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Plastic pollution is widely recognised as a pervasive anthropogenic pressure on coastal environments. Yet, beach-dune systems and dune vegetation remain considerably less studied than marine waters, beach sediments and aquatic biota. This paper presents a critical narrative review, supported by a spatial overview of the principal beach-dune systems along the Bulgarian Black Sea Coast based on recent dune inventory, mapping and litter-assessment data, with particular emphasis on microplastics, their occurrence, tra...

This study applies an adapted Living Planet Index (LPI) to assess long-term trends in fish populations in the Veleka River (southeastern Bulgaria) from 2010 to 2024. Based on standardized electrofishing data across seven stations, 11 native and naturalized species were analyzed using log-transformed abundance time series. The LPI declined from 1.0 in 2010 to 0.28 in 2024, indicating a 72% reduction in average fish abundance. Potamodromous species (e.g., Barbus cyclolepis, Chondrostoma vardarense) exhibited decline...

Coastal zones are among the most climate-vulnerable environments, exposed to extreme weather events, sea level rise, accelerating coastal erosion, biodiversity loss, and socio-economic vulnerability. As these pressures intensify, adaptation strategies have moved beyond engineered infrastructure toward nature-based solutions restoration interventions that work with ecosystems. One of most spread nature-based coastal restoration are seagrass and saltmarsh recovery, dune and wetland rebuilding, and integrated watersh...

Hermaphroditism in the flathead grey mullet (Mugil cephalus), manifested as intersex conditions, is linked to various environmental factors and anthropogenic pressures. Key contributors include exposure to endocrine-disrupting compounds (EDCs), heavy metals, and pollutants that disrupt hormonal regulation, leading to sexual development abnormalities. Research indicates that Mugil cephalus is particularly sensitive to EDCs in coastal and brackish ecosystems. Our findings reveal that 19% of male individuals from the...

This study examines the geomorphological and structural factors influencing the formation of coastal dunes along the Strandzha coastline of Bulgaria. Through the integration of GIS-based analyses, morphometric data, and geological profiles, the primary morphostructural units shaping coastal dynamics have been identified. These geological, morphostructural, and geomorphological conditions have provided the necessary prerequisites for dune formation. The research identifies a total of 17 dune systems along the Stran...

The coastal beach-dune systems along the Bulgarian coast are of significant ecological import, necessitating rigorous monitoring and management. Oversight and dune management inaccuracies have been recurrently identified, particularly within the Bulgarian Black Sea coast cadastral registers. This research highlights discrepancies in depositional areas, such as Asparuhovo-Varna, Byala, Burgas-South, and Poda beach-dune systems. The coastal dunes within these regions have been systematically documented through detai...

Presence of coastal structures usually causes significant impacts to adjacent shores, especially when they are composed of sand. Many times, these impacts are associated with inappropriate design due to inadequate consideration of hydromorphological processes and system interactions. As a result, excessive erosion and/or deposition of sediment is observed, which implies costly, and in some cases, continuous maintenance. The study presents an assessment and gives explanation of significant changes in the morphology...

The study presents the first comprehensive spatio-temporal analysis of eutrophication and the consequent loss of sensitive aquatic habitats in the transitional water bodies along the Kamchiya-Shkorpilovtsi sector of the Bulgarian Black Sea coast. The research focuses on the Maznia Azmak Lake, an old Kamchiya riverbed integral to the Kamchia Nature Reserve and two Natura 2000 protected areas. The primary objective was to assess the scale and rate of eutrophication and its impact on aquatic habitats, employing moder...

The present paper aims to mark the current status of knowledge regarding the area of the Town of Sozopol (ancient Apollonia Pontica) and its future research. The combination of geological and geomorphological data with the acquired archaeological and historical information can restore the ancient landscape of the study area. The research is focused on the landscape of Sozopol and its surroundings, due to it being among the most important areas in the history of the Western Black Sea. A mechanism for the formation ...

Water and sediments in coastal areas interact at different scales, thus shaping the marine environment and providing physical habitat for ecosystems. Hence, the hydromorphological conditions represent a key aspect of aquatic ecosystems considered in the Water Framework Directive as supporting quality elements (alongside the physicochemical), which are expected to provide the boundary conditions for the biological quality elements. Any alteration in those can reshape the corresponding biological conditions at vario...

Since putting in operation of Chernomorets fishing port (Sozopol municipality, southern Bulgarian Black Sea coast) in January 2016, a number of negative effects have been observed in the area. The disturbance in the existing hydrodynamic balance led to intense coastal erosion and unwanted sand accumulation in the wave shadow area. Additionally, the coastal water quality has deteriorated in the port area. In order to undertake measures to mitigate the observed adverse effects, it is necessary to assess in detail th...

The Bulgarian Black Sea Coast is a well-formed mosaic of pockets, small, gravellysandy beaches, and erosion-prone or erosion-resistant cliffs. A significant portion of the depositional cost along the Strandzha sector includes sand beaches with frontal and stabilized dunes, whose high-resolution mapping is a major task in this work. Currently, unmanned aerial systems (UAS) are the main method for topographic reconstruction. The world's experience in UAS surveys and the rapid capture of hard-to-reach large shore are...

The Marine Strategy Framework Directive (MSFD) is a framework for collective action in the marine environmental policy established by Directive 2008/56/EC of the European Parliament and the Council on 17 June 2008. It calls for EU Member States to create national marine strategies to achieve good environmental status (GES) by 2020 or to maintain it in areas where it already exists. Five factors are laid out in Commission Decision (EU) 2017/848 for GES assessment in regard to a number of broad habitat types, as two...

Knowledge of the coastal hydrodynamics, in particular the storm induced waves, is essential for management of the extremely vulnerable coastal environment. There, wave processes dominate surge, coastal currents, sediment transport and species distribution. Therefore, it is important to have a detailed insight into the exposure of different coastal areas to wave action. The study proposes a wave exposure classification of the Bulgarian Black Sea coast according to wave climate conditions as required by the Water Fr...

The food spectrum of three fish species from the Mugilidae family in different age groups was studied. The samples were collected in 2019 - 2021 from the river estuaries and the coastal brackish lakes at the Bulgarian Black Sea coast. The research aims to establish the food spectrum of mullets and thus make a connection between food components. The results show that the predominant groups in the stomachs of the three mullet species are detritus, zoobenthos (Rissoa sp. And Trochammina inflate - 64.28%) and macrophy...

The Varna and Beloslav lakes are the most strongly anthropogenized water bodies along the Bulgarian coast. At present, the lakes are again subject to deepening of the navigable channel, which significantly changes the quality of the habitats. An ecosystem approach was used to assess the status of the populations of fish species from the Varna-Beloslav Lake Complex. The paper's main purpose is to provide up-to-date information on the ichthyofauna of the largest northern Bulgarian Black sea brackish water bodies - V...

The Durankulak Lake is the northernmost Bulgarian Black Sea lagoon. The hydrological regime of the lake is, for the most part, the inflow of water in karst underground cracks. Over the years, the rare cases of digging a sea-lake canal have been a significant cause of the oligohaline estuarine wetlands nature of the water body. The publication aims to present current research on the structure of the lake bottom, the heart of the substrate and changes over the years, using data from a multi-beam echo sounder and sid...

For the period 2011-2021, 231 fish species from 18 families were established in protected area BG0000271 -Mandra-Poda-, 345 fish species from 7 families in protected area BG0001502 -Otmanli- and 169 species from 11 families in a protected area BG0000242 -Chengene skele Bay-. One hundred eighty-seven of the species were freshwater, 256 were typical marine fish species, and the other one hundred and fifteen were anadromous and brackish species. Protected species are Rhodeus amarus, Cobitis taenia, Chalcalburnus chal...

In the restoration of the historical and geographical conditions of today's Bulgarian lands, historical sources and documents of different origin, character and purpose come into use. The lack of sufficiently complete and accurate information about the development and dynamics of coastal archaeological landscapes in the narrative source material enhances the importance of medieval and renaissance maps of the Black Sea basin, which are an invaluable source of information. The combination of this information, togeth...

The present study is aimed to assess the status of Black Sea fish species harvested by the Bulgarian fishing fleet, according to the three criteria of Descriptor D3 under the Marine Strategy Framework Directive (MSFD). Achieving healthy fish populations depends on the adverse impact on species as a result of fishing activity. Descriptor D3 of MSFD addresses the commercial fish stocks status by applying indicators assessing the exploited fish sustainability, reproductive capacity and recruitment, and the age and si...

The study aims to assess the diversity, density, and heterogeneity of seafloor litter, distributed in the Bulgarian Black Sea’s shelf area. The indicators for assessment follow the national monitoring program under Descriptor D10 of the Marine Strategy Framework Directive. The survey campaign took place between 19.10 – 14.11.2017. Marine debris was gathered by 53 trawl hauls distributed in four regions at depths between 30 and 100m. During the survey, all litter items were collected and classified into seven categ...

Transitional (brackish) water bodies host extremely vulnerable ecosystems. They are highly sensitive to pollution, changes in the water currents, nutrient levels, etc. Over the course of the 20th century in Bulgaria, many of them were purposely drained or strongly altered. Today, these fragile ecosystems account for just 0.1% of Bulgaria’s area, and hence they are listed among the country’s top priority nature conservation sites. The long-term preservation and survival of numerous rare or threatened hydrobionts de...

High-resolution imagery guarantees excellent quality of coastal topographic surveys. Alongside the rapid progress of remote sensing, digital photogrammetry and image processing in recent years using unmanned aerial vehicles (UAVs) provide outstanding opportunities for mapping the coastal zone, including the coverage of difficult-to-access areas, as is the Northern Bulgarian coast. Both spatial planning and integrated coastal zone management require highly accurate and up-to-date geodata, being among the main reaso...

The article presents some case studies of negative impact of human activities on underwater cultural heritage from Black Sea. A serious problem is the pollution and the litter disposal in the historical harbours. The resulting conditions often endanger some impressive and well-preserved underwater cultural heritage sites. An advanced methodology for litter registering and assessment was developed and applied using remote sensing with side scan sonar, subbottom profiler and orthophotography using a drone. The surve...

Over 30% of the Bulgarian Black Sea shoreline is characterized as a depositional type of coast. A significant portion of it represents well-formed sandy beaches and dune fields, falling under the protection of the European ecological network NATURA 2000. The coastal sector of the Lower Kamchia Depression hosts the longest beach-dune system on the Bulgarian Black Sea coast called Kamchia-Shkorpilovtsi beach. The main task of the project "Mapping and monitoring of depositional areas along the Northern Bulgarian Blac...

The aerial imagery has a long tradition of use as a surveying method in underwater archaeology. With the recent development of new technologies, its application has become more versatile and more common. This article will present the use of aerial photogrammetry in the archaeological survey of the submerged heritage of Nessebar, ancient Mesambria, on the Bulgarian Black Sea coast. A major application is the generation of a digital bathymetric model (DBM) of the seafloor, which is reliable and accurate approximatel...

The study of the specific nature of the coastal zone requires a combination of a wide range of data from multi-beam and single-beam echosounding, LiDAR scanning, unmanned aerial vehicles, and generation of accurate high-resolution digital terrain models. In recent years, the development of seabed mapping technology has allowed for more precise mapping of the coastal zone. The complex analysis of data on relief, morphostructural units, contemporary tectonic deformations, geological and lithostratigraphical structur...

Low-altitude remote sensing technology applied with unmanned aerial vehicles (UAVs) has been recently adopted in Bulgaria. This study presents the optimal low-budget framework for a rapid high-resolution geomorphological mapping of a small part of the southern Bulgarian Black Sea coastal zone. A Quadcopter DJI Phantom 4 Pro was used to acquire the aerial images. These were post-processed using the structure-from-motion (SfM) approach. Ground control points (GCPs) surveyed with a GPS HiTarget V90 Plus were applied ...