Greece exhibits the lowest seafood per capita consumption amongst European Mediterranean countries, and the investigation of consumer attitudes to new seafood products would bridge the gap among producers and consumers by promoting the vertical integration of the supply chain. However, limited information exists about consumer preferences for bivalves in the Mediterranean and for wild bivalves in particular. The present study aims to investigate, for the first time, consumers’ attitudes towards the purchase and consumption of bivalves, and more specifically, towards the edible pearl oyster Pinctada imbricata radiata, in the Greek shellfish market. Adult participants from the entire country completed a questionnaire covering the basic marketing aspects of bivalve and pearl oyster consumption, such as choice, purchase, reasons for consuming bivalves, confidence in product’s hygiene certification, media influence, etc. Data analysis included uni- and multi-variate statistics to examine the possible relations between the consumers’ demographics and socio-economic characteristics, and bivalve marketing aspects. Results showed that the majority of Greek consumers chooses traditional shellfish shops for purchasing pearl oysters, prefers a certification of quality, and trusts the confirmation provided by the veterinary authorities. Consumers’ attitudes vary considerably according to their demographics and socio-economic characteristics. Multivariate models revealed that the married, highly educated consumers that live in urban places were more reluctant to try new shellfish products and to accept an innovative way of market supply. The results reflect the positive attitude of Greek consumers towards the consumption of pearl oyster, a fact that would be helpful for decision makers in the planning of production, which in turn would promote bivalve consumption in the Greek shellfish market.

The present study investigates through an integrated survey, for the first time in Greek shellfish market, the marketing distribution towards a new edible shellfish product that of the non-indigenous pearl oyster Pinctada imbricata radiata. The survey conducted through personal interviews on sector entrepreneurs/staff of the supply (i.e., shellfish producers, wholesalers, fishmongers, owners of restaurants). Internet-based quantitative research was also conducted to explore the market supply of the pearl oyster covering all nine regional units of Greece. The market for pearl oyster seems to be there as a substitute of the major commercial species in seasons of shortages. There is a specimen mislabeling throughout Greece, thus, extraction of significant information about the market supply of pearl oyster is deficient. Further knowledge on the bivalve shellfish value chain is needed, to define how the wild and the farmed species (mussels) interact in the market and in the distribution channels, toward a product-easy to use in the supply chain and friendly to the consumer. Findings also raises additional concerns as a priority for conservation, and the current practices do not satisfy the Common Fisheries Policy in terms of traceability.

In the present study, the biology of the pumpkinseed Lepomis gibbosus in the artificial lake of Aoos, located in northwestern Greece, was investigated. The samplings of the pumpkinseed were conducted from the shore using a portable electrofishing device over a 4-month period (July 2021–October 2021). A total of 581 specimens were caught, with an average length of 62 mm. The sex ratio of female to male was estimated to be 1.0:1.7, and the percentage of mature specimens was estimated for all of the months to be above 52%, matching the highest percentage in July (57.4%). The b value of the length–weight relationship ranged from 3.16 in September to 3.31 in July. The value of the L∞ and K was estimated to be equal to 119 mm and 0.36 years⁻¹, respectively, and the value of φ′ was equal to 3.707. The total mortality was estimated to be equal to 1.63 ± 0.48 y⁻¹ (R² = 0.96), and the natural and fishing mortalities were 0.83 and 0.80, respectively. The maximum age was 6 years, and the theoretical maximum age was 8 years. In the current study, the value of the L∞ was estimated to be near the European average but significantly lower than the North American one, whereas the value of the K was slightly higher than the European average. The small size of the specimens obtained in Aoos Springs was most likely owed to the combined impact of the investigated lake’s high altitude and low food availability, resulting in a limited factor for species expansion.

The impoundment of Aoos springs was created in 1990 to facilitate hydroelectric production, and fish fauna has been enriched through the years due to deliberate or accidental fish stockings, with certain invasive alien fish species arising (i.e., Lepomis gibbosus, Carassius gibelio), some of which are ranked among the most dangerous species for global biodiversity. A three-year monitoring survey was conducting to map the nesting areas of Pumpkinseed, L. gibbosus, to assess the effectiveness of electrofishing as an active method to reduce the spread of the corresponding species and to identify the impact of the L. gibbosus on native species. The largest percentage of nests was found in areas with silty-sand bottoms (53.4%) and low vegetation. The potential nesting area was estimated at 1.97 km² and the area of confirmed nesting was 0.33 km². The species appeared to nest in a small area, compared to the potential nesting area. The results also indicate that a significant percentage of the target species (71.6% of the total number of species) was removed, with an average time per sampling of 1.2 ± 1 h, whereas the impact on the other native species was minimal. These results are important for designing and implementing programs for the eradication or reduction of L. gibbosus in the impoundment of Aoos springs.

The ecosystem structure of a Mediterranean high-altitude artificial lake (Aoos Springs, Northwest Greece) was assessed and quantified using the Ecopath with Ecosim model. The artificial lake was created in 1990 for hydroelectric production and the fish fauna has been enriched across years due to deliberate or accidental fish stockings, as well as the introduction of the invasive pumpkinseed (Lepomis gibbosus), which may cause adverse effects on aquatic ecosystems and their biota. The model considered 20 species/taxa groups with biological data gathered during 2021–2022 from field surveys, interviews with recreational anglers and literature. The results revealed that the artificial lake of Aoos is a resilient ecosystem to unexpected events with low intensity of fisheries exploitation. The biomass of the introduced invasive species Lepomis gibbosus is low, due to the low biomass level of its diet, Chironomidae and zoobenthic organisms as well as other fish species.