This contribution is the outcome of a field-based observation occurred in the shallow waters of the Asterousia Biosphere Reserve on the southern coast of Creete Island. The occurrence of two IAS highlighted and confirmed the presence of Lessepsian immigrants in the area.

EMB Future Science Brief No. 10 highlights the most recent science on Ocean oxygen, including causes, impacts and mitigation strategies of Ocean oxygen loss, and discusses whether “every second breath we take comes from the Ocean”. It closes with key policy, management and research recommendations to address Ocean deoxygenation and communicate more accurately about the role of the Ocean in Earth’s oxygen. The sentence “every second breath you take comes from the Ocean” is commonly used in Ocean Literacy and science communication to highlight the importance of Ocean oxygen. However, despite its widespread use, it is often not phrased correctly. In contrast, there is little awareness about the threat of the global oxygen loss in the Ocean, called deoxygenation, particularly in comparison with other important stressors, such as Ocean acidification or increasing seawater temperatures. Deoxygenation is increasing in the coastal and open Ocean, primarily due to human-induced global warming and nutrient run-off from land, and projections show that the Ocean will continue losing oxygen as global warming continues. The consequences of oxygen loss in the Ocean are extensive and include decreased biodiversity, shifts in species distributions, displacement or reduction in fisheries resources, changes in biogeochemical cycling and mass mortalities. Low oxygen conditions also drive other chemical processes which produce greenhouse gases, toxic compounds and further degrade water quality. The degraded water quality directly affects marine ecosystems, but also indirectly impacts ecosystem services supporting local communities, regional economies and tourism. Although there are still gaps in our knowledge, we know enough to be very concerned about the consequences: the impacts might even be larger than from Ocean acidification or heat waves, and three out of the five global mass extinctions were linked to Ocean deoxygenation. The sense of urgency to improve Ocean health is reflected in the UN Decade of Ocean Science for Sustainable Development (Ocean Decade) and the EU Mission: Restore our Ocean and Waters (Mission Ocean), and tackling the loss of oxygen in the Ocean is critical to achieving the aims of these two initiatives.

Climate change and biodiversity loss are two of humanity’s greatest challenges. Blue carbon, i.e. the carbon captured and stored by marine living organisms and ecosystems, has the potential to help mitigate both challenges, because marine ecosystems that are important for sequestering carbon often also harbour rich biodiversity. Expanding and protecting Blue Carbon ecosystems has therefore been proposed as a Nature-based Solution to complement climate change mitigation efforts on land and to protect and restore marine biodiversity. In addition, securing and rebuilding Blue Carbon ecosystems can stabilise livelihoods, protect coasts, and support other societal needs such as food provision from the Ocean. However, the effectiveness of Blue Carbon ecosystems as a Nature-based Solution depends on the available space and ecosystem productivity, which can be impacted by climate change. Moreover, the overall carbon sequestration potential of Blue Carbon ecosystems is low and their contribution to climate stabilisation will only be significant once greenhouse gas emissions are strongly limited. Therefore, a drastic reduction of greenhouse gas emissions to keep global warming close to 1.5°C above pre-industrial levels is essential to maintain the health and long-term functionality of Blue Carbon ecosystems as a Nature-based Solution. This document describes examples and benefits of Blue Carbon ecosystems, and discusses uncertainties and challenges for the conservation and restoration of Blue Carbon ecosystems as a climate change solution. It also highlights the wider role of the Ocean in mitigating climate change through the carbon cycle, and closes with key research and management recommendations.

A model for optimal planning of fishing activities has been proposed. It includes the formation of a biological component (a set of fishing objects considered taking into account their distribution over fishing zones) and a technological component (a set of fishing vessels and fishing technologies). On the basis of these two components, the technological chain "field object – production vessel – production technology" is formed. For each type of fishing vessel, it is permissible to use a certain type (or several types) of fishing technologies that are directly related to fishing objects, their catch can be carried out only using a certain production technology. Particular attention in the model is given to the problem of determining the optimal quantitative composition of the production fleet. The optimization criterion is the minimization of the costs associated with the fishing activities of specialized vessels, provided that the specified volumes of catch are achieved. The costs are directly related to the types of vessels used, fuel costs depending on the vessel's home port and the time required for loading and unloading operations. In the optimization problem, estimates of the weighted average daily catch and fishing time are used to account for most of the costs associated with the extraction of aquatic biological resources. The optimization algorithm is considered on the example of the Commander squid (Berryteuthis magister) in the North Kuril zone. In the area under consideration, squid production is carried out using trawl technology. The main types of vessels engaged in squid harvesting are large-capacity and medium-capacity vessels.

The development of fish oil production in Russia requires solving a number of environmental issues. It is necessary to develop technologies for processing low-grade semi-finished products of fish oils and fat waste. Currently, this problem remains unresolved. In the course of the study, the physicochemical properties of fat-containing objects (semi-finished product of technical fish oil with acid number of more than 20 units; soap stock after fish oil refining; fatty foam mass after flotation treatment of industrial wastewater from fish oil production) have been determined and rational directions for their use have been established. It is noted that these objects contain lipids with a high degree of hydrolysis and unsaturation. The developed methodology for creating private technologies for processing technical fish oils and fatty wastes into target products for technical purposes makes it possible to obtain an oil-in-water dispersed system and a fatty acid concentrate from the objects of study. The resulting products can be used as a basis for the production of anti-adhesive, surface-active, film-forming and anti-friction technical reagents for various industries (including food industry).

The paper analyzes the effect of using fermented minced fish (FMF) with the L. plantarum probiotic in the formulation of dry-cured sausages on the quality characteristics of the finished product in comparison with sausages based on unprocessed minced fish. The microbiological, physico-chemical, structural-mechanical and organoleptic properties of the product have been evaluated. The results have shown that dry-cured sausage samples with FMF had a higher content of probiotics (2,5×108 CFU/g) compared to the control sample (6,3×106 CFU/g), which allows a person to fully meet the daily requirement in probiotics with just through the use of 40 g of such a product. The use of FMF in the dry-cured fish sausages provides a safe pH value (5.21) and significant increase in total acidity (1.39 %) compared to the control sample (pH – 6.80 and total acidity – 0.45 %). It has been established that using FMF in the technology of dry-cured fish sausages can reduce the time of their manufacture by increasing the average rate of dehydration of the product. It has been determined that samples of dry-cured sausages with FMF have higher values of hardness and cutting force. A comprehensive assessment of the quality of sausages with FMF has shown good results – 76.85 % of the maximum possible level. Thus, the possibility of using FMF with L. plantarum in the manufacture of dry-cured sausages has been determined. The proposed method makes it possible to obtain a product with a high protein content (32.31 %), enriched with L. plantarum probiotics, having a low pH value and a peculiar sour-milk taste and aroma. Based on the results of the study, normative and technical documentation for this type of product has been developed and approved.

Based on the available biological and fisheries data, stock status review for 18 units of the fish species inhabiting the Black Sea and the both Azov and Black Seas is presented. A modified version of the traditional approach to the harvest control rules for the aquatic bioresources of the Azov and Black Sea Fishery Basin is described for the case when they are assessed by the mathematical methods to estimate the current stock biomass and fishing mortality. For 11 stock units, analytical modeling including cohort, production and trend models has been applied. Based on the estimates of biomass and fishing mortality concerning biological reference points, in 2021, the status of six stock units of the marine fish species inhabiting the basin and exploited by the Russian fisheries was identified as increasing or stable (“Black Sea” stock units of the European sprat and European anchovy, “Crimean” stock unit of turbot, “Crimean and Caucasian” stock unit of red mullet, and “Black and Azov Seas” stock units of garfish and rays). Five fishery stock units (“Crimean and Caucasian” of mullets, picarel and Mediterranean horse mackerel, “Black and Azov Seas” of sand smelts, and “Caucasian” of turbot) have shown a decreasing trend in terms of abundance, and for the rest of the investigated fish stock units (“Mediterranean migrant” bluefish, Atlantic bonito and Atlantic mackerel, “Black Sea” whiting, so-iuy mullet and the other marine fish species, “Black and Azov Seas” spiny dogfish), the status has not been determined due to the absence of systematic biological and fishery data.

The study conducted in 2022 has identified a lack of consistency in the results of the beluga artificial reproduction at the Don Sturgeon Hatchery (DSH). To obtain eggs, mostly the females born in 2001–2004 were used, out of which 31 females at age 18 reached their first maturity and one female at age 21 was a repeat spawner. The majority of first-spawning females produced eggs of low quality. During incubation, there was a substantial loss of fertilized eggs, and various anomalies of embryonic development were observed, which necessitated termination of the incubation of such eggs. The yield of one-day larvae from the eggs obtained from the first-spawning females and set for incubation was low, around 12 %. One of the reasons for the increased mortality rates and development anomalies in the larvae was low quality of the oocytes in the first-spawning individuals. A second-spawning female has shown satisfactory results; the fertilization rate was in line with the standard values, and no more than 17 % of the eggs manifested embryonic anomalies during their incubation. The yield of one-day larvae was 53.3 %. In total, 799 thousand one-day beluga larvae were obtained. The analysis of the cultivation practices at the Don Sturgeon Hatchery made it possible to identify the bottleneck points and critical junctures at some stages of the biotechnological process, as well as to give recommendations on improvement of the hatchery operation. An important prerequisite for obtaining good results is the physiological adequacy of beluga females, which is based, for the most part, on the living environment and feeding quality of the breeders and their replacement in the broodstock.

Numerous scientific publications are dedicated to the analysis of long-term variability of zooplankton biomass in oceanic and neritic zones of the World Ocean. The number of these publications keeps growing with the availability of new data. Relevance of this research can be attributed to the crucial role of zooplankton biomass in the spatio-temporal and trophic structure of aquatic ecosystems. Interannual fluctuations of zooplankton biomass affect the catch volumes of small pelagic fish. This research is aimed at identification of statistically valid long-term trends of the World Ocean zooplankton biomass, which involves the analysis of the data from databases and published articles describing such variability. Regional and international databases (namely COPEPOD, HOT, JGOFS, ODATE and others), which are available in the form of CDs, archived materials, and online, have been used. For the time series of the biomass across 21 areas of the World Ocean (Pacific, Indian, Atlantic Oceans and internal seas), the regression analysis has been conducted, which made it possible to estimate the parameters of linear monotonic trends. Based on bivariate spatial autocorrelation functions, the areas within which the trends are statistically homogeneous have been identified. A comparative study of long-term variability of zooplankton biomass, phytoplankton biomass, primary production, and the total live biomass of the pelagic World Ocean is presented. It is shown that the spatial distribution of positive, negative and neutral trends of zooplankton biomass on the World Ocean scale is heterogeneous. The negative monotonic trends of zooplankton biomass are found to be prevailing (in 1980–2010s); the regression parameters describing them are presented.