Search Results (7)

Among the commercial mollusks from the Black Sea, the ark clam Anadara kagoshimensis, the oyster Crassostrea gigas, the mussel Mytilus galloprovincialis, the scallop Flexopecten glaber ponticus, and the gastropod Rapana venosa hold the top positions in terms of cultivation and harvesting volumes. Mollusk shells are attracting attention due to their potential use in various biotechnological applications, including nutraceutical production. In the present study, using inductively coupled plasma mass spectrometry, concentrations of essential trace elements (Cr, Mn, Fe, Co, Cu, Zn, Se, Mo, and I) were measured in shells of the five mollusks sampled from the same biotope. The essential element concentrations in the mollusk shells differed significantly. The highest concentrations of Cr, Mn, and I were found in Anadara shells; Fe and Co in Crassostrea shells; Zn in Mytilus shells; and Cu and Se in Rapana shells. Principal component analyses demonstrated the overall accumulation of all elements as the main cause of the total data variance and the species-specific accumulation of certain elements as the second most important source of the data dispersion. Matrices of element concentration correlations showed considerable dissimilarity, which suggested species specificity in the concerted or competing element accumulation. Powdered shells of Anadara, Crassostrea, and Rapana are most suitable to fulfill the daily human requirements for many essential elements, and the consumption of these powders in amounts of less than a few tens of grams appears to be sufficient for this purpose. Full article

In this study, we employed geometric morphometrics (GMs) to analyze the shell shape differences among two mass-selected strains of bay scallops (red shell strain (RS) and black shell strain (BS)) and a control group (CG). The results revealed distinct shell shape differences corresponding to shell coloration, with the black shell strain displaying a more elliptical shell compared to the red shell strain. Additionally, the umbonal angle of the red shell strain was smaller than that of the black shell strain, indicating that the black shell strain had a more favorable jet direction that could enhance swimming capabilities. To evaluate the model’s performance in practical applications, leave-one-out cross-validation was carried out on the two shell strains and one control group. The results demonstrated discrimination accuracy rates of 67.44%, 47.62%, and 68.18% for the BS strain, RS strain, and CG, respectively. Similarly, for the right valves, the discrimination accuracy rates were 62.79%, 50.00%, and 75.00% for the BS strain, RS strain, and CG, respectively. Full article

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. Full article

A new malachite beetle, Baltamauroania mirabilicornis gen. et sp. nov., belonging to the tribe Amauroniodini (Coleoptera: Dasytidae) embedded in Eocene Baltic amber is described and illustrated. The new genus differs from the congeners of the tribe Amauroniodini in possessing a black, elongated, and subparallel body and a pronotum with scalloped lateral sides; long and 11-segmented antennae, with three apical antennomeres enlarged and forming a ‘club’ shape, with cylindrical antennomere 1; tarsi shortened and compressed, 5-segmented, with tarsomeres 1 and 2 equal in length, and tarsomere 5 the longest in all legs; pubescence of the dorsal surface consisting of short strong brown semi-erect and fine adpressed setae; punctation of dorsal surface irregular, elytra lacking grooves; pronotum almost equilateral, slightly elongated, with acute anterior and obtuse posterior angles, with wide margination of basal side and with scalloped and finely margined lateral sides; lateral edges of pronotum weakly rounded, with obtuse protuberance before middle. This is the second extinct genus and third record of the subfamily Danaceinae found in Eocene amber. The fossil records of the family Dasytidae are discussed. Three recent records of different Amauroniodini taxa from Eocene East European amber (Baltic and Rovno) show there to have been a high Danaceinae biodiversity in both the southern coast of the Subparatethys (documented by Rovno amber) and in its northern coast (documented by Baltic amber). The phenomenon of Danaceinae diversity in the Eocene Epoch is discussed. Full article

The use of biological objects in monitoring the state of the environment and the changes caused by the impact of environmental pollution on marine and fresh waters is a promising tool due to a lower cost in comparison to traditional monitoring and the ability to receive immediate information about the ecosystem status. In this review, we summarize the biological information about shellfish biomonitors and the results of studies focused on the development and use of the bioindicator species in early warning systems in Russia. Since the mid-1980s, Russian specialists have developed online biomonitoring systems; as in the rest of world, there are two main approaches that are currently applied to study the physiological status of potential biosensor shellfish species and to monitor freshwater and marine systems: valvometry (registration of gaping activity in bivalve mollusks) and photoplethysmography (registration of cardiac activity in mollusks and crustaceans). Valve movement responses to stressors such as abnormal conditions and pollutants include the closure of shell valves for a long period, decrease in the average distance between valves, rapid shell opening, and higher closing frequency. Cardiac activity reactions of shellfish to stress factors include rapid increases in heart rate and stress index, higher variability in heart rate than under normal conditions, and longer periods required for heart rate recovery after stress. The most common bioindicators used to monitor environmental disturbances in marine ecosystems are blue mussels, Iceland scallops, and red king crabs in cold-water habitats and Black Sea mussels in warmer waters as well as freshwater mussels and crayfish in fresh waters. Full article

The discovery of the Aleurocanthus cf. Aleurocanthus spiniferus (Tea spiny whitefly spiniferus morphotype; previously found in Tokyo) for the first time in Shizuoka Prefecture raised the possibility that this species had invaded Honshu Island, Japan. Unlike the allied species, Aleurocanthus spiniferus and A. camelliae, which have been intercepted from China to Japan, the origin of the current species remains unclear. Despite the status of this species as a minor pest on the ornamental plant, Eurya japonica, the cryptic diversity among the black spiny whitefly is fascinating to be elucidated, specifically how the primary endosymbiont of whiteflies, Portiera aleyrodidarum, coevolved and contributed to the classification of whiteflies. The current study examines the taxonomic status of five species of whiteflies, i.e., A. spiniferus (Quaintance), Aleurocanthus aff. A. camelliae, Aleurocanthus cf. A. spiniferus, A. camelliae Kanmiya and Kasai, Aleurotrachelus camelliae Kuwana, and A. ishigakiensis Takahashi. Using consortium molecular typing targeting mitochondrial DNA (COI and 16S of mitoribosome), the nuclear gene (ITS1), and the ribosomal gene of Portiera, the phylogenetic clustering analysis has been conducted and revealed that the genus Aleurotrachelus sensu lato was clustered together with Aleurocanthini Takahashi, 1954 stat. rev. and reinstated Crenidorsum ishigakiensis comb. nov. due to crescent-shaped scallops being clearly defined. The current study also unveiled several putative species in the A. spiniferus species complex, molecularly. In addition, the recombination event was not detected in Portiera but has been detected in the mtCOI genes of the A. spiniferus cryptic species and the A. woglumi sequences deposited in the NCBI database. The mitochondrial recombination gives an insight into the speciation process among this species complex. Full article

The present study examines the juvenile growth of nine cohorts of Mimachlamys varia in a coastal area of the Ionian Sea, from January 2014 to May 2015. The results showed that M. varia could reach commercial size in less than one year of cultivation, but significant differences in absolute growth rate (AGR) and specific growth rate (SGR) were found among cohorts (p < 0.05). Relationships between scallop growth (size and weight) and environmental variables (water temperature, dissolved oxygen and chlorophyll concentration) were also identified. The length–weight relationship showed negative allometric growth and indicated high correlation with R², ranging from 0.95 to 0.82. Von Bertalanffy growth parameters showed the highest values of L_∞ in the cohorts collected in January, April and February (52.2, 51.2 and 50.3), respectively. The growth performance index (φ’) ranged between 2.52 (cohort collected in June) and 3.03 (cohort collected in August). The obtained data add basic knowledge to the growth performance of this species, making this a good opportunity to facilitate aquaculture diversification in this part of Mediterranean Sea. Full article