Status and prospects of ichthyofauna use of fishery Tiligul estuary

It was established that the qualitative composition of the fish fauna and conditions of living aquatic resources Tyligul estuary depend on hydrological and hydrochemical regime of the water and salinity of its waters. At present, the fish fauna of the estuary represented 37 species of fish. To increase fish production, improve quality and biodiversity of fish fauna recommended the introduction of a pond of some species of sturgeon, salmon, mullets, flounder, goby and other, for their establishment or commercial breeding

OPTIMUM, CRITICAL AND THRESHOLD VALUES FOR WATER OXYGENATION FOR MULLETS (MUGILIDAE) AND FLATFISHES (PLEURONECTIDAE) IN ONTOGENESIS

Purpose. To determine the optimum, critical, and threshold values of water oxygenation for embryos, larvae and fingerlings of mullets and flatfishes under different temperature conditions. Methodology. Oxygen consumption was studied in chronic experiments with «interrupted flow» method with automatic fixation of dissolved oxygen in water with the aid of an oxygen sensor and automatic, continuous recording of the obtained results. «Critical» (Pcrit.), and the «threshold» (Pthr.) oxygen tension in the water have been determined. Findings. Under optimum conditions, the normal embryogenesis of mullets and flatfish to the gastrulation stage, provided 90–130% oxygen saturation. The critical content was 80–85%, the threshold – 65–70% of the saturation. At the stage of «movable embryo» depending on water temperature and fish species, the optimum range of water oxygenation was within 70‒127.1%. The most tolerant to oxygen deficiency was flounder Platichthys luscus (Pcrit – 25.4–27,5; Pthr. – 20.5–22.5%), the least resistant to hypoxia was striped mullet Mugil серhalus (Pcrit. – 50–60; Pthr. – 35–40%). The limits of the critical and threshold concentration of dissolved oxygen directly depended on the temperature and salinity, at which embryogenesis occurred. An increase in water temperature and salinity resulted in an increase in critical and threshold values for oxygen tension embryos. Mullet and flatfish fingerlings in all stages of development had a high tolerance to hypoxia, which increased as they grew. They were resistant to the oversaturation of water with oxygen. The most demanding for the oxygen regime are larvae and fingerlings of striped mullet and Liza aurata. Hypoxia tolerance of Psetta maeoticus (Psetta maeoticus) and flounder at all stages of development is very high. The fingerlings of these species can endure reduction of the dissolved oxygen in water to 2.10 and 1.65 mgO2/dm3 respectively for a long time without visible effects. Originality. For the first time, we experimentally established the optimum, critical and threshold values for water oxygenation for embryos, larvae and juveniles of striped mullet, golden mullet, haarder, flounder and Black Sea turbot. Practical value. The obtained data can be used for the optimization of culture conditions and commodity cultivation of mullets and flatfishes

ICHTHYOFAUNA OF WATER BODIES OF THE NATIONAL NATURE PARK “TUZLA LAGOONS” AND ITS COMMERCIAL FISHERIES EXPLOITATION

Purpose. To study of the current species diversity of fish fauna in the water bodies included in the National Park “Tuzla lagoons”, to assess the perspectives of their commercial fisheries exploitation. Methodology. Collection of ichthyological material was performed in different seasons of 2011–2014 across the entire area of lagoons and coastal zone of the Black Sea included in the National Nature Park “Tuzla lagoons”. During commercial fish harvest, the material was collected from commercial fishing gear (gillnets, traps, hoop nets, beach seines). In fall, during the work of the fish catch-release channel, we analyzed the data describing the species composition, abundance and length-weight characteristics of fish migrating through the channel in the sea. We used the method of average representative sampling. During the closed period, ichthyologic material for the analysis was collected from the survey fishing gears. All catches were sorted by species composition. We recorded the total catch and the ratio of different species. Collection and processing of data were carried out using generally accepted methods. Findings. It 2011–2014, 72 fish species belonging to 30 families were detected in waters included in the National Nature Park “Tuzla lagoons”: 58 species in the coastal zone of the sea, 28 species in Dzhenshei and Maly Sasyk, 31 species in Tuzla lagoons. Among the fish detected in sea and freshwaters of the National Nature Park “Tuzla lagoons”, 6 species are listed in the Red Book of Ukraine, 7 are protected by Bern Convention, 4 are lusted in the Red List of the International Union for Conservation of Nature and Natural Resources, and 16 species are listed in the Red Book of the Black Sea. Before 2001, a mullet-rearing fish farm operated in Tuzla lagoons. Its fish productivity depended on the intensity and amounts of stocking which were determined by the regime of the work of lagoon–sea channels, state of natural food reserves, hydrometeorological conditions, and hydrochemical regime of water bodies. In order to optimize the ecological condition of the lagoons, to preserve their unique ecological communities, current economic status, biological diversity of biota and high fish productivity, it is necessary to foresee the construction and operation of at least two fish catch-release channels in spring and beginning of fall in the marine streamer. Originality. For the first time we carried out a study of the composition of fish fauna in water bodies included in the NPP “Tuzla lagoons”, assessed its current state and perspectives of its commercial fisheries exploitation. Practical value. The obtained data will contribute to the preservation of biological diversity in water bodies of the NPP, to the improvement of the efficiency of their commercial fisheries exploitation

Reducing organic contamination of shallow areas in brackish lagoons during rearing fish in cages in polyculture

Purpose. The development of the technology of the controlled rearing of marine fish remains one of the priority strategic trends of development of national mariculture. A study of the possibility of using polyculture for cage culture has a particular interest. Joint cultivation of several species of fish in the same cage, as practice of fish farming has demonstrated, does not have a tangible positive effect. At the same time, the use of cages of special design can provide significant additional fish products through the use of additional aquaculture objects. The ecological state of water areas, where the cages are located, is of great importance. High fish stocking density and the use of artificial feeds can serve as a source of powerful biogenic and organic pollution, which is especially important for shallow water areas with weak water exchange. The purpose of the study is to develop the methods for joint fish production in cage mariculture capable to provide high fish production and to weaken organic pollution of shallow water areas where cage farms are located. Methodology. The studies were conducted in 1999 and 2004. Cages of special design (internal 10 m3 and external 18.75 m3) installed in the brackish Shabolat Lagoon were used for rearing, steelhead trout, haarder, grass goby and round goby in polyculture. The standard aquaculture research methods were used. For express-analysis of environment hydrochemical parameters in cage location area the following devices were used: "ECOTEST-2000 T" (О2, NO2, NO3, NH4, CO2, phosphates, pH); termooksimetr "АJА-101М" (Т; О2); "pH meter-150 M); Refractometer "ATAGO-100" (salinity and water density). Findings. The results of marine fish cultivation in cages in polyculture in the shallow Shabolat lagoon are presented. It has been shown that joint cultivation of salmon, mullet and gobies in specially designed cages in shallow marine lagoons allows using artificial and natural feeds more fully and provides a high yield of commercial fish that results in significant additional products with a decrease in pollution level of the water area where the cages are installed. Originality. An original method for rearing marine fish in polyculture in specially designed cages has been developed. The perspective of culturing salmon, mullet and gobies in the polyculture has been demonstrated experimentally. The proposed technology ensures high efficiency of cage mariculture, allows getting additional production through the use of additional facilities and a reduction in the level of organic pollution in shallow water areas where cage farms are located. Practical value. The results of the study can be used to create cage mariculture farms in shallow seaside lagoons. Creating marine fish polyculture in specially designed cages will increase the efficiency of cultivation, reduce feed costs and reduce pollution in shallow water areas

Effect of the diet and growing conditions on the manifestations of cannibalism in the eastern freshwater shrimp (Macrobrachium nipponense De Haan, 1849)

Purpose. To study the effect of diet and water flow composition on the manifestations of cannibalism of shrimp Macrobrachium nipponense during rearing under controlled conditions. Methodology. The material for the work was shrimp fry with a length 2.0-3.5 cm and weight 1.5-3.0 g, caught in autumn 2016 in ponds of the lower reaches of the Dniester river. The shrimp were kept in tanks of the recirculation system with a volume of 0.3 m3. The temperature regime, light (period and intensity), and other environmental parameters were maintained in accordance with the specified parameters. Weighing was carried out on an AXISAD-50 electronic balance with an accuracy of 0.001 g. The length was measured with a ruler or with a caliper. In chronic experiments, two groups of shrimps were kept at the stocking density of 3 ind./L, temperature of 26-29°C and other equal conditions in tanks of a recirculating system. The diet of the first group consisted of animal food (bloodworm, fish, squid, snail, tubule, artemia), the second group was fed by plant feeds (cereals, vegetables, spinach, nuts, alfalfa, rice, chickpeas). Maturation of females in the second group was not observed. At the same time, cases of aggressive behavior were rare, and cannibalism was not observed, which ensured 100% survival. In the second series of experiments, shrimp were kept in fattening tanks at stocking density of 2 ind./L and a ratio ♂♂: ♀♀ - 1: 4. The diet of shrimp consisted of animal and plant feeds (1: 1). During the 30 days of the experiment, the water temperature was maintained at 26.0 ± 0.5 °C, the photoperiod was 12 hours light, 12 hours dark. Findings. The shrimp, which received animal food, grew faster. 20% of the females formed eggs. At the same time, their aggressiveness was high, which led to the loss due to injuries and cannibalism of 40% of the individuals. The shrimp, which received vegetable food, grew slower. Their final weight and size were significantly lower (P> 0.95) than those of shrimps of the first group with similar initial parameters. In the tank No. 1, a lateral flow of moderate force was created. Shrimps formed a sparse aggregation in the center of the tank avoiding the current. They did not take refuge, did not show aggression towards each other and did not protect their territory. In the tank No. 2, with similar conditions, there was no lateral flow. Shrimps were distributed evenly in the tank, took refuge and protected their territory, were aggressive towards other individuals, often entering into fights with them. With similar size and weight characteristics of shrimp in both cultivation variants (the difference is not significant P <0.95), no loss was observed in the first case, while it was 20% in the second case. Originality. For the first time, it was shown that the diet composition affects the growth, behavior and survival of M. nipponense shrimp. The use of vegetable feeds reduced aggressiveness and improved shrimp survival. Animal food increased the intensity of growth, ensured maturation of females, but increased the loss of shrimp due to cannibalism. Cultivation of shrimp in a tank with lateral flow of moderate force reduced traumatism and the loss of individuals due to aggressive behavior, with similar size and weight parameters. Practical value. Shrimp Macrobrachium nipponense is a promising object of aquaculture in the southern Ukraine. Increasing the yield of marketable production is an important aspect ensuring profitability of production. In this regard, the development of the methods, which allow reducing aggressiveness and increase the survival of shrimps in conditions of marketable cultivation is of great practical importance

Вплив абіотичних і біотичних чинників на ранній онтогенез кефалевих риб при штучному відтворенні

Температура і солоність середовища визначають ефективність запліднення, розвиток, зростання, виживання ембріонів і личинок. Межі температурного і сольового оптимуму змінюються в онтогенезі. Найбільш вимогливі до кисневого режиму лобань і сингіль, толерантні – піленгас і глоса. Вплив освітленості в ранньому онтогенезі кефалевих і камбалових риб видоспецифічний, а природний фотоперіод, обов'язкова умова нормального ембріогенезу. Максимальну швидкість росту мають піленгас і лобань, мінімальну, – глоса. Личинки глоси і лобаня, що перейшли на зовнішнє живлення можуть споживати кормові організми розміром 45-50, а сингіля, калкана і піленгаса – 60-70 мкм

Change of Spatial Distribution in the Ichiotocenosis of the Shabolat Estuary in the Process of Its Anthropogenic Transformation

Consequences of Shabolat estuary natural ecosystems transformation under the influence of anthropogenic factors are reflected in the composition of ichthyocenosis, changes in the basic population characteristics of the most mass species.The purpose of the work was to find out the spatial distribution of the Shabolat estuary most massive representatives of the ichthyocenosis in terms of its anthropogenic transformation.Material and methods. The material for the study was selected from industrial fishing gear in the spring, summer and autumn periods of 2009-2012. A complete biological analysis of fish (goby round, goby grass, flounder, flounder, mullet pilengas, etc.) was carried out according to the conventional method.Result. The regularities of formation of ichthyocenosis largest masses populations were studied depending on: water salinity, connection with adjacent water areas, fish acclimatization and introduction, anthropogenic loading and peculiarities of spatial distribution of ichthyocenosis largest masses populations in aquatics.The most important Shabolat estuary ichthyocomplex components include representatives of the Gobiidae family, the Platichthys luscus population and the mullet family representatives.Of particular interest to the members of the goby family are the mass species of gobies: the round goby Neogobius melanostomus and the grass goby Zosterisessor ophiocephalus, which are able to hibernate and reproduce in the estuary. This is an important link in the food chains of the reservoir. By entering into competition with other representatives of ichthyocenosis, they significantly affect the state of the forage base and production capacity of the estuary.Representatives of the mullet family and gloss flounder are distributed in the estuary deep water areas and in areas with maximum salinity.Conclusions. It has been established, that in the conditions of anthropogenic transformation of the estuary, in the last 35-40 years, the round goby and grass goby numbers and distribution range have decreased. In bulk, they have survived only in reservoir small, local areas, due to the deterioration of reproduction conditions and the degradation of the zoster and reddest associations. The main reasons for the decline in the size and distribution range of gobies in the Shabolatsky estuary was their mass death as a result of a large-scale environmental catastrophe and reproduction conditions deterioration. The reason for the significant decrease in the flounder and mullet number and distribution range was the mass death in 1992, as well as changes in the salinity of the Shabolat estuar

Characteristic of Feeding of Mullet Fishes in Shabolatsky Estuary

The worsening of the ecological situation in the last years resulted in the decrease of biodiversity and general fish productivity of the saltish-water Shabolatsky estuary, placed in Danube-Dniester interfluves. It doesn't allow to use it effectively for the traditional pasturable cultivation of mullet fish.The aim of the work was to study the features of feeding, food relations and growth of indigenous species of mullet (stripped mullet, leaping grey mullet, golden mullet) and soiuy mullet acclimater at the pasturable cultivation under conditions of Shabolatsky estuary. The collection of ichthyological material was realized in 2012-2014. At the study of mullet feeding were used standard methods that allowed to assess season changes of qualitative and quantitative parameters of feeding and food relations of mullet: stripped mullet - Mugil cephalus, golden mullet – Liza aurata, leaping grey mullet – Liza saliens, soiuy mullet – Liza haematocheilus.For the first time there was given the qualitative characteristics of feeding and food relations of different types of mullet in season and age aspects. It was demonstrated, that leaping grey mullet and golden mullet of all age groups in all seasons of a year prefer animal food; stripped mullet and soiuy mullet – detritus and vegetable food. The most similarity was inherent to the qualitative compositions of rations of yearlings of all mullet species in the spring period (feeding similarity index FSI – 63,0-76,5). In summer the food composition changed (decreased for animal plankton and increased for zoobenthos). The tension of food relations decreased (FSI – 49,8-75,0). In autumn the most similarity of the food character was typical for second-year golden mullet and leaping grey mullet on the one side and second-year and third-year stripped mullet and soiuy mullet (up to 75-89% of detritus and vegetable food) on the other one. At the same time golden mullet and leaping grey mullet essentially differed from stripped mullet and soiuy mullet by the food character. The decrease of zooplankton and zoobenthos production, noticed in Shabolatsky estuary in last years resulted in the decrease of the growth speed of leaping grey mullet and golden mullet. At the same time essential reserves of detritus of vegetable food provide the intensive growth of striped mullet and soiuy mullet.In the existent situation it is expedient to use striped mullet and soiuy mullet detritophages as main objects of the pasturable mullet cultivation to provide the maximal fish productivity of the water body