The study is devoted to the use of an integrated approach to the research of fish spawning migration into the river basins of the Vistula Lagoon. The fish spawning migration into the Prokhladnaya River in 2019–2020 has been studied. The number of spawning migrating fish in lower river was estimated by echo-sounder and species and size structures of fishes was carried out based on catch data from gill nets with a mesh 14–60 mm in the lower part of the river. The most numerous species of the catches are roach, bream, and bleak, accounting for 77% of the total biomass. The small-sized fishes in the catches are roach, bleak and ruffe. The fish examples with a body length of 14–24 cm are silver bream, roach and perch. Large-sized individuals are represented by bream, less often pikeperch. Fishes over 47 cm in length are represented in the catches only by pike. The spawning migration begins in the first decade of April when the water temperature reaches 7–8 deg. C, and the mass migration begins at a water temperature of 11–12 deg. C. The daily dynamics of the spawning migration in these years does not undergo significant changes. There was a more than two-fold decrease in the total number of migrating fish in 2020 compared to 2019. A similar size-species structure of the ichthyocenosis of the Prokhladnaya River in 2019–2020 has been established. The differences in the intensity of the spawning migration in these years are probably due to the low water level in 2020 and presence of a barrier in the form of a silted river mouth, preventing the free entry of fish to their spawning grounds.

The scientific article examines the problems of a stable equilibrium state of natural systems on the territory of a specially protected area – the Curonian Spit National Park. The predominant type of anthropogenic influence on changes in natural complexes is tourism and recreational activity. In this regard, emphasis has been placed on studying the species composition of plants in the recreational zone along the boundaries of the specially protected territory, since this territory is one of the most vulnerable and unstable. To assess the degree of conservation of the natural environment in the selected key areas, plant communities have been determined; the type of forest in the vicinity of the village Lesnoye has been identified. Based on the monitoring data, a comparative analysis of Jaccard groupings has been carried out, where the percentage of participation has been identified. All studies to assess vitality, abundance, and plant cover have been carried out at the stage of generative maturity of plants – g2. The dominant tree species are Pinus sylvestris L., Pinus mugo Turra, which are introduced species. Taking into account the changing dynamics of the total share of recreational space in the national park in relation to the protected zone, the data obtained indicate a careful expansion of natural boundaries at the boundary of recreation and the ecological features of protected natural complexes. The load of the recreational zone meets the requirements for such areas. Carrying out regular geoecological studies allows us to scientifically state current information on the state of the tree, shrub and herbaceous layers. This approach is aimed at preserving the historical, cultural, natural complex formed as a result of long-term transformation along the entire length of the Curonian Spit.

In the food industry, lobe pumps are used to pump working media, which are among the most difficult to manufacture. At the same time, pumps of this type have a number of advantages: low operating costs, long service life and careful movement of food masses without damaging their structure. This paper examines the performance characteristics of Russian-made lobe pumps with the aim of developing a method for assessing performance characteristics based on the parameters of the technical passport. It has been established that with an increase in the dimensionless coefficient of dynamic viscosity, both the flow and the expended power of the lobe pumps of the KNP series of Russian production increase, but with an increase in viscosity its effect on the flow decreases, and on the expended power it increases. At the same time, the calculation results show that with an increase in the viscosity of the pumped liquid, the energy efficiency indicators first improve and then begin to deteriorate. This is due to the fact that pumping more viscous food masses requires large energy costs. A hydraulic calculation of the process pipeline when pumping food mass (processed cheese) has been carried out, which showed that when transporting highly viscous products, a decrease in the diameter of the pipeline has little effect on the flow, but leads to a noticeable increase in hydraulic losses, consumed power and a deterioration in the energy efficiency of the installation. A method has been proposed that will allow one to obtain approximate performance characteristics of Russian-made lobe pumps based on an analogue pump. The characteristics of the lobe pumps obtained in this work make it possible to calculate the flow rate, pressure drop and consumed power at the operating point for a given process pipeline.

The goal of the work was to obtain the parameters of a numerical mathematical model of the MAG-3/1100 autoclave, widely used by enterprises in the Kaliningrad region for the sterilization of canned meat and fish. At the stage of analyzing the autoclave as an automation object, control points for the main technological parameters of the sterilization process have been established, taking into account the design features of the horizontal autoclave. A functional diagram of the process of sterilization of canned meat using a horizontal autoclave MAG-3/1100 has been developed and a description of its operation has been given. The programmable logic controller OWEN PLC210-04 has been selected as the autoclave control device in the automatic sterilization temperature control system. An algorithm for implementing the identification of parameters of a mathematical model of an autoclave using experimental data of the sterilization process obtained at the ARGO meat-packing plant in Kaliningrad has been considered. Identification of the mathematical model of the autoclave is represented by the transfer functions of the first order aperiodic link with delay. By modeling the dynamics of temperature changes using the Solid Thinking Embed package, the parameters of the numerical model have been determined. Using the obtained values of the autoclave model parameters, the optimal parameters of the PID controller in the automatic sterilization temperature control system have been determined using the engineering method. In the mathematical model, the maximum deviation of the temperature value from its actual value in the autoclave was no more than 2 °C. Using numerical identification parameters, a control program for the horizontal autoclave MAG-3/1100 has been developed in the application development environment CODESYS V3.5, and the organization of an automated workstation for the operator of the control of the horizontal autoclave has been proposed for operational monitoring of current temperature and pressure values in order to make management decisions in the sterilization process control system.

The research is aimed at developing an economically acceptable way to involve a practically unused by-product of the processing of spawning Baltic herring, scales with its caviar firmly attached to it, into the industrial production of food additives. The general chemical composition of dried herring spawning scales has been determined (protein – 67.89%, ash – 19.08%, fat – 0.14%, moisture – 12.10%), as well as its scales cleaned from caviar (protein – 38 .01%, ash – 48.27%, fat – 0.20%, moisture – 12.90%). It has been revealed that the process of drying (hot air) of herring spawning scales is accompanied by the formation of lumps, which must be constantly crushed. Subsequent grinding (knife mill) of the resulting dried product leads to the rapid formation of a monolithic plastic mass and stopping the equipment. In order to optimize the drying process and subsequent grinding, it has been proposed to mix the spawning scales of herring with plant raw materials (crushed wheat) in a mass ratio of 30:70 before processing, which helps prevent the formation of lumps and reduces the duration of the dehydration process, and also allows Grind the dried mixture to a slightly coarse flour. The resulting product, in the form of flour, has been used as a breading mixture for semi-finished culinary products (chilled perch and cod fillets, carrot and meat cutlets, cottage cheese) before their heat treatment. The paper presents changes in mass of experimental and control (breaded with wheat flour) samples of culinary products before and after frying in oil. It has been shown that a breading mixture consisting of spawning scales of herring and wheat improves organoleptic quality indicators and reduces weight loss of culinary semi-finished products during frying compared to the control.

Currently, there are more than 50 large and small enterprises in the fish processing industry operating in the Kaliningrad region. Secondary raw materials, which inevitably arise during the technological process, are in most cases disposed of in landfills or supplied to livestock feed in an unprocessed form. The resulting waste (bones, fins, heads, skin and scales) contains a large number of substances important for the human body, such as amino acids, biopolymers, macro- and microelements. The availability of accessible technologies for deep processing of such raw materials is an important factor not only for the development of producers of fish products, but also for protecting the ecology of our country. This article discusses one of these technologies, which is based on the integrated processing of collagen-containing fish raw materials. The paper presents statistical data on the catch of aquatic biological resources in different countries. An analysis of fish objects with the highest catch in the region’s waters, as well as those often processed by enterprises of the Kaliningrad region, is presented. The use of secondary fish waste, namely the integumentary tissues of fish formed during filleting and processing of objects into minced fish, has been justified. The chemical composition of the integumentary tissues of pike perch, cod, and pollock has been assessed. These types of fish are actively caught and/or processed in the Kaliningrad region. A technological scheme for the production of protein and proteinmineral additives by enzymatic hydrolysis has been proposed. The chemical composition of the obtained fermentolysates (protein supplements) has been assessed. Organoleptic characteristics have been described. The results of the study indicate the high potential of fish integumentary tissues and the possibility of their processing to produce new food systems using the enzymatic hydrolysis method.

Hot smoked fish is a popular and highly nutritious food product. However, traditional smoking causes the ingress of high molecular weight products of wood pyrolysis – polycyclic aromatic hydrocarbons, including benz(a)pyrene. The Department of Food Biotechnology of KSTU has developed a technology of smokeless smoking of fish by treating it with smoked algae composition based on the extract of red algae of the Baltic Sea Furcellaria lumbricalis and smoking flavoring "Liquid Smoke". The study of the organoleptic quality indicators of experimental and control samples of smoked mackerel, cooked according to the developed and traditional technology, showed their compliance with the requirements of GOST 7447-2015. But smokeless smoked mackerel had more pronounced color and surface shine, there was an enriched aroma of smoked meat. Comparative dynamics of changes in the content of protein, non-protein nitrogen, volatile base nitrogen and amine nitrogen in mackerel samples has been studied. Increased preservation of protein components and decrease of their hydrolysis intensity in smokeless smoking products have been shown. The method of highperformance liquid chromatography confirmed the safety of benz(a)pyrene content (0.0001 mg/kg with the permissible norm of 0.005). The method of atomic absorption spectrophotometry proved safe level of lead (0,21 mg/kg), arsenic (1,1 mg/kg), cadmium (0,032 mg/kg), mercury (0,12 mg/kg). In the studies of microbiological indicators, prolonged shelf life and storage of smokeless smoked mackerel relative to traditional products has been established. Recommended shelf life is 7 days, storage period - 10 days at temperatures from –2 °С to +6 °С. Organoleptic appeal, increased safety and storability of the developed products are due to the factors of technology and the presence of additional functional compounds with coloring, flavoring and preserving properties (carotenoids, flavonoids, anthocyanins, organic acids, carrageenan’s and others) in the composition of smoked algae composition.

This article discusses the hydrodynamics of the catamaran model. The catamaran model is based on the theory of multiphysical similarity. A full scale catamaran consists of two motorboats of the "Wyatboat-430" type, connected with a specially made deck. Boats "Wyatboat-430" are used for coastal fishing, as well as in inland waters, conducting scientific studies of aquatic life stocks in reservoirs of the Russian Federation. For the physical determination of the hydrodynamic resistance of full-scale motor boats "Wyatboat-430" and the catamaran itself, experimental studies have been conducted in the experimental pool of the Federal State Educational Institution "KSTU". The hydrodynamic resistance of a catamaran depends on many characteristics: shape of the hull, roughness of the hull surface, in particular the bottom of the boats, size of the boats, towing speed, distance between the boats (attachment), etc. During the physical experiment, the hydrodynamic resistance has been calculated based on the results of running a catamaran model in the experimental pool of KSTU. The catamaran models are made of fiberglass. Numerical experiments on the calculation of the hydrodynamics of "Wyatboat-430" motorboat have been performed using simulation modeling. A 3D model of the boat "Wyatboat-430" boat has been created to calculate the resistance, using a special Blender program. Calculation of the resistance of the catamaran 3D model has been performed in the Maxsurf Resistance program. This program calculates the approximate hydro-dynamic resistance. After the results obtained, the analysis, comparison and prediction of the hydrodynamic resistance of the catamaran model have been carried out.

The strength problem of the traction motor bolted fastening is investigated when it is placed sideways on the tram car bogie. Such arrangement creates unfavorable conditions for the bolts to perceive the acting loads, which requires a detailed consideration of the bolts stress state. Geometrical models of traction motor and adjoining bogie fragments have been constructed, as well as an assembly based on them in order to study their joint strain by an external load. The preparation of the computational model also includes the finite element discretization, setting the material properties and ways of fixing components. To describe the interaction between traction motor and the bogie supporting surfaces, the conditions of one-way contact have been used; the presence of fasteners is simulated by means of connectors provided for this purpose, with indicating the bolts geometric parameters and the preload value, which allows simulating the operating conditions of bolted connections. The numerical analysis of the model under the constant and variable loads application has been done. In this case, the constant load on the bolts is due to their pretension and the traction motor weight; the variable load is caused by the dynamics of the bogie movement along the rail track, when significant accelerations are possible. Based on the obtained force factors values in the connectors, the stress state parameters of the fastening bolts has been calculated. It has been discovered that the bolt of fastening the traction motor to the lower horizontal support, at a distance from the gravity center, is the most stressed. It has been shown that under operational conditions there is a risk of the bolts breakdown due to noncompliance with strength requirements. Based on the study results, the activities to reduce the negative external loads effect on the fasteners working conditions have been proposed.