Marine ecosystems are becoming increasingly vulnerable to cumulative anthropogenic effects and pressures. Therefore, various methodological approaches and tools have been designed to apply cumulative impact appraisal schemes and better assess the dynamics and interactions among pressures affecting marine ecosystems. This study aims to apply the Spatial Cumulative Assessment of Impact Risk for Management (SCAIRM) tool for the Black Sea coastal waters considering human activities, pressures, and effects on different ecosystem components coupled with one management scenario development for actual and new emerging sectors. According to the SCAIRM, the primary pressure on the marine ecosystem was identified as introducing or spreading non-indigenous species from shipping. Additionally, when considering cumulative impact, activities related to coastal defense and flood protection, particularly beach nourishment works, were found to have the highest impact. This is due to the cumulative scores associated with the physical loss from permanent alteration or removal of seabed substrates, and temporary or reversible physical disturbances to the seabed. The scenario development indicated that after shipping, oil and gas exploitation is anticipated to become the second-highest risk sector for additional impact in the Romanian Black Sea. Additionally, the increased military activities related to the war in Ukraine present escalating risks that must be considered in EBM strategies. The results assess the possible effects of human activities and the associated pressures to direct management toward achieving sustainability, biodiversity protection, and the marine ecosystem’s integrity.

The Black Sea Rapa whelk (Rapana venosa, Valenciennes 1846) is, on one hand, a non-indigenous species harming Black Sea benthic ecosystem and on the other hand, since its ever-epanding stock found market in the Far East, one of the most profitable in the basin. For this purpose, the Working Group on the Black Sea (WGBS) under General Fisheries Commission for Mediterranean and Black Sea (GFCM) agreed on the fact that, despite the invasive nature of the species, its stock in the Black Sea should be eploited within biologically safe limits. In order to cover the area of study in high percentage, a number of 51 stations were proposed for Romanian coast, that were distributed evenly. The duration of one haul was 30 minutes and the hauls were performed at a constant depth and rectilinear in a big percentage, but to avoid tangles and gear destruction, some deviations have been made. Age composition in 2020 was formed by 3 to 12 years generations, the percentages were recorded for 6- and 7-years classes. Regarding 2021 data, the age composition was composed by 3 to 11 years, with the numbers recorded for 5- and 6-years classes. Highest abundance and biomass values for rapa whelk in 2020 have been recorded in the north part of the Romanian coast in the sectors Zaton, Sahalin, Sf. Gheorghe and Mila 9. For 2021, data no significant changes were observed.

With the growth of the human population, the need for food resources increases, so the pressure on living marine resources also increases. In addition to this aspect, the Black Sea ecosystem during recent decades suffered changes that determined the deterioration of all components of the marine ecosystem, which had direct impact on decreasing the biological diversity and productivity, affecting the quality of life and ecological balance. The species Alosa immaculata (Bennet, 1835) - Pontic shad is of high commercial value and with an important role in the livelihoods of many local communities across the Black Sea coast. However, the status of Pontic shad fisheries is unknown, mainly because is a status of data-poor fish stocks. Thus, growth parameters were determined in a total of 783 individuals with a biomass of 194.5 kg from 9 fishing points of the Romanian Black Sea Coast. For the estimated parameters of length-weight relation the combined data and sexes have been used, coefficient of determination (r²) was 0.794 and b value 2.879. A negative allometric growth has been observed for the species where b<3. The virtual population analysis (VPA) by lengths was performed using the FISAT II software. Catch data previously determined were used to apply the model: length class frequency set, coefficients a=0.0134 (2021) and b=2.879 (2021) of the length-weight relationship, natural mortality M=1.12/year, L∞=37.8, k=0.87/year. The main aim of this paper is to provide an overview of the current status and trends of this valuable resource.

This study aimed to evaluate the growth, mortality parameters, and exploitation rate of Pontic shad, Alosa immaculata Benett, 1835, in the Danube River, Romania (km 169–197). The sampling collection started with the first signs of Pontic shad migration, on 4 March 2023, and continued weekly until the beginning of June 2023, when the last specimens were caught in the nets. The estimation of the growth, mortality parameters, and exploitation rate was done in FiSAT (FAO-ICLARM Stock Assessment Tools). The von Bertalanffy growth equation was estimated at L_∞ = 36.75 cm, the growth coefficient was k = 0.68 year⁻¹, and the theoretical initial age was t₀ = −0.67 year⁻¹. The total mortality rate (Z) estimated was 2.76 year⁻¹, with a natural mortality rate (M) and fishing mortality rate (F) of 0.89 year⁻¹ and 1.87 year⁻¹, respectively. The Z/k ratio was found to be 4.11 and the exploitation rate (E) was estimated at 0.68 year⁻¹, indicating the overexploitation of Alosa immaculata stocks. In conclusion, this study provides valuable insights into the population dynamics of Pontic shad in the Danube River, Romania. The assessments of the growth parameters, mortality rates, and exploitation rates highlight a level of overexploitation of Alosa immaculata stocks. These findings underscore the importance of applying effective fishery management strategies to ensure the sustainability and conservation of this valuable fish species in the Danube River ecosystem.

Until recently, the smooth scallop Flexopecten glaber (Linnaeus, 1758) was considered absent from Romanian Black Sea waters, as only isolated valves were documented on beaches of the southern coast. Yet, in 2020, the first living specimens were collected by dredging at 25 m depth in Mangalia. Moreover, in the past three years, a considerable number of live individuals were also retrieved from beam-trawling operations targeting the gastropod Rapana venosa (Valenciennes, 1846) along the Romanian coast, indicating that there is a stable population here. This remarkable expansion of F. glaber in Romanian waters may be explained as a consequence of the Black Sea’s recovery from eutrophication, reduced predatory pressure from the declining population of R. venosa and changing climate conditions. Our research aimed at using all this novel information to document for the first time the occurrence and distribution of this bivalve on the Romanian coast, also considering perspectives for the development of a new type of shellfish mariculture, avoiding any pressure on the natural stock. In total, 386 F. glaber individuals were sampled during 2020–2023, at depths between 22.5 and 33.3 m. The abundance and biomass per station oscillated between 5 and 319 specimens and 51.5 and 7377 g, respectively. A subsample of 122 specimens was preserved and analyzed in the laboratory, revealing an average shell length of 53.54 mm (±4.13 SD) and an average shell height of 49.54 mm (±3.64 SD). The smooth scallop has both ecological and economic value, which makes it a viable candidate for sustainable aquaculture by collecting spat from the most abundant areas and subsequently placing “seedlings” in the appropriate polygons for stock recovery. Ultimately, commercial exploitation from aquaculture installations can be considered, provided a permanent healthy F. glaber population is established on the Romanian coast.

Sex ratio, morphometric characteristics, age and growth for Pontic shad from Romanian Black Sea Coast were examined. A total of 2.133 individuals were caught between March 2012 and September 2013. Female : male sex ratio was 0.62. According to the age reading, distribution varied form II to V year. The von Bertalanffy equation and growth performance index were determined by ESP software in Pontic shad. The asymptotic length (L∞ = L infinity) of Pontic shad generated by the ELEFAN I method, after introducing total length data for the two years of study, was 41.5. The natural mortality instantaneous coefficient (M) of the entire Pontic shad population, calculated according to Pauly’s empirical equation, using the growth parameters of the Von Bertalanffy formula and the mean annual temperature of the two study years of 13°C, recorded the following values: M = 0.585 in 2012 and M = 0.639 in 2013. According with the resultants, it is recommended to perform a sustainable fishing which allows the capture of legal-sized of fish.