Rybohospodars'ka nauka Ukrayiny (Fisheries Science of Ukraine)

17-25

Authors: Е. Arystarkhova

Purpose. An increase in the informativeness and shortening of the timing required for biotesting of water from surface water sources in the city of Zhytomyr with the use of Danio rerio Hamilton-Buchanan instead of the traditional test object Poecilia reticulata Peters and observation of their ethology using the «time sampling» method. Methods. Water samples were collected from reservoirs of the Teteriv river in April 2016. They were used placed in aquaria (10 dm3), where control and experimental groups were formed according to the following scheme: control group – samples with settled (24 hours) tap water; experimental group D-1 - water samples from the Denishivsky reservoir; experimental group D-2 – from water intake Vidsichne. Test specimens were females of P. reticulata and D. rerio, in which the parameters of typical and non-typical motor activity and feeding behavior were determined. Fish were exposed to water for 12 hours. Water toxicity indexes were determined for both experimental and control groups. Findings. The studies showed the possibility of using the "time sampling" method for rapid assessment of the water toxicity of surface water sources of Zhytomyr with the use of P. reticulata and D. rerio, which consists in the instantaneous fixation of the number of individuals preferring different behavior acts. D. rerio were more susceptible to the combined action of pollutants in experimental waters than the traditional test object guppies regarding the test reactions of increasing the vector movement and reducing the activity of consumed feed (in 12 hours after the start of biotesting on average by 8,43% in the group D1 and by 11,71% in the group D2). The calculation of toxicity indexes based on the above-mentioned ethological acts, which exceeded 50%, detected an average level of pollution of the experimental water. Originality. For the first time, the rapid assessment of the water toxicity of surface water sources in the city Zhytomyr was carried out by observing the motor activity and feeding behavior of D. rerio. Practical value. The results of the research are used for the rapid assessment of the toxicity of water of surface water sources in the city Zhytomyr.

37-49

Authors: К. Heina

Purpose. To provide the biological assessment of the silver Prussian carp (Carassius auratus gibelio (Bloch, 1782)) commercial stock of the Dnieper-Bug estuary in the conditions of the transformed Dnieper river flow. Methodology. During the analysis of the biological state of the Prussian carp commercial stock, the main attention was given to the dynamics of age and sexual structure, length-weight growth rate, absolute fecundity and condition factor. The basic data were collected during the work of control-observation stations of the Institute of Fisheries in the Dnieper-Bug estuary during the current century. The collection and processing of ichthyological materials were performed in accordance with the generally accepted methodologies. Findings. The analysis showed that during the current century, the age structure of the Prussian carp of the Dnieper-Bug estuary was the most labile among other commercial cyprinids. It was found that as a result of an increase in the right wing of the age series, there was a gradual increase of the mean weighted age of its commercial stock. At the beginning of studies (2001-2002), the core of the stock was formed by age-3-6 fish (up ); however in subsequent years, a displacement of dominant groups toward the dominance of age-4-7 fish (more than 80% of the total stock) was observed. At the same time, the relative number of age-3 fish (recruits) was at a relatively high level – up to 10.6%. The linear growth varied more intensively until the age-5, but it reduced with ageing and did not show high variability. The body weight most variable was in age-4 fish (Cv=9.62%). The noted insignificant deviations in the body weight growth rate of the right wing of the age series was due to stable predominance of females in the stock structure, which were characterized by a variability of the mean weight as a result of different development of gonads. The dynamics of the age-related changes in the condition factor indicated on a gradual decline Fulton condition factor from 3.47±0.22 in age-3 fish to 3.12±0.06 in age-6 fish. The highest variability of these indexes was typical for age-5 fish (Cv=10.9%; lim=2.46-3.89), that was related to the linear-weight growth and fecundity. With an increase in the age, the variableness of condition factor reduced substantially. Originality. The paper contains modern and significantly updated data on main biological characteristics of the Prussian carp commercial stock in the transformed conditions of the Dnieper-Bug estuary. Practical value. The obtained results are a scientific background for rational fishery optimization of commercial pressure on the representatives of valuable fish fauna of the Dnieper-Bug estuary. In current conditions, the presented information is actual enough from the point of view of the maintenance and support the biodiversity of valuable commercial species in natural water bodies of Ukraine.

65-75

Authors: Р. Mendrishora, А. Mruk, G. Kurinenko

Purpose. To analyze the results of morphometric measurements and dates of aquaculture-biological characteristics of the young-of-the-year and age-1+ rainbow trout reared under industrial technology at instable conditions of the fish farm “Sloboda-Banyliv”. Methodology. The study has been performed at the industrial fish farm “Sloboda-Banyliv”, Chernivtsi region. The materials for the study were young-of-the-year and age-1+ rainbow trout obtained from the eggs of autumn-spawning form rainbow trout. The young-of-the-year were reared in a 216 m2 tank with stocking density of 255 ind./m2, age-1+ fish were reared in 108 m2 tank with a stocking density of 33 ind./m2 according to generally accepted methods in trout culture. Morphometric measurements of fish were performed according to I.F. Pravdin. Statistical processing of data was carried out in Microsoft Office Excel (2003). The analysis of values was done in the system of absolute values. The analyzed criteria of the measured parameters were their mean values and standard errors (M±m), deviation (σ), variability coefficient (Cv). Fish were fed with the artificial feed with high protein content manufactured by “Biomar” (Denmark). Findings. The studies on rainbow trout rearing under industrial conditions showed that fish body proportions did not change with age, however, the length of their fins decreased. The slenderness coefficient in age-1+ fish decreased insignificantly that is typical with increasing body depth. Despite instable rearing conditions, both young-of-the-year and age-1+ fish were characterized by moderate growth rate and high feed-conversion efficiency. Originality. For the first time, in conditions of Ukraine, a study on the formation of rainbow trout brood stocks in a fish farm with instable rearing conditions was performed with the use of the analysis of phenotypical and productive features. Practical value. The results of the performed work will provide an opportunity to form a rainbow trout brood stock based on characterized phenotypical and productive features that would have high productive and reproductive features in a fish farm with instable rearing conditions.

83-97

Authors: I. Kononenko, A. Pugovkin, R. Kononenko, V. Cherepnin, K. Buts’kyy, Ye. Kopeika

Purpose. To optimize the conditions of sterlet sperm cryopreservation for works on egg fertilization and for producing viable offspring in the conditions of sturgeon farms. To analyze the effect of sperm freezing in different forms on spermatozoa survival and egg fertilization. To compare the results of cryoprotective solutions with compositions on the results of their use of sterlet sperm fertilization and to analyze their effect on the quality of the produced offspring. Methodology. The task aimed at optimizing the conditions of sterlet sperm cryopreservation for egg fertilization in the conditions of fish farms were carried out according to generally accepted methods in cryobiology and recommendations of Ye.F. Kopeika. The works with the produced sterlet offspring were carried out according to conventional sturgeon culture methods. Findings. The studies showed that the optimization of the conditions of sterlet sperm cryopreservation allowed preserving the properties of thawed spermatozoa at the level of native sperm. It was found that the functions of the sperm cryopreserved in liquid nitrogen vapors in granules in solutions with methanol or dimethyl sulfoxide (DMSO) were better preserved in granules when using methanol. The functions of the sperm after its freezing in cryopreservation solutions №№ 5 and 6 were evaluated in the conditions of a fish farm. It was found that the fertilizing capacity of the cryopreserved sperm in the solution № 5 (85.6 %) (with lower osmolality) did not virtually differ from the control (87.6 %) when using 25-60 g of eggs. In the cryopreservation solution № 5, this value was 17.6 % lower. The weight and length gain after egg fertilization with the sperm cryopreserved in both solutions in 3-month fish was higher than in the control. Originality. Introduction of creatine and fructose into the cryopreservation solution allowed increasing its protective properties and preserving spermatozoa activity after thawing at the level of the native sperm. Sperm cryopreservation in granules allowed optimizing the conditions of low temperature freezing of this sturgeon species and producing high quality viable offspring. Practical value. The obtained results can be used by sturgeon culturists in the conditions of fish farms for works aimed at producing viable sterlet offspring both for commercial purposes and for restocking into natural water bodies as well as by cryobiologists for works with other fish species.