The article is devoted to the actual problem of soils with excessive moisture accounting based on the analysis of cartographic materials and satellite images with subsequent data processing. In the humid climate of the Kaliningrad region (South-Western Baltic States), about 80% of the soils are drained, so the study is aimed at assessing their hydrological state in agricultural landscapes. Potential areas of land subject to waterlogging are proposed to be allocated on the basis of a diagnostic soil indicator – the degree of gley. In conditions of drainage, gley soils (Gleic Albeluvusols, Umbric Gleysols, Eutric Histosols) are at the greatest risk of developing an unfavorable ecological and hydrological situation. In total, they make up 21.9% of the total area of agricultural land in the Kaliningrad Region (excluding alluvial soils) and 26.2% in the Zelenograd Municipal District. The study of the soil cover of the territory of 15 agricultural enterprises that existed in the 70s – 80s of the twentieth century revealed a strong spatial heterogeneity in the distribution of areas of gley soils with high coefficients of variation. A similar situation persists on modern arable land. The actual areas of soils subject to waterlogging were taken into account based on the analysis of satellite images taken in November – December and February – April 2016–2022 during the most typical periods of the development of an unfavorable hydrological situation. For four arable plots, it is shown that the proportion of waterlogged soils averages from 17.5 to 38.7% of the total field area. Variation of soil areas with unsatisfactory hydrological condition may be associated with the precipitation of large amounts of precipitation and their accumulation in closed depressions. Various violations of the drainage network leads to poor quality of its work to remove excess moisture from the fields. The results of ecological and hydrological monitoring soils with excessive moisture in the agrolandscapes are the basis for making decisions to optimize the reclamation state.

The article deals with issues related to the problems of eroded soils and the subsequent processes of development of serial communities on the way to the formation of a stable climax phytocenosis. A series is considered as a set of species that briefly exist in a given territory and replace each other. The development of soil erosion is due to anthropogenic and natural factors, so the process is of a mixed type - naturalanthropogenic. Soil erosion on slopes of any exposure of elementary landscapes affects the ecological conditions for the formation of phytocenotypes and the species composition of plant communities due to secondary successions. Plant communities of herbaceous phytocenoses of eroded soils are characterized by both sequential and sudden changes in species composition with the appearance of species adapted to a decrease in soil fertility. To pass through the stages of secondary successions, there is a sufficient supply of seeds that contribute to their distribution, germination and rooting, first as single individuals, then forming agglomerations, populations that, in the end, fit into the structure of the plant community, ensuring its spatial and temporal uniformity, observing the rules of sequential filling of the medium. The direction, speed and number of succession changes depend on the intensity of the development of erosion processes. Highly eroded soils create a significant increase in the heterogeneity of the soil environment - these are optimal conditions for the introduction of species that are not always typical for the considered phytocenoses, therefore the number of assectators increases on soils of this type. Taking weakly eroded soils as control, the number of assectators on highly eroded soils increases two to three times, while the situation is considered with possible fluctuation changes aimed at reducing assectators, which is associated with ecotopic and phytocenobiotic selections.

Many open-pit mining pits have been excavated within recent decades, therefore research on artificial reclamation and natural renaturalization of quarries is increasingly relevant. Despite the fact that many works are devoted to the study of the restoration of ecosystems of technogenically disturbed territories, there are aspects that require more detailed study. These include: identification of features of vegetation, due to zonal-climatic and technogenic-landscape features of specific areas.

This article presents the results of studying the floristic composition on the coast of the watered Yantarny quarry, where stable plant communities have formed over the past 50 years since amber mining was stopped. The features of the steep and gentle slopes of the flooded quarry are considered in terms of the peculiarities of species diversity of vegetation on such slopes; based on it the features characteristic of the flooded Yantarny quarry are identified. Differences were also found in the overgrowth of the coast, depending on the recreational load upon individual parts of the reservoir coastline. The projective vegetation cover of the coast is about 80%. It has been established that 47 species of vascular plants of four life forms belonging to 44 genera and 24 families grow on the coast of the watered Yantarny quarry. 20% of the total number of species are violenta-plants. Herbaceous and shrub vegetation predominates. Two species of invasive plants have been found. There is a transition to a climax community with woody vegetation. The greatest variety of vegetation species grows in the transition zone from the foot to the side slope of the quarry.

The Matrosovka River is the left arm of the Neman River, flows through the territory of the Kaliningrad region. It plays a significant role in the fisheries of the region, is a water receiver of numerous reclamation drainage systems. These problems are closely related to the water content of the river. Therefore, the analysis of the series of average annual water flow rate Q in the Matrosovka River is a very urgent task. The Mostovoye hydrological post, where water flow measurements are carried out, has been in operation since 1968. Moreover, there are no results for some years. The use of the Varta River (the right tributary of the Oder) in previously published works to restore the Q series of the Matrosovka River led to serious errors due to violations of the conditions of hydrological similarity. It is shown that the Neman River satisfies all the requirements for an analog river. A number of observations of Q in the alignment of the city of Smalininkai dates back more than 200 years. To restore the Q series of the Matrosovka River, the well-known method of E.G. Ivanov was used. Analysis of the parabolic trend and the integral-difference flow curve showed that the restored series can be divided into three periods by water content. The first was from 1812 to the mid – 70s of the 19th century with an average flow rate of Qs1 = 135.6 cubic meters/s. The second – until the end of the 50s of the 20th century, Qs2 = 142.8 cubic meters/s; the third – by 2020, Qs3 = 125 cubic meters/s. The hypothesis of uniformity of the series was rejected (according to the Student's criterion) due to the large difference between Qs2 and Qs3. The three-parameter gamma distribution Q was accepted as theoretical. The distribution parameters were found in three ways: 1) over the entire series, as homogeneous, 2) by a composite formula for three periods, 3) by a composite formula for the last two periods. The difference between the estimated costs Q of a given probability of excess found by these methods turned out to be less than 3%. Therefore, to determine them, it is possible to use a theoretical distribution calculated over the entire series as a single one.

For the first time, studies of amateur smelt fishing within the city of Kaliningrad during the spawning run of the smelt family (Osmeridae) were carried out. Thanks to the monitoring of recreational fishing in the spring season on the river. Preholiday, where smelt (Osmerus eperlanus eperlanus morpha spirinchus) and European smelt (Osmerus eperlanus eperlanus) come to spawn from the Vistula Lagoon, the localization of amateur fishermen, attendance of fishing grounds was determined, the analysis of catches, species composition, size structure of the target type and intensity of fishing. The calculation of catches for effort made it possible to establish the dependence of the mass character of fishing on the size of the catches, and the second on the values of water temperature. The value of catches per effort varied significantly from single specimens to an average kilogram of fish per hour of fishing. With the warming of the water, the catches reached their maximum values, which is caused by an increase in the efficiency of catching smelt these days. It has been determined that recreational fishermen are a good indicator of the spawning run, since some fishermen conduct “control catches” in advance to determine the presence of the target species in their catches, then proceed directly to the catch. Thanks to the calculated indicators, the final stage of the spawning run of the smelt family in the river was established. Pregolya. The final stage of the study was the calculation of the daily catch and the total catch of smelt by recreational fishing for the period of spawning migration, depending on the intensity of the spawning run and the mass character of recreational fishermen. According to the results of calculations for the entire observation period in 2023, the catch of smelt in the river. Pregolya amounted to 0.515 tons.

Authors developed a method for processing fish skin, which makes it possible to obtain a food hydrate. Method consists of skin preliminary cleaning from cuts in muscle tissue and the subsequent separation of fish scales. The resulting pikeperch skin was mixed in a container with water, food salt NaCl and soda NaHCO₃ taken respectively in a mass ratio of 100:400:5:1, kept for 40 minutes and washed with water. The cleaned skin was mixed with apple juice in a mass ratio of 1:10 and kept at 4 deg C for 6 days. During exposure (144 hours) in the juice, the weight of the skin increased by 4.47 times compared to its initial weight, while there was a decrease in the acidity of the juice from pH 3.54 to 3.70. Swollen after 48 hours of aging in juice, the skin was easily torn (without effort) and rubbed with fingers. To characterize the original skin and juice, as well as samples obtained during their joint exposure and taken every 24 hours during the entire process (6 days), the FT-IR spectroscopy method was used, which showed the presence of functional groups of collagens (amide A, B, I, II and III) in prototypes. The difference in wavenumbers between amides I and II in skin samples kept in juice was less than 100 cm^-1, which indicates the preservation of the triple helical structure of collagen. The resulting hydrate from fish skin (with the preservation of the native structure of collagen) can be recommended as an independent product, or as an additive in food products.

The paper presents survey data on the preferences of respondents in the diet. Studies have been conducted to improve the technology of bakery products: salted wheat straws and rye-wheat loaves (edges) and by enriching them with fish protein and protein-mineral additives. In the first case, the problem is solved by introducing fermented minced cod into the dough, obtained by holding the crushed muscle tissue of the fish in water at the specified parameters: the duration of fermentolysis (20 min) and the water temperature (20 ± 2°C). The baked finished product consists of round-shaped sticks, slightly curved, easily broken, from light yellow to light brown, well baked and without signs of non-kneading, with a pleasant salty taste and smell, with an unexpressed aroma of fish. According to the results of physico-chemical studies, the protein content increased by 66%, mineral substances – by 11%. In another case, a proteinmineral composition obtained by holding a crushed cod carcass in whey at technological parameters: hydrolysis time of 268 minutes and temperature of 28 °C. The finished product was presented in the form of loaves (edges) made by baking the finished dough with the introduction of a protein-mineral composition and malt extract into the recipe. The rectangular loaves had a pleasant, sweet aroma and malt taste and had a uniform dark brown color with a well-loosened, uniform structure. The introduction of malt extract into the formulation also enriches the product with fiber and protein substances and improves the organoleptic characteristics of the finished product.

Increased volumes of waste from fish cutting containing rapidly perishable fats are currently a problem in many fish processing industries. This raw material is traditionally used for the manufacture of feed fishmeal and industrial fat. However, smoked fish waste is not processed due to the content of smoke components that are toxic to animals. The fatty fraction of fish waste contains valuable fatty acids, including polyunsaturated PUFAs and omega-3 acids, which are necessary for the normalization of many body functions. In the work, the biopotential of fat from smoked fish waste from sprat production was studied, the thermal process of its extraction was optimized, the quality and safety of sprat fat were assessed, and rational directions for use were substantiated. The chemical composition of hot-smoked sprat heads and the fatty acid composition of the extracted fat were studied. Experiments were carried out to optimize the thermal extraction of fat from fish waste using mathematical planning of experiments. Coded and natural mathematical models have been obtained that relate the quantitative yield of fat and its safety indicators with the temperature and duration of thermal exposure. Sprat waste fat in the experiment in terms of hydrolytic and oxidative spoilage (acid and peroxide numbers) did not always meet the requirements of the standard for edible fish oil. The content of polycyclic aromatic hydrocarbons (benz(a)pyrene; benzo(b)fluoranthene; benzo(a)anthracene; chrysene) with carcinogenic properties in sprat fat was studied. The results indicate the criticality of its use for food purposes in the form of raw fat. Microbial biotechnology and its use as a carbon source for the synthesis of unicellular proteins and biodegradable plastics is seen as a rational area for the application of fat from smoked fish waste with a high content of hazardous substances.

The article presents the results of studying the process of plum fermentation, which belongs to the regional stone fruit raw material. A microbiological analysis of fresh plums was carried out to establish the quantitative and qualitative composition of the initial microflora, which plays a major role in the fermentation process. It has been established that the main composition of the microflora of fresh plums is coccal and rod-shaped bacteria of lactic acid fermentation. The technology of fermentation of plums, carried out by spontaneous fermentation without the addition of brine from the previous fermentation and without the introduction of starter cultures of microorganisms, is described. The results of various plum fermentation methods (in the presence of oxygen and without it) are shown. It was revealed that an oxygen-free environment promotes the reproduction of anaerobic lactic acid bacteria, lactobacilli convert sugar into lactic acid, the pH of the finished product decreases to 3.18, a low pH value contributes to obtaining a safe product with a long shelf life. At the same time, the lacto-fermented plum acquires new organoleptic properties – a brighter color, an individual and unique taste, sourness and a new depth appear, the texture changes. Showing quantitative and qualitative changes in the microflora during fermentation (7 marmots) in various ways. The microbiological safety of the studied samples of lacto-fermented plum was confirmed. They differed in storage stability and microbiological stability in relation to sanitary indicative bacteria of the intestinal group and spoilage microbes. On the basis of lacto-fermented plums, the following products were obtained: pulp, juice, powder (powder) from the peel of the fruit. Their total bacterial contamination and composition of microflora were studied. The ways of practical application of the developed products are indicated and shown: as an appetizer, garnish for meat, poultry and fish, salad dressing, sauce for seafood, ingredients for dessert.

The article presents theoretical and experimental studies to justify the possibility of controlling supply of liquefied natural gas (LNG) to the engine cylinder. At present, most gas engines have operating cycle with constant volume combustion (N. Otto cycle). This is due to difficulty of supplying natural gas in top dead center region. N. Otto cycle significantly loses in efficiency to combined cycle with combustion at constant volume and constant pressure (G. Trinkler cycle). The experiment was carried out on marine diesel engine “NVD-24” stand on a mixture of diesel fuel and petroleum gas in various proportions, at idle and with partial engine load. It has been established that liquefied petroleum gas under pressure is mixed with diesel fuel in any proportions, while mixture remains a homogeneous liquid, without visible precipitation and stratifycation. Calculations of theoretical cycles have been performed, showing the advantages of the injection of a combustible mixture at the top dead center, in comparison with preliminary carburetion. During the experiment, it was found that an engine with a spool injection pump and a spring nozzle, can operate stably using a liquid mixture as a fuel without adding additives. An increase in the effective efficiency of the engine with an increase in the concentration of LNG in the supplied fuel mixture has been established. In this case, fuel mixture pressure must be greater than critical pressure of the gas mixture. Formulas for calculating advance angle of fuel supply to the top dead center and angle of delivery behind the top dead center are obtained. The performed calculations in relation to “NVD-24” engine show that Common Rail fuel supply system with a piezoceramic injector can ensure the operation of the engine in a combined cycle. This organization of workflow makes it easy to upgrade both new engines and those in operation. In this case, fuel supply can be performed on all engines, regardless of presence of gas turbine pressurization.

Fishing in the coastal marine zone in the Russian Federation is currently carried out by small fishing vessels of domestic and foreign construction. The vast majority of vessels have exhausted their resources and require replacement, while foreign-built vessels show more efficient operation compared to domestic counterparts. Measures to modernize Soviet and Russian vessels do not give the desired effect. Information on modern foreign fishing vessels is classified or very limited. Because of this, the designers are faced with the task of modernizing existing vessel designs and / or creating a design for a new competitive fishing vessel for efficient operation. An analysis of modern foreign vessels information shows that all small fishing vessels basically have two types of hull – "Icelandic" and "Norwegian", characterized by an increased completeness of contours. Studies of modern small fishing vessels with a large hull density, by testing physical models in the towing tank, made it possible to determine the main elements of vessels that significantly affect seaworthiness. This paper describes a series of tests of physical models of ships in the towing tank. Based on the results of these tests, the main elements of small fishing vessels with a large hull density, which largely affect certain seaworthiness, were identified. Based on the results obtained, recommendations were formed and presented for use in the modernization of projects of small fishing vessels and / or the creation of new vessel designs.