The mean abundance and wet biomass of macrozoobenthos were estimated at 2417 ± 175 individuals/m² and 283 ± 32 g/m² (without mantle cavity fluid of bivalves). Values for Polychaeta amounted to 1017 individuals/m² and 6 g/m², Mollusca -887 individuals/m² and 256 g/m², Crustacea -165 individuals/m² and 1.3 g/m², Ascidiacea -42 individuals/m² and 17 g/m². The biomass of the dominant species, the filter-feeders Mytilus galloprovincialis, reaches 73% of the total macrozoobrnthos biomass. Our research of the long-term alterations in benthic macrofauna covers the period 1957 to 2013, including the pre-crisis time of the Black Sea ecosystem (1957)(1958)(1959)(1960), its crises of the second half of the 20 th century (1979, 1984, 1991) and the modern (post-crisis) stage (2010)(2011)(2012)(2013). Based on the maps of biomass spatial distribution for all periods mentioned above, the mean values and the total stocks of macrozoobenthos within the area 8400 km 2 of the ZPF were evaluated. The long-term changes of the macrozoobenthos biomass were analysed in relation to the main factors adversely affected the bottom biocoenoses in NWBS -i.e. anthropogenic eutrophication, oxygen depletion and near-bottom hypoxia in summer, as well as the secondary siltation of the seabed due to intensive near-bottom trawling. The most critical period for the ZPF ecosystem state occurred in the late 1970s, when the mean biomass and the total stock of macrozoobenthos decreased by 7 times in comparison with the pre-crisis period. The data collected in the first decades of the 21 st century indicate the actual recovery of the mean macrozoobenthos biomass and of its total stock in the ZPF area to the level of 1957-1960, which is related to the improving of the general ecological situation in the region.Ключевые слова: Phyllophora, биомасса, запасы макрозообентоса, макрофауна бентоса, многолетняя динамика, морская особо охраняемая природная территория, численность Nature Conservation Research. Заповедная наука 2018. 3(4): 32-43

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For the first time provides photographic images, and discussed a wide range of normal and abnormal colors of gonads Rapana venosa from the Black Sea. It has been shown that some abnormal variants of gonads color are becoming the norm, at least for some contemporary populations of Crimea. The dependence of the change in color gonads with age of the rapa-whelk is shown. Attention is paid to the color variations of the digestive gland and their relationship to the color of gonads. It is assumed that specified color changes are evidence of environmentally caused of the species' form-generation in the evolution process. The species intersexuality and absence of imposex females in the R. venosa Crimean populations is discussed.