Viral metagenomic survey of Caspian seals.

Introduction: Viral diseases of pinnipeds cause substantial mortality and morbidity and can influence population demography. Viral metagenomic studies can therefore play an important role in pinniped health assessments and disease surveillance relevant to both individual species and in a "One Health" context. Methods: This study used a metagenomic approach with high throughput sequencing to make the first assessment of viral diversity in Caspian seals (Pusa caspica), the only marine mammal species endemic to the Caspian Sea. Results: Sequencing libraries from 35 seals sampled 2009-2020 were analysed, finding sequences from the viral families Circoviridae, Parvoviridae, Herpesviridae, Papillomaviridae, Picornaviridae, Caliciviridae, Cruciviridae, Anelloviridae, Smacoviridae, and Orthomyxoviridae, with additional detection of Adenoviridae via PCR. The similarity of viral contigs from Caspian seal to sequences recovered from other pinnipeds ranged from 63.74% (San Miguel sea lion calicivirus) to 78.79% (Seal anellovirus 4). Discussion: Some findings represent novel viral species, but overall, the viral repertoire of Caspian seals is similar to available viromes from other pinnipeds. Among the sequences recovered were partial contigs for influenza B, representing only the second such molecular identification in marine mammals. This work provides a foundation for further studies of viral communities in Caspian seals, the diversity of viromes in pinnipeds more generally, and contributes data relevant for disease risk assessments in marine mammals.

Potential use of gammarus (Pontogammarus maeoticus) and shrimp (Palaemon elegans) as biomonitors of microplastics pollution in coastal environments.

Microplastics (MPs) pose a significant threat to marine ecosystems, necessitating robust biomonitoring to assess aquatic risks and inform effective policymaking. In this study we investigated MPs pollution in gammarus (Pontogammarus maeoticus), shrimp (Palaemon elegans), sediment and water samples of southern coast of the Caspian Sea to assess the potential use of these two crustaceans as biomonitors of MPs pollution, bioconcentration of MPs in organisms' tissue and the pollution risks of MPs in environmental matrices. Samples were collected from 6 stations during June to August 2023. MPs were found in all compartments with an average of 100 ± 45.34 items/kg dry weight, 0.45 ± 0.06 items/L, 0.38 ± 0.21 items/individual or 0.58 ± 0.34 items/g wet weight (ww) and 0.26 ± 0.15 items/individual or 8.69 ± 7.88 items/g ww, for sediments, seawaters, P. elegans and P. maeoticus, respectively. MPs were prevailed by class 300-1000 µm in size, polyamide in polymer, fiber in shape and black in color. P. maeoticus and P. elegans did not meet the selection criteria as MPs biomonitors. However, bioconcentration factor (BCF) illustrated that both crustaceans can absorb and accumulate MPs from their surrounding water (BCF >1). Based on contamination factors (CF) values, sampling stations were polluted with MPs (1 ≤ CF < 6). The overall pollution load index (PLI) for sediment and seawater stations were 2.47 and 1.88, respectively, indicating minor contamination with MPs in the risk level I. Current research provides useful information on MPs pollution in crustaceans species and the risk level of MPs in environmental matrices that can be suitable for bioaccumulation hazard assessment and future monitoring programs.

The importance of temporal scale in distribution modeling of migratory Caspian Kutum, Rutilus frisii.

The choice of temporal resolution has high importance in ecological modeling, which can greatly affect the identification of the main drivers of an organism's distribution, considering the spatiotemporal dynamism of environmental predictors as well as organisms' abundance. The present study aimed to identify the spatiotemporal distribution patterns of Caspian Kutum, Rutilus frisii, along the southern coast of the Caspian Sea, north of Iran, evaluating multiple temporal resolutions of data. The boosted regression trees (BRT) method was used to model fish catch distribution using a set of environmental predictors. Three temporal scales of data, including seasonal, sub-seasonal, and monthly time frames over the catch season (October-April), were considered in our modeling analyses. The monthly models, utilizing more detailed data scales, exhibited the highest potential in identifying the overall distribution patterns of the fish, compared to temporally-coarse BRT models. The best models were the BRTs fitted using data from March and April, which represented the final months of the catch season with the highest catch levels. In the monthly models, the main determinants of the Kutum's aggregation points were found to be dynamic variables including sea surface temperature, particulate organic and inorganic carbon, as opposed to static topographic parameters such as distance to river inlets. Seasonal and sub-seasonal models identified particulate inorganic matter and distance to river inlets as the predictors with the highest influence on fish distribution. The geographical distributions of fish biomass hotspots revealed the presence of a stable number of fish aggregation hotspot points along the eastern coast, while some cold-spot points were identified along the central and western coasts of the Caspian Sea. Our findings indicate that utilizing fine time scales in modeling analyses can result in a more reliable explanation and prediction of fish distribution dynamics. The investigated approach allows for the identification of intra-seasonal fluctuations in environmental conditions, particularly dynamic parameters, and their relationship with fish aggregation.

Durvalumab plus platinum-etoposide chemotherapy for extensive-stage small cell lung cancer: a retrospective real-world study.

Background: Immune checkpoint inhibitor plus platinum-etoposide (PE) improved overall survival (OS) in patients with extensive-stage small cell lung cancer (ES-SCLC). While the CASPIAN trial demonstrated the efficacy of durvalumab plus PE, the clinical trial results may not be representative of the general, real-world population because clinical trials often have strict inclusion and exclusion criteria. We herein report the efficacy and safety of durvalumab plus PE in patients with ES-SCLC in real-world, clinical practice. Methods: The present, monocentric, retrospective study evaluated patients with ES-SCLC or recurrent, limited-stage SCLC who received durvalumab plus PE between September 2020 and February 2023. The efficacy and incidence of adverse events (AEs) were also evaluated. Results: The study included 40 patients, of whom 17 were elderly (age >70 years), and 15 had performance status (PS) 2 or 3. The median follow-up time was 13.0 months [95% confidence interval (CI): 8.0-22.2 months]. The objective response rate was 80.0% (95% CI: 63.1-91.6%), and the disease control rate was 88.6% (95% CI: 73.3-96.8%). The median progression-free survival (PFS) was 5.9 months (95% CI: 4.9-6.9), and the median OS was 25.4 months (95% CI: 4.6-46.2). Factors such as advanced age, poor PS, and presence of brain metastases were not associated with lower PFS and OS. Twenty-six patients (65.0%) experienced grade 3 or higher AEs, mainly hematological toxicity. AEs leading to treatment discontinuation occurred in three patients (8%). Conclusions: Durvalumab plus PE in patients with ES-SCLC showed good efficacy and safety according to our real-world data, suggesting that this treatment is well tolerated in clinical practice, even in elderly patients and those with poor PS.

Brief Report: Real-World Eligibility for Clinical Trials in Patients With Extensive-Stage SCLC at a Tertiary Care Center.

Introduction: The CASPIAN and IMpower133 trials revealed a significant survival benefit of chemotherapy plus immunotherapy in patients with extensive-stage SCLC. The current study characterizes the proportion of real-world patients who would have met eligibility for these trials and highlights factors influencing eligibility in the real-world setting. Methods: A retrospective analysis of patient data was conducted for stage IV patients with SCLC treated at the Cancer Centre of Southeastern Ontario, Canada. Trial eligibility was based on criteria used in the IMpower133 and CASPIAN trials. Data were summarized using descriptive statistics. Overall survival was assessed using the Kaplan-Meier method. Results: Of the 116 patients included, only 12.1% met the overall eligibility criteria for the IMpower133 trial, and 14.7% for the CASPIAN trial. The most common reasons for ineligibility included: Eastern Cooperative Oncology Group (ECOG) 2 or greater (77.5%), inadequate organ function (48%), and the presence of brain metastases at diagnosis (37.3%). Sixty-one patients (59.8%) met two or more major ineligibility criteria. If trial eligibility was expanded to include ECOG 2 patients, an additional 10.3% would have met eligibility. The median overall survival for all-comers was 6.5 months. Conclusions: Only a small minority of real-world patients with extensive-stage SCLC would have met eligibility for the IMpower133 and CASPIAN trials, with ECOG greater than or equal to 2, inadequate organ function, and brain metastases comprising the most common reasons for trial ineligibility. Future clinical trials should expand the inclusion criteria to better represent real-world patient populations.

Determination of Anthropogenic Pollutants in Adipose Tissue of the Caspian Seal Pusa caspica Gmelin, 1788 by High-Resolution Accurate Mass Spectrometry.

Tissue contamination with persistent organic pollutants (POPs) in organisms proved possible to comprehensively characterize in a single test by combining gas chromatography and high-resolution accurate mass spectrometry. Adipose tissue samples were collected from two Caspian seals (Pusa caspica Gmelin, 1788) found dead on the Caspian Sea shore in 2020. Organochlorine pesticides, primarily DDT and HCH, and polychlorinated biphenyls (PCBs) were major pollutants found in the Caspian seals. The distribution of metabolites indicated the absence of recent pesticide use. The PCB content was relatively high, but still at the lower limit of the range of values determined previously, as was also the case with pesticides. Chlordanes, polychlorinated naphthalenes, and polybrominated diphenyl ethers were detected in minor quantities and were therefore not considered to be major pollutants of the Caspian seal. The pollutant levels were below a threshold at which a distinct effect on seal health can be expected. High-resolution accurate mass (HRAM) spectrometry was found to provide a convenient tool for both targeted and nontargeted analyses of a wide range of organic pollutants in a single experiment.

Pinnipeds and avian influenza: a global timeline and review of research on the impact of highly pathogenic avian influenza on pinniped populations with particular reference to the endangered Caspian seal (Pusa caspica).

This study reviews chronologically the international scientific and health management literature and resources relating to impacts of highly pathogenic avian influenza (HPAI) viruses on pinnipeds in order to reinforce strategies for the conservation of the endangered Caspian seal (Pusa caspica), currently under threat from the HPAI H5N1 subtype transmitted from infected avifauna which share its haul-out habitats. Many cases of mass pinniped deaths globally have occurred from HPAI spill-overs, and are attributed to infected sympatric aquatic avifauna. As the seasonal migrations of Caspian seals provide occasions for contact with viruses from infected migratory aquatic birds in many locations around the Caspian Sea, this poses a great challenge to seal conservation. These are thus critical locations for the surveillance of highly pathogenic influenza A viruses, whose future reassortments may present a pandemic threat to humans.

Complete Mitochondrial Genome of Clupeonella abrau (Maliatsky, 1930) (Clupeiformes), an Endemic Freshwater Fish from the Lake Abrau (Russia).

The Abrau sprat (tyulka or sardelka) Clupeonella abrau (Maliatsky, 1930) is an endemic fish of the Lake Abrau (Krasnodar Krai, Russia). The full C. abrau mitochondrial genome (16 650 bp) showed a gene arrangement conserved in Clupeidae and 98.8% similarity with the mitochondrial genome of the related species Black and Caspian Sea sprat C. cultriventris from the Black Sea. The COX1 gene sequence was additionally studied in a museum specimen collected in the Lake Abrau in 1938. Variability in modern Abrau sprat COX1 gene locus was estimated at approximately 0.15%, the difference between C. abrau and C. cultriventris was 1.2%, and the difference between the museum and modern C. abrau specimens from the Lake Abrau was 0.92%. The study confirmed that the Abrau sprat is present in the fish community and is capable of reproducing in the lake. Various scenarios were proposed to explain colonization of the Lake Abrau by C. abrau.

Assessing Chlorophyll-a Variations in Caspian Sea during the COVID-19 Pandemic.

The COVID-19 pandemic's disruptions to human activities prompted serious environmental changes. Here, we assessed the variations in coastal water quality along the Caspian Sea, with a focus on the Iranian coastline, during the lockdown. Utilizing Chlorophyll-a data from MODIS-AQUA satellite from 2015 to 2023 and Singular Spectrum Analysis for temporal trends, we found a 22% Chlorophyll-a concentration decrease along the coast, from 3.2 to 2.5 mg/m³. Additionally, using a deep learning algorithm known as Long Short-Term Memory Networks, we found that, in the absence of lockdown, the Chlorophyll-a concentration would have been 20% higher during the 2020-2023 period. Furthermore, our spatial analysis revealed that 98% of areas experienced about 18% Chlorophyll-a decline. The identified improvement in coastal water quality presents significant opportunities for policymakers to enact regulations and make local administrative decisions aimed at curbing coastal water pollution, particularly in areas experiencing considerable anthropogenic stress.

Antibiotics in surface waters of the south caspian sea: Occurrence, spatial distribution and ecological risks.

Marine environments play a crucial role in absorbing land-based pollutants. While the presence of pharmaceuticals in various marine settings worldwide is well-documented, there is a lack of data regarding pharmaceutical occurrence in the south Caspian Sea. This study examined the presence and spatial distribution of 14 antibiotics in the surface waters of the south Caspian Sea during summer of 2020. Our findings revealed that antibiotics were widespread in this region, with total concentrations reaching up to 3499.9 ng/L. The detection frequencies of the studied antibiotics ranging from 22.0% to 67.0%. Trimethoprim, ofloxacin, and sulfamethoxazole were commonly detected, with detection frequencies exceeding 56.0%. Ofloxacin (235.8 ng/L) and Erythromycin-H2O (2.3 ng/L) had the highest and lowest detected concentrations among the studied antibiotics. Furthermore, fluoroquinolones exhibited notably higher concentrations compared to other antibiotic groups. The highest concentrations of most antibiotics were found in surface waters collected from Ramsar and Chalus stations, located in the middle section of the coastline. Across all transects, the distribution of antibiotics exhibited a decreasing trend towards the sea, indicating that coastal and inland aquaculture, as well as municipal wastewaters, were probably the primary sources of antibiotics in this area. Multivariate analysis revealed that antibiotics, phosphate, nitrate, and COD were all positively correlated with stations Ram-1, Ram-20, Cha-1, Cha-20, and Tor-1, where the highest antibiotic levels were recorded. Risk assessment indicated that clarithromycin, ofloxacin and enrofloxacin posed medium to high risks to aquatic organisms. These findings offer essential baseline information and valuable insights for the comparative assessment of future antibiotic data in the south Caspian Sea.

Comparison of Real-world Efficacy and Safety of Atezolizumab and Durvalumab in Combination With Chemotherapy for First-line Treatment of Extensive-stage Small-cell Lung Cancer.

BACKGROUND/AIM: The combination of programmed cell death ligand 1 inhibitors and platinum-based chemotherapy has become the standard treatment for first-line therapy in extensive-stage small-cell lung cancer (ES-SCLC). This study compared the efficacy and safety of atezolizumab plus chemotherapy and durvalumab plus chemotherapy in the treatment of ES-SCLC in clinical practice. PATIENTS AND METHODS: We retrospectively analyzed 40 patients with ES-SCLC treated with atezolizumab plus chemotherapy or durvalumab plus platinum-based chemotherapy at the Fukuoka University Hospital between October 2019 and November 2022. RESULTS: Among the 40 patients, 20 were treated with atezolizumab and 20 were treated with durvalumab. There was no significant difference in patient characteristics between the two groups; five patients who received atezolizumab and one who received durvalumab showed a performance status of 2 or higher. The median progression-free survival of patients who received atezolizumab or durvalumab was 5.6 and 5.4 months, respectively (p=0.881). The median overall survival of patients who received atezolizumab or durvalumab was 10.0 and 17.1 months, respectively (p=0.163). The objective response rate of the patients who received atezolizumab or durvalumab was 80.0% and 85.0%, respectively. There was no significant difference in the incidence of immune-related adverse events between the groups. CONCLUSION: This retrospective study was the first to compare the efficacy and safety of PD-L1 antibody, atezolizumab or durvalumab, in combination with carboplatin and etoposide in treatment-naïve ES-SCLC Japanese patients in a real-world setting. Both regimens, atezolizumab or durvalumab with carboplatin and etoposide, were effective and well-tolerated in Japanese ES-SCLC patients, in line with clinical trial findings.

The combined effects of anthropogenic and climate change on river flow alterations in the Southern Caspian Sea Iran.

In recent years, the effects of human activities and climate change on river flow patterns have become a major concern worldwide. This is particularly true in the southern Caspian Sea (SCS) region of Iran, where increasing water-intensive socio-economic development and climate change have significantly altered river flow regimes. To better understand these changes, this study employs two nonparametric methods, the modified Mann-Kendall method (MK3) and Innovative Trend Analysis (ITA), to examine spatial and temporal changes in hydrometeorological variables in the SCS. The study also evaluates the impact of human activities and climate change on river flow alteration using elasticity-based methods and the Budyko hypothesis in 40 rivers on the closest gauges to the Caspian Sea. The results indicate an alarming trend of increasing temperature, potential evapotranspiration, and decreasing river flows in the SCS region. In particular, human activities were found to be responsible for around 91.7 % of the change on average, resulting in a significant decline in inflow to the Caspian Sea by about 3216 MCM annually. This declining trend in inflow could potentially exacerbate the eutrophication conditions in the Sea and negatively impact its ecosystem and economics. Therefore, appropriate measures need to be taken to address these environmental and socio-economic issues in the southern Caspian Sea region.

Origin and comprehensive risk assessment of heavy metals in surface sediments along the Caspian Sea.

Metal concentrations (Cu, Zn, Cr, Fe, As, Pb, Ni, V, and Co) in surface sediments were determined in the southern Caspian Sea. Sediment pollution was investigated using geochemical index such as Enrichment Factor (EF) and ecological risk indices like modified Hazard Quotient (mHQ) and Toxic Risk Index (TRI). The highest calculated geochemical index was observed in sediments near the cities of Chalus and Ramsar, which are highly polluted due to human activities. The ecological potential indices indicated that Ni contents in all the studied stations would impose harmful effects on aquatic organisms, while other metals had a low risk. Principal component and cluster analyses suggested that As and Pb emanated from anthropogenic sources, and other metals probably originated from lithogenic sources.

Size, shape, and elemental composition as predictors of microplastic surface erosion.

The degradation of surfaces and its possible dependence on shape, size, and elemental composition of plastic particles were subjected. The surfaces of 146 microplastics were classified from smooth to fully eroded (%) by SEM/EDS. Structural elements and various additives were found on microplastics depending on their shapes. The surface of plastic items > 100 µm in length showed a relatively more eroded area than smaller ones, regardless of their shapes. Depending on shape, the percentage of surface erosion of irregularly shaped fragments < 100 µm was significantly enhanced compared to microbeads of the same size. These results may provide insights into assessing potential risks posed by microplastics and improve our understanding of the role of these parameters concerning possible adverse health effects on the environment.

Avian Influenza Virus and Avian Paramyxoviruses in Wild Waterfowl of the Western Coast of the Caspian Sea (2017-2020).

The flyways of many different wild waterfowl pass through the Caspian Sea region. The western coast of the middle Caspian Sea is an area with many wetlands, where wintering grounds with large concentrations of birds are located. It is known that wild waterfowl are a natural reservoir of the influenza A virus. In the mid-2000s, in the north of this region, the mass deaths of swans, gulls, and pelicans from high pathogenicity avian influenza virus (HPAIV) were noted. At present, there is still little known about the presence of avian influenza virus (AIVs) and different avian paramyxoviruses (APMVs) in the region's waterfowl bird populations. Here, we report the results of monitoring these viruses in the wild waterfowl of the western coast of the middle Caspian Sea from 2017 to 2020. Samples from 1438 individuals of 26 bird species of 7 orders were collected, from which 21 strains of AIV were isolated, amounting to a 1.46% isolation rate of the total number of samples analyzed (none of these birds exhibited external signs of disease). The following subtypes were determined and whole-genome nucleotide sequences of the isolated strains were obtained: H1N1 (n = 2), H3N8 (n = 8), H4N6 (n = 2), H7N3 (n = 2), H8N4 (n = 1), H10N5 (n = 1), and H12N5 (n = 1). No high pathogenicity influenza virus H5 subtype was detected. Phylogenetic analysis of AIV genomes did not reveal any specific pattern for viruses in the Caspian Sea region, showing that all segments belong to the Eurasian clades of classic avian-like influenza viruses. We also did not find the amino acid substitutions in the polymerase complex (PA, PB1, and PB2) that are critical for the increase in virulence or adaptation to mammals. In total, 23 hemagglutinating viruses not related to influenza A virus were also isolated, of which 15 belonged to avian paramyxoviruses. We were able to sequence 12 avian paramyxoviruses of three species, as follows: Newcastle disease virus (n = 4); Avian paramyxovirus 4 (n = 5); and Avian paramyxovirus 6 (n = 3). In the Russian Federation, the Newcastle disease virus of the VII.1.1 sub-genotype was first isolated from a wild bird (common pheasant) in the Caspian Sea region. The five avian paramyxovirus 4 isolates obtained belonged to the common clade in Genotype I, whereas phylogenetic analysis of three isolates of Avian paramyxovirus 6 showed that two isolates, isolated in 2017, belonged to Genotype I and that an isolate identified in 2020 belonged to Genotype II. The continued regular monitoring of AIVs and APMVs, the obtaining of data on the biological properties of isolated strains, and the accumulation of information on virus host species will allow for the adequate planning of epidemiological measures, suggest the most likely routes of spread of the virus, and assist in the prediction of the introduction of the viruses in the western coastal region of the middle Caspian Sea.

Distribution of hydrogen sulfide, nitrogen and phosphorous species in inshore and offshore sediments of the south Caspian Sea.

This study aimed to geochemically investigate the sediments of the south Caspian Sea at different depths in summer and winter 2020. Sampling was conducted in 5 transects along the south coastline of the Caspian Sea and sediment grain size, hydrogen sulfide, Oxidation-reduction potential (Eh), total nitrogen, nitrite, nitrate, ammonium, total phosphorus, organic and inorganic phosphorous were measured. Eh values showed significant differences between seasons and between different transects (p < 0.05). Hydrogen sulfide ranged from 1.87 to 307.00 ppm. No significant difference was observed in hydrogen sulfide between seasons and among depths (p > 0.05). Total, inorganic and organic phosphorus contents were 782.96-1335.79 ppm, 639.66-1183.60 ppm, and 42.58-205.46 ppm, respectively. Total nitrogen revealed significant differences among transects (p < 0.05). Based on sediment quality guidelines, most sampling sites had alerting conditions for organic matter, and phosphorous contamination was detected at all stations. Anoxic condition was seen at most sites according to sedimentary Eh.

Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks.

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively.

Spatial and temporal distribution of physicochemical parameters of water in Gorgan Bay (the southeast of the Caspian Sea - Iran): Fundamentals for the monitoring of the Caspian Sea coastal areas.

Gorgan Bay as a main part of the Miankaleh (a natural biosphere reserve registered by UNESCO) is one of the richest ecological area in the West Asia and very important internationally recognized refuge for the wildlife. To date, multi physicochemical parameters have not been examined on a large scale. To fill this knowledge gap, the present study aimed to explore the seasonal and spatial variability of water quality parameters of the bay. The results showed that except for depth and transparency, there are significant variations in most parameters across the four seasons. The patterns of these changes in the bay vary, as evidenced by a comparison of the distribution maps of the various factors throughout the year. Notably, alkalinity declined from east to west, reaching its highest levels at important entry points such as the Qarasu River, Bandar-Gaz, and the pier. TDS, on the other hand, increased westward, reaching its highest concentration in the shallow western regions. Maximum depth (310 cm) and transparency (250 cm) were observed in the central bay. While the pH was higher in deeper areas, the distribution of PO4 was more uniform. With lower levels in the east (salinity = 0.40 ‰) and higher levels in the west (salinity = 28.9 ‰), the salinity showed a coherent gradient. Agricultural land use in the basin of the bay and fluxes of nutrients and sediments of the rivers entering the bay has significant contribution to the bay pollution situation. These results will serve as a guide for improving our understanding of the Gorgan Bay ecosystem. They also have implications for informed conservation and management plans adapted to the specifics of this special region within the Caspian Sea.

The decline of kilkas, sturgeons and seals in the Caspian Sea: The potential of qualitative loop analysis for the cumulative assessment of multiple drivers of stress.

Multiple stressors often act concomitantly on ecosystems but detection of species responses follows the "single species-single driver" strategy, and cumulative impacts are seldom considered. During 1990-2010, multiple perturbations in the Caspian Sea, led to the decline of kilka, sturgeon and Caspian seal populations. Specific causes for their collapse were identified but a cumulative assessment has never been carried out. Using loop analysis, a qualitative modelling technique suitable in poor-data contexts, we show how multiple drivers can be combined to assess their cumulative impact. We confirm that the decline of kilka, sturgeon and Caspian seal populations is compatible with a net effect of the concomitant perturbations. Kilkas collapse was certainly due to the outburst of M. leidyi and overfishing. In addition, the excess nutrient might have conspired to reduce these populations. The interplay between concurrent drivers produces trade-offs between opposite effects and ecosystem management must face this challenge.

Prediction of ctenophore Beroe ovata Bruguiere, 1789 habitat expansion and control of invading Mnemiopsis leidyi Agassiz, 1865 in the Ponto-Caspian basin associated with climate change.

The seas of Ponto-Caspian basin (Black, Azov and Caspian) are exposed to species invasions, including harmful ctenophore Mnemiopsis leidyi A. Agassiz, 1865 and its predator Beroe ovata Bruguière, 1789. Current environmental conditions of invasive ctenophores M. leidyi and B. ovata occurrence, development and variability in the Ponto-Caspian basin have been compiled, based on own field observations and published data. Analysis of climatological data on basic environmental parameters (water temperature, salinity, chlorophyll concentration) and modeling approach were used to predict favourable for both ctenophores conditions, and changes of those conditions, associated with the climate variations. The role of B. ovata as a bio-controller of M. leidyi population has been assessed. Several climate change scenarios have been considered in this study i.e., uniform increase/decrease of SST throughout the year by 2 °C and only spring temperatures increase/decrease by 2 °C. The most sensitive to increase in SST in terms of M. leidyi reproduction duration are the western coast of the Black Sea and the Southern and Middle Caspian. On the other hand, B. ovata reproduction duration is expected to increase in several areas, including the northern coast of the Black Sea and the Southern and Middle Caspian. The coastal areas of the Black Sea and the transitional regions between the Southern and Middle Caspian are exposed to an earlier start of M. leidyi reproduction during warmer springs. Regarding B. ovata, the whole Black Sea is vulnerable to spring SST changes, but in the Caspian Sea B. ovata extends its reproduction duration only in the Middle Caspian during warmer springs. Since B. ovata consumes mostly M. leidyi, it is an important biocontrolling agent of M. leidyi, harmless for the ecosystem.