Search Results (11)

In an effort to monitor ascidian recruitment in mussel aquaculture facilities, a series of settlement plates (20 × 20 cm) were placed in a mussel farm located in the Amvrakikos Gulf (Ionian Sea). The plates were vertically deployed on floating facilities in the water column at regular intervals (depths of 0.2 m, 1.5 m, and 3 m) to monitor the settlement and proliferation of ascidians. Furthermore, measurements of seawater physicochemical parameters such as temperature, salinity, dissolved oxygen, and chlorophyll-a concentration were conducted together with the record of ascidian species in each sampling from January 2021 to November 2021. The correlation of these parameters with ascidian species provides information on their effect on the periodicity of ascidians’ recruitment. The results demonstrated a significant correlation between ascidian presence and water temperature. The potential influence of other important environmental parameters such as chlorophyll-a was not revealed, likely due to the limited number of values and samples included in the analyses. While increased chlorophyll levels, reflecting increased primary productivity or nutrient availability, are associated with increased growth and reproduction of all ascidian species, the effect of temperature was more potent and species-specific. Ciona robusta, Styela plicata, Microcosmus squamiger, and Phallusia mammillata were mainly detected at temperatures below 25 °C, whereas Clavelina oblonga was prevalent at temperatures above 25 °C. The absence of most ascidians at temperatures above 25 °C was possibly attributed to decreased settlement success and to the increased competition from C. oblonga at higher temperatures. The deployment of settlement plates in correlation with seawater physiochemical parameters can provide valuable data on ascidian settlement dynamics and support the development of targeted management practices for biofouling control. Full article

Wetlands are highly productive ecosystems with multidimensional value and significant social and economic impacts. Estimating the economic value of their non-marketed goods and services—benefits not traded in conventional markets—can provide essential insights to guide protection, restoration, and sustainable management strategies for these sensitive ecosystems. The present study employs environmental economics tools, specifically the Contingent Valuation Method (CVM), to assess the value of the Amvrakikos Gulf in northwestern Greece. This semi-enclosed wetland system is particularly fragile due to its low water renewal rate, while being a primary source of income and an integral component of local cultural identity. Despite its high ecological importance, the Amvrakikos Gulf has experienced substantial environmental degradation stemming from its geomorphological characteristics and external anthropogenic pressures. This investigation was designed to explore residents’ perceptions of the wetland’s value and its correlation with the need for restoration. In total, 383 coastal area residents participated in this study. Data analysis was conducted using appropriate econometric methods based on both parametric and non-parametric models. Approximately 46.2% of respondents expressed willingness to pay, and the environmental restoration of the Amvrakikos Gulf was valued at EUR 715,968.36. Additionally, this study examined potential associations between willingness to pay and various socio-cultural and demographic factors recorded during the interviews. In conclusion, the need for the restoration and preservation of the Amvrakikos Gulf’s natural wealth was made evident, affirming the contribution of the CVM in valuing wetlands and enriching the existing literature, while explicitly recognizing the subjectivity inherent in WTP assessments. Full article

Pinna nobilis, endemic to the Mediterranean Sea, has been experiencing a gradual population decline over recent decades due to anthropogenic pressures on its ecosystems. However, since 2016, its populations have suffered significant reductions because of pathological issues affecting the species across all its habitats. Aquaculture techniques to support the limited natural recruitment P. nobilis efforts is examined. Artificial substrates for larval attachments in aquaculture infrastructures promote the survival of the juveniles that is further enhanced through protected pre-growing “nursery” farming conditions. Specific spat collectors were placed in 2 cage-fish farms in SW Amvrakikos Gulf. The harvested spats from were transferred to pre-grow in trays hanged on a long line farm mussel that is acting as a protected “nursery”, avoiding predation and any human accidentally disturbance. The survival and growth of 12 juveniles P. nobilis spat (shell length 38.1 ± 9.2 mm) in captivity (31 October 2023–15 March2023) was investigated. Out of the 12 individuals collected, 3 were examined for the presence of pathogens; only 7 survived, exhibiting enhanced growth (shell length 54.3 ± 11.6 mm) after 134 days in the nursery. The results highlight the significant role of aquaculture techniques in efforts to conserve a threatened species as well as the need for the creation of a protocol to ensure the conservation of P. nobilis. Full article

Amvrakikos Gulf and its surrounding coastal lagoons are of primary importance for the local biodiversity and fishing activities. Fish species inhabited the coastal lagoons based on the seasonal ongoing migration movements of fry and adult fish individuals from the sea towards the lagoons. Information on the early stages of fish and decapod species in the Amvrakikos Gulf is limited only to the planktonic ontogenetic stages and reproduction biology, respectively. The aim of this study was to describe the spatial distribution of fry from commercially important fish and decapod species in the coastal zone of Amvrakikos Gulf. The seasonal appearance of the early stage of the most commercially important fish species caught in the coastal zone of the gulf ranged from one to four seasons, depending on the species. Individuals of all ontogenetic stages (fry, juveniles, and adults) were reported for several species (A. boyeri, A. fasciatus, S. abaster, S. tyfle, and B. ocellaris), indicating that these species may be regarded as residents in the coastal zone, providing habitats for their entire life cycle. The average relative abundance of the species/genera exhibited no differences compared to other Greek brackish waters. The species composition in the Amvrakikos Gulf at 10 cm and above was in agreement with the transitional nature of the area, with permanent and occasional species present. The present study emphasizes the importance of the coastal zone as a nursery habitat for commercially important species. Full article

AliAmvra is a project developed to explore and promote high-quality catches of the Amvrakikos Gulf (GP) to Artas’ wider regions. In addition, this project aimed to implement an integrated plan of action to form a business identity with high added value and achieve integrated business services adapted to the special characteristics of the area. The action plan for this project was to actively search for new markets, create a collective identity for the products, promote their quality and added value, engage in gastronomes and tasting exhibitions, dissemination and publicity actions, as well as enhance the quality of the products and markets based on the customer needs. The primary focus of this study is to observe and analyze the data retrieved from various tasting exhibitions of the AliAmvra project, with a target goal of improving customer experience and product quality. An extensive analysis was conducted for this study by collecting data through surveys that took place in the gastronomes of the AliAmvra project. Our objective was to conduct two types of reviews, one focused in data analysis and the other on evaluating model-driven algorithms. Each review utilized a survey with an individual structure, with each one serving a different purpose. In addition, our model review focused its attention on developing a robust recommendation system with said data. The algorithms we evaluated were MLP (multi-layered perceptron), RBF (radial basis function), GenClass, NNC (neural network construction), and FC (feature construction), which were used for the implementation of the recommendation system. As our final verdict, we determined that FC (feature construction) performed best, presenting the lowest classification rate of 24.87%, whilst the algorithm that performed the worst on average was RBF (radial basis function). Our final objective was to showcase and expand the work put into the AliAmvra project through this analysis. Full article

The present study aims through a modeling approach to quantify fishing losses from the impact of great cormorants (Phalacrocorax carbo sinensis) during their wintering period in Greek lagoons. A number of assumptions were incorporated into the model regarding fish population growth, species distribution, age (or size) of fish caught, and the different fishing strategies that could be applied in the studied lagoons. The results indicated that the mean value of daily economic losses ranged from 0.614 to 1.075 €·bird⁻¹·day⁻¹, whereas the ratios of biomass losses to landings biomass and of economic losses to economic profit ranged from 0.18:1 to 3.80:1 and from 0.14:1 to 4.18:1, respectively, depending on the lagoon. The results supported a strong competitive relationship between great cormorants and fisheries in lagoons of the Amvrakikos Gulf. Full article

The modern drainage systems of the fold and thrust belt of the external Hellenide orogen of NW Greece are principally orogen-parallel. Late Quaternary changes in river courses have resulted from neotectonic deformation associated with the Katouna–Stamna fault and with footwall uplift in developing transverse grabens. This study assesses the impact of neotectonic deformation on river patterns and basin deposition. River sands show differences in modal abundance and varietal geochemistry of heavy minerals and fine sand lithic clasts, determined by scanning electron microscope, that allow identification of past river supply to raised fluvial terrace and beach deposits. In the past 200 ka, footwall uplift south of developing grabens at Lake Trichonis and the Amvrakikos Gulf promoted orogen-transverse flow, diverting the Arachthos-Louros rivers to the west, causing reversal of drainage to the north in the lower reach of the Acheloos River. A raised terrace gravel south of Preveza records the southwestward flow of a large paleo-Arachthos river, confirmed by sand petrology in beaches farther south on the Echinadon Sea coast. The use of varietal heavy minerals and lithic clasts is a rapid and powerful tool for tracking tectonically-induced changes in river patterns. Full article

The current study provides valuable insight into the ecological risks and decline of the bivalve fishery and biodiversity in the Amvrakikos Gulf over the last 50 years through a triangulation of information from in situ surveys and expert judgment, supplemented with historical archives. In situ sampling showed that bivalve species composition was a typical composition of benthic fauna consisting of the olive green cockle, Cerastoderma glaucum, the grooved carpet shell, Ruditapes decussatus, and the Mediterranean mussel, Mytilus galloprovincialis. Interviews confirmed the dramatic decrease in the abundance of striped venus clam, Chamelea gallina, and noble pen shell Pinna nobilis, both of which might be attributed to human-induced impacts, habitat degradation and climate change. Official data depicted a gradual reduction of bivalve catches since 1980 and massive degradation of the resources after 2000. As a result, the bivalve fishery was abandoned, having a negative impact on the local socio-economic community. The present study fills in a gap in knowledge for preserving species biodiversity that is critical to the health of the coastal environments. Full article

Amvrakikos Gulf is a Mediterranean landlocked, fjord-like embayment and marine protected area suffering from natural, human-induced hypoxia/anoxia and massive fish mortality events. Seasonal marine geophysical and oceanographic surveys were conducted focusing on the water-circulation patterns at the sill and the spatial-seasonal distribution of dissolved oxygen (DO) in the gulf. Detailed surveys at the sill, the only communication route between the gulf and the open sea, revealed a two-layer water circulation pattern (top brackish outflow–bottom seawater inflow) and the role of the tide in the daily water exchange. Statistical analysis of the known natural drivers of DO distribution (density difference between the Ionian Sea and Amvrakikos, river inflow, wind) revealed that horizontal density gradients strongly affect anoxia reduction and seafloor oxygenation, while river inflow and wind mainly oxygenate volume/areas located above or within the pycnocline range, with DO concentrations > 2 mg/L. Complex geomorphology with well-formed internal basins contributes to the development and preservation of low DO conditions below the pycnocline. Finally, 43% of the seafloor and 36% of the gulf’s total water volume are permanently hypoxic, and reach a maximum of 70% and 62%, respectively, in September and July. This work is tailored to future ecosystem management plans, decisions, and future research on coastal ecosystems. Full article

Amfilochia Bay (Eastern Amvrakikos Gulf, Western Greece), a complex marine area affected by tectonism, was investigated for seabed seepage manifestations and for possible inter-relationships between shallow gas accumulations and hypoxia. For this purpose, an integrated research methodology that combined geophysical, geochemical, and hydrographic surveys was applied. Marine geophysical and bathymetric surveys led to the discovery of a gas-induced pockmark group in the study area. Oceanographic surveying confirmed that the bay is hypoxic/anoxic below a depth of 15 m (dissolved oxygen from ~4 to 60 μM). Very weak CH₄ seepage was detected in correspondence to the pockmark group that seemed to slightly enhance the hypoxic environment locally and close to the seabed, with no effect in shallower waters and the oxycline. Methane isotopic analysis showed variable carbon isotopic composition (from −41‰ to −86‰) which could be either related to differential CH₄ oxidation or mixing between microbial and thermogenic gas. However, the pathway of degassing is clearly related to the fault-controlled pockmark group. A protrusion mound, which has erroneously been reported as a submarine “volcano” since 1876, could be the result of mud volcanism based on the geophysical data of this study. Full article

Plastic waste pollution in marine environments is considered a major environmental problem in coastal areas. Relative environmental problems are also recorded in protected wetlands. The National Park of Amvrakikos Wetlands, one of the largest wetlands of Greece, is studied in order to evaluate the influence of plastic waste in the protected area and its surroundings, according to the stakeholders’ views. The survey applied using the method of census addressing the key stakeholders in the area of interest and the use of a questionnaire; the data analyzed with the Statistical Package SSPS. The main findings reveal that waste management is not considered satisfactory in the broader area. Marine litter, pollution, overfishing, ecosystem degradation, agriculture and livestock activities, as well as the insufficiency of the municipal solid waste management and recycling system are listed as the most important environmental problems of the coastal area. The stakeholders’ participation is regarded as crucial for effective decision making. Therefore, special strategies should be designed involving Information and Communication Technology (ICT) to widely address the local communities and increase their awareness on the problem in order to reduce plastic waste pollution. It should be noted that environmental conditions are closely affiliated with the citizens’ quality of life. Full article