Field measurements conducted in the coastal zone of the Russian sector of the Baltic Sea south-eastern part from April 2008 to April 2009 allowed to describe patterns of seasonal distribution of the chlorophyll a concentration (Chl) and primary production (PP) of phytoplankton in the water column under environmental conditions. It is shown that the vertical distribution of Chl is determined by its concentration in the surface layer and hydrophysical conditions, while the vertical distribution of PP performs a decreasing function of depth and light. In late spring-early summer, when the growth of phytoplankton is limited by nutrients, the subsurface maximum of Chl can be observed; as a result, contribution of this layer to the integral PP increases. Indicators of phytoplankton productivity in the coastal zone have been calculated depending on the trophic state of waters (oligotrophic, mesotrophic, eutrophic). Significant variations of Chl (1.2-19.8 mg·m^-3) and PP (40-2153 mgC·m^-2·day^-1) values are observed from the oligotrophic level in the winter period (December-March) to eutrophic level in spring (April) and summer during maximum phytoplankton growth. The analysis has been conducted of the well-known algorithms for calculating PP, proposed for the Baltic Sea, including the equations for detecting the dependence of photosynthesis on the light, presented by J. Still, T. Platt, and A. Jassby-T. Platt. Тhe equations of T. Platt and A. Yassby-T. Platt provided a better correspondence of the PP values calculated for different depths to the data of field measurements of PP at these depths, and J. Still's equation better reproduced the average value of water column PP. 

The paper provides a general description of fishing in the economic zone of Angola and its evolution since 1960. It describes the features of the organization of fishing in the exclusive economic zone of Angola during the period of fishing mainly by USSR and then the formation of national fishing. It is shown that the fishing sector of Angola is of significant importance for the country's economy and accounts for about 4.6% of the country's gross domestic product in 2011. Until the end of the war in 2002, Angola's fishing sector was the third largest economic sector after oil and diamond mining. The total catch reached 500 thousand tons, but due to a decrease in the volume of aquatic biological resources, it decreased. However, it still remains a very important sector for the national economy and an important source of livelihood for the population and food supply for the country. Currently the total catch is estimated in the range of 220–290 thousand tons; the national fleet can provide up to 40 thousand tons. The characteristics of the size composition of the main pelagic fish species and information on the dynamics of their catch on the shelf of Angola are given. The main objects of the fishery are small pelagic species (species of the genera Trachurus, Sardinella, Scomber), as well as dimesal species (Serranidae, Scianidae, Sparidae, Merlucciidae, Pomadasyidae). A characteristic of the types of fishery is given, which include purse seine fishing, bottom and pelagic trawling, as well as artisanal fishery.

Practical activities of research institutes of the Federal Agency for Fishery and other research organizations often involves the necessity to prepare forecasts of a possible national catch for extended time-periods. Different institutions require these forecasts for their business planning and other activities. Generally, accuracy of these deterministic forecasts is low. Moreover, catches of some commercial species are determined by not only biological parameters, but also management decisions that may result in unpredictable consequences. This paper considers the possibility to prepare a long-term forecast of the national catches of commercial species, which depends not only on the state of stocks, but also on economic and political factors. This forecast involves a stochastic-statistical approach that is based on a long-term series of observations over fisheries taking into account some patterns and assumptions. The paper includes analysis of some possible factors that can have a direct impact on sizes of catches and the relation between them. Modelling is based on the Monte-Carlo method and is performed using software designed to assess possible risks when input parameters are uncertain. The result is the most likely scenario for the development of fisheries, indicating the range of forecast uncertainty. As a test example, a long-term forecast for the Russian catch of NA blue whiting (Micromesistius poutassou) up to 2042 was made. For this fish species, the Russian catch sizes may comprise at least 86 000 tons in the long-term. Similar assessments can be made for other commercial species.

The paper presents the results of microbiological studies of poultry offals (chicken feet and heads) and collagen hydrolysate (CH) stored at low temperatures (chilled (4±2 °С) and frozen (minus 18 °С) form). The CH has been studied according to the indicators by which gelled poultry products are evaluated. Safety of raw materials (poultry offals) in accordance with regulatory requirements has been confirmed. Safety of CH in terms of pathogenic and presumptive pathogenic microorganisms has been confirmed as well. The paper also describes a change in the number of mesophilic aerobes and facultative anaerobes in CH in the process of storage. The CH products (HP) have been obtained, namely CH lyophilisate and CH that was dried at 50 °С (DCH). It has been found that the moisture content in the CH is 90.1 ± 0.1%, in the DCH it is 10,7 ± 1,2%, in the lyophilisate it’s 11,1 ± 0,3%. The water activity has been determined: for the CH it is more than 0.95, for the lyophilisate it is 0,36 ± 0,15, for DCH 0,32 ± 0,14. With the use of organoleptic methods it has been found that chilled form of CH has signs of spoilage on the 10th day of storage, and the frozen form has them on 72th day of storage. The strength of CH increased during storage at low temperatures. On the basis of the research, the recommended shelf life for chilled (4±2 °С storage) CH is 7 days, for frozen (minus 18 °С storage) – it’s 60 days. The paper also presents a variant of HP use as an additive to sause. The dosage of 2% HP in the sauce produces a jelly, which confirms the gelling agent properties of the HP.

The paper presents data on change of chemical composition, content of deproteinized shell and output of mince and shell-containing wastes at press-separation of Antarctic krill depending on degree of pressing of belt of perforated drum of pressseparator with diameter of holes 3 mm. Taking into account the obtained data, the necessary condition for sequential use of two press separators with different diameters of holes of the working drum for mince production with acceptable qualitative parameters has been revealed. Change of formol-titrated nitrogen and non-protein nitrogen content during preliminary enzymatic hydrolysis of biological liquid isolated from whole crude krill during centrifugation is shown. Chemical composition of biological fluid (juice) formed during centrifugation has been investigated. A clear dependence of the use of krill mince on the production of molded, culinary products or stuffed products has been  determined, depending on the water-holding capacity. The use of additives made it possible to slow down the hydrolysis of krill mince lipids, which was expressed in lowervalues of the acid number throughout the shelf life. Preliminary enzymatic treatment made it possible to increase the yield of the lipid fraction by more than 20% and intensify the process of destruction of protein substances. The paper also shows a change in the quality of krill mince during refrigeration storage using vacuum packaging and stabilizing additives. Maintaining water-retaining capacity above 60% for 120 days when using food additives will expand the range of products relative to mince without using additives. Introduction of food additives in a certain amount from the mass of krill mince makes it possible to slow down dynamics of decrease of quality indices of krill mince during refrigeration storage.

A method is proposed for processing fish skin with scales in order to obtain food additives and drinks enriched with collagen and its hydrolysis products. It has been determined that as a result of thermal hydrolysis (100 deg C for 2 minutes) fish scales in apple juice (mass fraction of protein – 0.1%, carbohydrates – 11.8%, ash – 0.46%, phosphorus – 0.11%, calcium – traces) and subsequent fractionation of the mixture, the resulting juice drink enriched with collagen hydrolysis products has the following chemical composition: protein – 1.12%, carbohydrates – 10.7%, ash – 0.69%, phosphorus – 0.18%, calcium – 0.02%. Partially hydrolyzed, swollen and crushed in apple juice (ratio 1:3 by weight, duration of hydrolysis – 48 hours at 4 deg C) fish skin (semi-finished product) was mixed and homogenized at a ratio of 1:5 with apple-pear juice, acquiring puree-like consistency with protein content: 1.86%, carbohydrates – 8.2%, ash – 0.54%, phosphorus – 0.26%, calcium – 0.01%. Microbiological tests of fruit juices, skin and scales of pike perch showed compliance with the standardized indicators. Samples of apple-pear juice had the highest microbiological stability during cold storage. Composition of the microflora of fruit juices was formed by spore and non-spore rod-shaped bacteria, at the final stages of storage – yeast and mold fungi, microflora of the skin and scales – coccal bacteria. Indicators of bacterial contamination of samples of fortified drinks, semi-finished products, puree based on apple juice and experimental mixed samples with the addition of orange juice at the background points were insignificant (on average, 8.2 × 10² CFU / cm³), by the end of the shelf life, they naturally increased. The microflora of samples of enriched drinks was formed by non-spore sticks of Pseudomonas putida, Bacillus subtilis alone; in samples with lower pH values, acid-fast bacteria Streptococcus sp., Micrococcus candidus dominated.

Despite of the hunting permission and partial processing of their meat by private farms for sausages or other meat products, the number of animals is growing rapidly, and at the same time the amount of waste after meat processing that has nutritional value is increasing. The present study provides a rationale for the technology of applying an enzyme to the tail to simplify separation of the skin from the lipoprotein part. The optimal concentration of the enzyme, the fermenting time, temperature and duration of heat treatment have been analyzed as well. The enzyme application effect together with such catalysts as citric acid and salt on the beaver tails, resulted in weight, skin thickness and density change. The amount of dry solids passing into the solution after treatment has been also taken into account. During the experiment, it has been found that all fermented samples gain weight by 23% from the initial one. According to the results, the most successful patterns are the samples that get 4 points using citric acid and 0.1% enzyme solution and the sample that get 5 points with a high concentration of the enzyme 0.55 % and two catalysts. The experiment showed that an enzyme-treated tail samples, combined with heat treatment, gave a good result and greatly simplified the separation of inedible skin from the fatty part of the tail.

Implementation of a unique method for producing marine placental collagen in the pilot operation conditions required a serious analysis of methods for assessing the parameters of individual technological stages. The main processes determining the quality of the finished product are separation of water-, salt- and alkali-soluble proteins in combination with the removal of lipids. To control the manufacturing process in the framework of in-process monitoring, it has been proposed to use an assessment of the dynamics of protein accumulation in extractants and the residual lipid content in the collagen. The analysis of standardized methods for determining the mass fractions of protein and fat used in food and pharmaceutical industries has shown a theoretical possibility of using the colorimetric method with a biuretic reagent and the gravimetric modified Soxhlet method, respectively, for technological purposes. Measurement of the protein content allowed for justification of a method for determining the duration of the extraction process under specific temperature conditions. The necessary and sufficient conditions are formulated as boundary factors in determining of this parameter. It has been proposed to consider the residual amounts of non-collagen proteins in the finished product as a technically difficult-to-remove impurity. The appliance of a widely used procedure for the quantitative determination of lipids with modern laboratory equipment suitable for production laboratories equipping, together with the analysis of other available standardized procedures, revealed a problem associated with the lack of an acceptable method due to the content of the measured component in the analyzed matrix at a level below reliable results. As a solution, it has been proposed to fix the value of remaining lipid content in product specification at the level of twice the repeatability limit of the most accurate available measurement procedure.

The article analyzes the shape of the imprint and the nature of the pressure distribution over the contact patch from the wheels on rolling ships, required by the Rules of the Russian River Register (RRR). It has been found that the rectangular shape of the contact patch from the wheel prescribed by the RRR in most cases corresponds to real conditions. Distribution of uniform pressures along the length of the imprint of the wheel does not correspond to the actual picture, but in the direction of the width it is permissible. A formula is presented that describes a certain parabolic function and displays the form of non-uniform pressure along the contact patch. Using the specialized software complex FEMAP with NX NASTRAN, the finite element method was used to assess the stress-strain state of the floors of two trailer ships from the impact of the wheels of a truck and a car. The calculation was carried out taking into account two types of loads: with a uniform and parabolic nature of the pressure distribution along the contact patch. The peak value of the pressure with a parabolic shape turned out to be 1.5 times higher than with a uniform one. The difference in the results of the strength analysis for the maximum displacements and stresses in the beams was about 3%. At the same time, the highest stress values in the flooring, with different forms of pressure distribution over the wheel imprint, differ by 10–11%. The use of the proposed formula, which describes the parabolic nature of the load along the length of the contact patch, can be essential in determining the dimensions of the wheel imprint, the value of the maximum stress in the flooring, and the value of the admissible residual deflection of the flooring, in accordance with the requirements of the RRR Rules.

The paper presents a method and calculation of the cyclic fuel delivery, plunger pairs of high-pressure pumps and nozzle holes of fuel oil atomizers for low-speed marine two-stroke diesel MAN B&W engines with a cylinder capacity from 1310 to 4880 kW. It is shown that for the given power range of marine diesel engines, cyclic delivery at the nominal mode varies from 31 to 188 cm³ , a plunger diameter – from 44 to 80 mm, and holes diameter- from 0.58 to 1.1 mm. It has been found that for MAN B&W 6S50MC diesel engine, with a constant cyclic fuel supply by one nozzle (18500 mm³) at injection duration (0.039 s), an increase in the average pressure in front of the nozzle holes from 30 to 100 MPa makes it possible to reduce the nozzle holes diameter from 0.75 to 0.55 mm, while reducing the average diameter of the sprayed fuel from 49 to 36 microns. Calculations have been performed of the fuel flame, the length of which depends on the nozzle hole diameter; of the speed and time of the fuel expiration, of the density and Weber criteria. Its self-ignition delay period has been found. It depends on the pressure and temperature of the air in the combustion chamber, the average speed of the piston and the excess air coefficient. It is proposed that the time the fuel flame travels from the nozzle opening to the wall of the combustion chamber should be coordinated and approximately equal to the delay time of the fuel selfignition. The proposed method of calculating fuel delivery, a plunger pair of the highpressure pump, nozzle holes diameter of the nozzle sprayer, fuel atomization fineness, a fuel flame length, and a delay period of self-ignition can be useful in improving and developing new designs of the fuel equipment of marine diesel engines