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.
Key words: National Nature Park “Tuzla lagoons”, fish fauna composition, distribution, fisheries exploitation.
Purpose. To investigate the potential of zooplankton productivity in aquatic ecosystems under experimental conditions of the microcosms with the use of the green fertilizer (vetch-oat grass) and Ekovital.
Methodology. The study was conducted under the conditions of model ecosystems (microcosms) installed in fish-breeding ponds. We used a complex of intensification measures (enhancement, inoculation of vetch-oat seed mixture (1:1) with Ekovital at quantities of 1.4; 2.9; 4.3 ml/kg (variants D1, D2, D3), followed by sowing the pond beds with the vetch-oat mixture (1:1), growing of vetch-oat grass for the green fertilizer). The seeds were sown at a ratio of 70 kg of grains for 1 ha of ponds area. The first control variant (K1) — without green fertilizer and without preparation. The second control version (K2) vetch-oat seeds were soaked in the corresponding quantity of water without preparation and after they were sown on the pond bed. The preparation Ekovital contains specific nitrogen-fixing nodule Rhizobium leguminosarum and phosphorus mobilizing Bacillus megaterium-6 bacteria. Hydrochemical, hydrobiological, fisheries, and statistical studies were conducted according to standard methods.
Findings. It was found that the application of Ekovital in a combination with enhancement activities gives an opportunity to obtain a green fertilizer of up to 1.03 ± 0.08 t/ha during 40 days for increasing pond ecosystem productivity.
The stimulation of zooplankton development gave an opportunity to obtain the maximum biomass of 9.85–31.78 g/m3 that was 4–16 times higher than in that in the control — 2.54–3.30 g/m3. The mean values of zooplankton biomass in the experiments were 4.30–9.17 g/m3, that was 3-9 times higher than those in the control — 1.06–1.40 g/m3. The experimental variants showed a tendency for increasing the share of cladoceran crustaceans.
The production of zooplankton organisms was increased to 1834.8 kg/ha — the level of the most productive breeding ponds of the forest-steppe zone of Ukraine.
The potential of natural fish productivity of an aquatic ecosystem based on zooplankton when applying the green fertilizer (vetch-oat grass) and Ekovital showed a 3–7 time increase compared to the control. The maximum potential natural fish productivity based on zooplankton was achieved at the level of 152.90 ± 85.25 kg/ha in the variant D2.
Originality. For the first time we presented the results of the studies of zooplankton community productivity in fish-breeding ponds with the use of the green fertilizer of vetch-oat grass and bacterial preparation Ekovital under the conditions of model ponds ecosystems (microcosms).
Practical value. The received results are the basis for further studies on the use of a method for increasing natural fish productivity in fish-breeding ponds with the use of a green fertilizer such as vetch-oat grass and Ekovital.
Key words: green manure, zooplankton, Ekovital, natural forage, fish-breeding ponds, natural fish productivity.
Purpose. The study was aimed at raising young-of-the-year European grayling and improving the industrial technology with the use of specialized artificial feeds.
Methodology. The work on raising young-of-the-year European grayling was carried out in 2014 at the fish hatchery “Lopushno”, Chernivtsi region, during five months (May – September). YOY were obtained from 22 age-3–4 brood fish, which were kept in ponds of the natural reserve “Synevir”. Culture-biological parameters of brood fish were determined based on Pravdin (1966) method for salmonids. To avoid traumatization of fish, they were kept in the anesthetic “Propiscin” before the collection of sexual products. The condition factor was determined by Fulton’s formula.
Findings. The mean weight of brood fish used for spawning was 110 g with the mean body length of 22 cm. Fulton’s condition factor of European grayling was: 1.1 in females and 1.0 in males. Feeding of larvae was as follows: starting feeds — live feeds (Cyclops, Moina), then the alternation of live feeds and a specialized starting feed for 30 days, and the artificial feed after. Raising European grayling from larvae to young-of-the-year was carried out in trays of different sizes from 0.5 m2 to 4.5 m2, water level in trays was increased according to fish growth from 20 cm to 42 cm. Water supply was 60 L/min, thus the rate of water exchange was from 0.5 to 1.7 times/hour that corresponded to technical norms for salmonids. Mean weight of the young-of-the-year on September 10 was 17.1 g, mean length was 11.8 cm.
Originality. Consists in the comprehensive assessment and development of an integral mechanism of scientific principles and methodical recommendations on artificial reproduction of European grayling.
Practical value. The results of the work will be used for the works on the reproduction of valuable fish species in aquaculture facilities of the Carpathian region.
Key words: European grayling, larvae, young-of-the-year, feeding, artificial reproduction.
Purpose. To investigate the specificity of the genetic structure, intra- and interpopulation genetic variability of the pedigree stocks of bighead carp in different fish farming zones using DNA markers (ISSR-PCR).
Methodology. To investigate the specificity of the genetic structure we used a PCR (ISSR-PCR) method with appropriately selected primers.
Findings. As a result of the study of the pedigree stocks of bighead carp, we carried out an analysis of the genetic structure by using three microsatellite DNA loci (CTC)6C, (GAG)6C, (AGC)6G. The investigated populations accumulated a reserve of the genotypic variability in different parts of microsatellite loci. The identified specific properties among the investigated bighead carp populations can characterize the heterozygosity degree of the stocks reared in these fish farms. The variations in the detected amplicons are sufficient for separating the individuals of breeding stocks, or, if the work is carried out with a group of brood fish, to select parent pairs for increasing the genetic diversity.
The described variability of the genetic structure by specific gene sites and distribution of markers in fish stocks indicate on significant level of genetic variability that is a basis for determining the level of their adaptability in the process of artificial selection in fish farms of different forms of ownership.
Originality. We detected the peculiarities of the genetic structure, the level of genetic variation of the pedigree stocks of bighead carp in different fish farming zones with the use of DNA.
For the first time we obtained new data on the specificity of the genetic structure based on PCR, which contribute to the detection of the specific mechanisms of maintaining the relative stability of bighead carp genetic pool and allow controlling the specificity of their genetic structure.
Practical value. The practical value of the study is to propose a method of the genetic control of bighead carp populations by applying a PCR that allows performing an analysis of the genetic structure of the stocks and realizing the genetic information on early stages of the breeding process.
Key words: molecular genetic methods, DNA markers, bighead carp, genetic structure, PCR.
Purpose. Studying the peculiarities of the genetic structure of different age groups of silver and bighead carps from fish farm Limanske with the use of genetic-biochemical markers.
Methodology. The methods of vertical polyacrylamide and horizontal starch electrophoresis with our own modifications have been used for the study. Sampling of the biological material and histochemical staining of gel plates were carried out using the generally accepted methods. Statistical analysis of the obtained data were performed in "Biosys-I".
Findings. We analyzed the genetic structure of age-1, age-1+ and age-2 of silver and bighead carps with the use of genetic-biochemical markers - Рralb, EST, MDH, МЕ, СА. We demonstrated the peculiarities of allele frequencies and genotypic composition of protein system loci. A high level of heterozygosity in the examined was detected loci for age-1 silver carp – 66.7-88.9% and age-1 bighead carp – 65.4-77.8%. A significantly higher level of the observed average heterozygosity compared to the expected heterozygosity of age-1 as silver carp (Ho = 75.9%, He = 49,6%), and bighead carp (Ho = 73,6%, He = 47,9%) was observed. This fact indicated on the necessity for performing a stabilization of their genetic structure. The calculated Wright's F index in different age groups showed a predominance of the observed level of the average heterozygosity over the expected one for 22.7–53% in silver carp and 24.5-53.7% in bighead carp. A stabilization of the genetic structure in age-2 silver carp (Ho = 57.8%; He = 47.1%) by the heterogeneity level was observed.
Originality. For the first time we analyzed the genetic structure and the level of heterogeneity of the breeding groups of age-1, age-1+, age-2 silver and bighead carps from fish farm Limanske with the use of genetic-biochemical markers.
Practical value. The results of the study can be used in selection and breeding works aimed at creating the breeding stocks of silver and bighead carps to control the level of interspecies genetic variability. The obtained experimental data of the genetic structure analysis of silver and bighead carps of different age groups will be used for the monitoring of the genetic structure changes during their adaptation to new environmental conditions.
Key words: silver carp, bighead carp, age-1, age-1+, age-2, genetic-biochemical markers, genetic structure, alleles, genotype, heterozygosity.
Purpose. To determine the effect of skin secretions in Percidae family of fish (Sander lucioperca, Perca fluviatilis) on the cultures of pathogenic E. rhusiopathiae bacteria.
Methodology. Filter paper was placed on the skin of live fish; after 1 minute it was removed, and the extraction of water-soluble components in the rate of 0.1 cm3 of water per 1 cm2 area of the paper was carried out. The resulting solutions of the secretions of fish skin glands were sterilized by vacuum filtration through the filters with a pore diameter <0.2 micrometers. The cultures of E. rhusiopathiae bacteria, which were used for testing, were grown in brain-heart broth for 48 hours at a temperature of +36.7 ± 0.3 °C.
The test samples contained E. rhusiopathiae cultures and fish skin secretions in 1:10, 1:100, 1:1000 and 1:10000 dilutions. The control samples contained a similar ratio of sterile water and cultures of the experimental bacteria type. The content of E. rhusiopathiae cells in the experimental and control samples was determined after 48 hours, the samples were stored at a temperature of +18... +20 °C.
Findings. The presence of water-soluble extracts of skin secretions obtained from Percidae family of freshwater fish in the environment causes an increase in the density of E. rhusiopathiae bacteria cultures. The degree of the detected stimulating effect of E. rhusiopathiae directly depend on the concentration of the secretions of fish skin glands in the experimental samples.
Under the conditions of freshwater ecosystems, such fish as S. lucioperca and P. fluviatilis and E. rhusiopathiae bacteria may form biocenotical relations of the trophic, topical and phoric types.
Originality. The quantitative data proving the biological activity of skin secretions in Percidae family of fish with regard to E. rhusiopathiae pathogenic bacteria have been obtained for the first time.
Practical Value. One of the factors contributing to E. rhusiopathiae bacteria staying in freshwater conditions for a long time can be their biocenotical relations with the components of freshwater biocenoses, including such fish as S. lucioperca and P. fluviatilis.
When carrying out measures aimed at preventing and eliminating the outbreaks of infections caused by E. rhusiopathiae, it is necessary to consider the possibility of the persistence of these pathogenic bacteria on the skin of freshwater fish.
Key words: Sander lucioperca, Perca fluviatilis, skin secretions, biological activity, Erysipelothrix rhusiopathiae, stimulating effect.
Purpose. Identification and analysis of age and seasonal dynamics of the symbiocenoses of grass carp and silver carp in fish ponds.
Methodology. The work was performed at Belotserkovskoy hydrobiological station, located on the river Ros within Belaja Cerkov. The objects of the study were symbiotic communities of grass carp and silver carp of different age groups (from yearlings to age-5 fish). Fish underwent partial parasitological dissection using generally accepted methods.
Findings. The age and seasonal dynamics of the symbiotic communitues of grass carp and silver carp were investigated during different seasons of one year. The effect of different factors on the formation of symbiotic communities have been analyzed. Different species of symbiotic organisms were characterized by different temperature preferences (Peritrcha have the highest rates of invasion in the summer). The distribution of symbionts depend on the way of their transmission. Some species of protista, monogenea and parasitic crustaceans infect the host during their high density (wintering or spawning). Other species of symbiotic organisms infect the host by nutritional way, therefore the invasion rates increase with the intensity of feeding. The differences in symbiotic community structure of fish of different age group are related to the differences in species biology. The composition of symbiotic communities of fish of different age groups contain symbiotic organisms that do not depend on the host age (metacercaria of Diplostomum, some Protista); species that more rapidly infect fish juveniles (some species of ciliates, cestoda – B. acheilognathi) and species that predominantly infect older age group (monogenea, parasitic crustaceans).
Originality. For the first time, we performed complex investigations of symbiotic communities of grass carp and silver carp in view of the specificity of their biology and during different seasons.
Practical value. The results of the work can be used for the development of optimum periods for pest control and prevention of epizooties as well as for controlling some species of parasites.
Key words: symbiotic community, seasonal dynamics of symbionts, age dynamics of parasites.
Purpose. To substantiate theoretically the optimum safety factors of fishing materials used for the construction of fishing gears that allow reducing the material consumption of these gears and keep them for a long time operation. To select the optimum color of polyamide materials with the lowest loss of strength.
Methods. The choice of the materials for the tests was based on the selection of the materials, which are most often used for active and passive fishing gears. Acid dyes were used to dye the materials. Dying was carried out in accordance with the technological instructions. The experiments were conducted at the Department of "Industrial Fishery" of the Kerch Sea Institute. The obtained results of all tests were processed using statistical method of random variables according to Sturges method.
Findings. The dying reduces the initial strength of the material by 10% and increases its service life. A relationship was established between the loss of nylon material strength and color as well as insolation time. The lowest loss of strength was observed in materials dyed in brown color. We developed the equations of relationships allowing adjusting the norms of the rate of the wearing of fishing gears. The safety factor of 4.62 was obtained experimentally and this value ensures the uninterrupted usability of a fishing gear during the exploitation period.
Originality. Based on the system integrated experimental and theoretical studies of the loss of strength of thread and netting materials, for the first time we developed the mathematical relationship for the loss of strength of kapron fishing materials depending on the time of insolation that allows predicting the degree of their wearing during the exploitation of various types of fishing gears.
Practical value. The obtained equations of the relationship between the loss of strength of fish netting materials and the time of exposure to sunlight are used in the calculation of wearing rates for beach seines, hoop nets, and fish net cages. The use of the recommended materials with the estimated safety factor will allow increasing the service life of fishing gears.
Key words: Netting, fishing threads, acid dyes, standards of wear, coefficient of durability, fishing gears.
Purpose. Creating of the thematic bibliographic list of publications dedicated to ecological and zoogeographical, morphological and biological, physiological, biochemical and genetic characteristics of the Danube salmon, as well as to its cultivation in Ukraine and abroad.
Methodology. In the process of systematic search complete and selective methods were applied. The bibliographic core have been formed by the literature from the fund of scientific library of the Institute of Fisheries NAAS.
Findings. There was composed the thematic list of publications in a quantity of 100 sources, containing characteristics of Danube salmon as representative of salmonids. Literary sources was arranged in alphabetical order by author or title, and described according to DSTU 7.1:2006 «System of standards on information, librarianship and publishing. Bibliographic entry. Bibliographic description. General requirements and rules», as well as in accordance with the requirements of APA style – international standard of references.
Practical value. The list may be useful for scientists, practitioners, students, whose area of interests covers the questions of breeding, and researching of the salmon biological features.
Key words: Danube salmon, distribution, reproduction, endangered species of fish, genetic features.