Flexopecten Glaber Research Articles

Antioxidant Complex of the Black Sea Bivalve <i>Flexopecten glaber ponticus</i> (Bucquoy, Dautzenberg et Dollfus, 1889) in Natural Habitat

The antioxidant (AO) defense complex in tissues of the scallop Flexopecten glaber ponticus (Bucquoy, Dautzenberg et Dollfus, 1889) from a natural habitat in the Black Sea was studied for the first time. The results indicated a pronounced tissue specificity of the scallop AO complex along with close levels of TBA-reactive substances in all the studied organs. In the gills of the scallop, the activity of glutathione reductase (GR), superoxide dismutase (SOD), and catalase was higher compared to the hepatopancreas. The activity of glutathione peroxidase (GP), GR, and catalase in the gills was higher than in the muscle. The reduced glutathione (GSH) reserve in the gills was lower than in the hepatopancreas. This indicated that both the glutathione system and the key antioxidant enzymes, SOD and catalase, significantly contributed to the antioxidant defense of the scallop gills. In the hepatopancreas, the level of glutathione was the highest and the activity of GP was high and similar to that in the gills. This reflects their significant role in the AO defense of this organ. However, the activity of GR, SOD, and catalase in the hepatopancreas was significantly lower than in the gills. The scallop muscle was characterized by the lowest GP activity and a low GSH level, close to that in the gills. The SOD activity in the muscle was comparable to its value in the gills, and the activity of catalase and GR was comparable to the values in the scallop hepatopancreas.

From Isolated Valves to a Potential Marine Living Resource: History, Documented Distribution and Sustainable Population Enhancement Possibilities of the Smooth Scallop (Flexopecten glaber) on the Romanian Coast

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.

Rare Earth Elements in Shells of Black Sea Molluscs: Anomalies and Biogeochemical Implications

Rare earth elements (REE) are a class of increasingly used high-tech product components and new emerging environmental pollutants, which are accumulated, in particular, in marine biota. In this study, REE contents were estimated in shells of several molluscs common in the Black Sea. The summed REE contents in mollusc shells decreased in the following order of species: Magallana gigas = Anadara kagoshimensis > Flexopecten glaber ponticus ≥ Rapana venosa > Mytilus galloprovincialis, ranging from 0.46 to 1.9 mg·kg−1. Canonical analysis of principal coordinates allowed for the correct identification of species based on the REE composition in no fewer than 67% of the samples. The mollusc shells were anomalously enriched in Sc, Y, La, Eu and Tb, most likely due to anthropogenic contamination. The Y/Ho ratios in all samples were represented by two fit values: 23.2 (chondritic) and 67.6 (superchondritic, mainly associated with A. kagoshimensis). A new universal relationship linking the contents of three light and heavy REE in Black Sea mollusc shells was proposed: Ce0.3 Er0.7/Yb = 2.00 ± 0.46 (mean ± standard deviation).

Projecting expected growth period of bivalves in a coastal temperate sea

AbstractThe impact of climate warming on coastal benthic fauna is already observed, but forecasting their long‐term fate remains challenging. This study uses δ18Oshell data of specimens of five bivalve species collected at six locations and results from kilometer‐scale atmosphere–ocean climate model for the time intervals of 1987–2017 and 2070–2100, to estimate changes in bivalve growth phenology. All species will benefit from climate warming during winter, experiencing a longer growing season than currently. The growth of Aequipecten opercularis, Flexopecten glaber, and Pecten jacobaeus will decrease in summer, resulting in up to 3 months of reduced growth per year. Glycymeris pilosa and Venus verrucosa in the southern Adriatic Sea will be more affected than those in the north, with up to 4 months longer annual growth. These findings can inform adaptation plans for bivalve management in the Adriatic Sea but also in areas where the studied species are present.

Comparative Aspects of the Study of Morphophysiological and Biochemical Parameters of Somatic Growth in Populations of Two Species of Black Sea Bivalvia Mollusks: Cerastoderma glaucum and Flexopecten glaber ponticus

Comparative Aspects of the Study of Morphophysiological and Biochemical Parameters of Somatic Growth in Populations of Two Species of Black Sea Bivalvia Mollusks: Cerastoderma glaucum and Flexopecten glaber ponticus

Cyclicity in ontogeny and age determination of Flexopecten glaber (Bivalvia, Pectinidae) in the Black Sea

Flexopecten glaber is an actively fished species in the Mediterranean Sea and a promising candidate for mariculture in the Black Sea. Flexopecten glaber is included in the Red Data Books of the Republic of Crimea and Sevastopol city as a species declining in number (Category 2). In this study, over 1500 specimens sampled near the Crimean Peninsula between 2017 and 2023 were analysed to investigate the ontogeny of F. glaber and develop a method for determining individual age, based on the relationship between stages of gonadal development and changes in shell surface morphology. The cyclicity of development was assessed by comparing the cycles of gonad formation with the features of the surface morphology of the shell. A correlation was found between the morphology of the surface of shell valves and the stages of the annual cycle of gonad development. On this basis, a scheme for determining the developmental stages and individual age of F. glaber specimens from the morphology of shell valves has been developed. The most prominent mark on the shell surface is formed mainly in winter as a result of the physiological restructuring of the organism before the beginning of the annual cycle of gonad formation. However, to determine the age of F. glaber, the spawning marks formed mainly in summer need to be considered. The proposed scheme for determining the developmental stages and age of F. glaber individuals is a valuable tool for studying the species and can help resolve a variety of ecological and conservation issues.

Karadeniz suları Shabla Burnu yakınlarından yakalanan deniz tarağının (Flexopecten glaber) iç organlarının histolojik yapısı

Assessing the possibility for cultivation of the smooth scallops (Flexopecten glaber) along the Bulgarian Black Sea coast requires a form one side very good knowledge of the biology of species, and from the other side internal organs and reproductive tissues, also the changes occurring during reproductive processes. Thus, the study aimed to investigate and evaluate the histological structure of the internal organs of the Flexopecten glaber caught in the Black Sea. Three samples were collected in June 2022 from commercial fishing in Black Sea waters near Cape Shabla. The shell length and weight of each mussel were measured and recorded. The study was carried out by making histological preparations of gonads and internal organs in adult smooth scallops. Histologically organs of smooth scallop showed that the tissues were in normal cytological condition. The microscopic analysis showed that the heart is located dorsal to adductor muscle. The kidneys are situated in the anterior margin together with gonads which cover the last one. Ventral to the gonad are attached pairs of gills. The histological structure of the gonads and internal organs of scallops was identified and described. The results of the current investigation expand the field of knowledge on the anatomy and histology of smooth scallops.

Long-term Variations in the Black Sea Population of Smooth Scallop, Flexopecten glaber (Linnaeus, 1758) (Bivalvia: Pectinidae): A Review

Data on the presence and characteristics of smooth scallop Flexopecten glaber (Linnaeus, 1758) aggregations in various parts of the Black Sea shelf (BSS) have been subjected to a retrospective analysis. The waters of the northern (Crimean coast), eastern (Central and North Caucasian), and Anatolian sectors of BSS can be considered the most favorable habitats for smooth scallop, where massive beds of this species were found in the first half of the 20th century. However, no such data are available for the northwestern and western BSS, where freshwater discharges from the Danube, Dniester, and Dnieper form a permanent zone of lower water salinity. The period of decline in the Black Sea scallop population recorded in the 1970s–1990s generally coincided with the well known ecological crisis due to the anthropogenic eutrophication of the Black Sea in the second half of the 20th century. In the late 2000s and the 2010s, the scallop beds in the Crimean BSS showed a tendency to recover, which may be associated with the general improvement of the ecological condition of the Black Sea basin. A similar recovery of scallop beds is expected to occur in the eastern (North and Central Caucasian) and southern BSS, but has not yet been recorded. The results obtained suggest a possibility of downgrading the conservation status of this species in the Red Data Books of the City of Sevastopol and the Republic of Crimea from the `species declining in abundance` to the `species recovering in abundance and distribution`.

Spat efficiency of the smooth scallop Flexopecten glaber in the Aegean Sea, Türkiye

This study was carried out to determine the spat efficiency of the smooth scallop Flexopecten glaber (Linnaeus) in surface and bottom water at the Ozbek coast (Türkiye) of the Aegean Sea from September 2017 to August 2018. The environmental parameters (temperature, salinity, chlorophyll-a, and total particulate matter) were also monitored at two depths. The average water temperature at the surface and bottom were 19.79 ± 5.62°C and 19.73 ± 5.24°C, respectively. The lowest chlorophyll-a values were recorded in February (1.12 g l-1) and June (1.23 µg l-1) at the surface and bottom, respectively. The highest chlorophyll-a value was recorded in August at both depths. Throughout the study, the number of F. glaber on the collectors was 270.33 ± 43.54 spat m-2 and 145.66 ± 18.03 spat m-2 were detected on the bottom collectors. A statistically significant difference was found between the growth of the spat attached to the surface and bottom collectors (p < 0.05).

Impacts of engineered iron nanoparticles on oxidative stress, fatty acid composition, and histo-architecture of the smooth scallop Flexopecten glaber.

Engineered iron nanoparticles are widely used in environmental remediation, yet their potential toxic effects on marine biota remain poorly elucidated. This study aimed to gain insight into the nanoscale zero-valent iron (NZVI) toxicity mechanisms for marine invertebrates. Aside from the effect on oxidative status and histopathology, the effect of NZVI on lipid metabolism in bivalves was studied for the first time. To this end, specimens of Flexopecten glaber were exposed to ascending concentrations (0.5, 1, and 1.5 mg/L) of NZVI for 96 h. Results illustrate differential patterns of iron accumulation in the gills and the digestive gland. By increasing NZVI concentrations, the total iron level tended to markedly increase in the gills and decrease in the digestive gland, reaching 132 and 37.6 μg/g DW, respectively, in the specimens exposed to 1.5 mg/L. Biochemical and cellular biomarkers highlighted that NZVI caused oxidative stress (measured as hydrogen peroxide, malondialdehyde, and advanced oxidation protein product levels) and alterations of antioxidant defense systems, including reduced glutathione, non-protein thiol, glutathione peroxidase, superoxide dismutase, and catalase. Modulation of lipid metabolism with changed fatty acid compositions (mainly an increase in the saturation and a decrease in unsaturation levels) was also observed in both gills and digestive gland. Moreover, several histological damages, including lipofuscin accumulation, infiltrative inflammations, and digestive tubule alterations, were observed in the two studied organs, providing supplementary evidence regarding the toxic effect of NZVI. This study adds to the growing body of evidence pointing to the hazardous impacts of iron NPs on aquatic ecosystems.

Assessment of the heavy metal levels and biomarker responses in the smooth scallop Flexopecten glaber from a heavily urbanized Mediterranean lagoon (Bizerte lagoon).

Marine heavy metal pollution is a worldwide serious issue. Like almost all Mediterranean lagoons, the Bizerte lagoon is highly urbanized and suffers from intensive anthropogenic pressure. In the present study, we screened the metal contamination and biomarker responses in the smooth scallop Flexopecten glaber inhabiting this vulnerable ecosystem. To this end, the concentrations of six heavy metals (HM) (i.e., Cu, Pb, Zn, Cd, Hg, and Fe) and a panel of biochemical endpoints including malondialdehyde (MDA), metallothioneins (MT), reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were determined in the gills and digestive gland across seasons (warm and cold) and sites (S1 and S2). The distribution of almost all analyzed metals in F. glaber tissues varied significantly between sites, seasons, and organs. The highest levels were recorded at S2 during the warm period. Moreover, the digestive gland was found to accumulate greater concentrations of HM than the gills. Marked spatio-temporal variations were also observed for oxidative stress biomarkers, mainly in the gills, while the digestive gland seems to be rather sensitive to seasonal variability. Particularly, we noticed that among the used biomarkers, MT did not show significant variations in the two tested organs across seasons and sites. From the obtained results, F. glaber appears as a sensitive organism to anthropogenic metal contamination and can be proposed as a promising bioindicator species for marine pollution.

Glyphosate exposure modulates lipid composition, histo-architecture and oxidative stress status and induces neurotoxicity in the smooth scallop Flexopecten glaber

Glyphosate is the most sprayed pesticide across the globe. Its toxicity to non-target marine organisms has recently piqued the scientific community's interest. Therefore, the purpose of this study is to investigate the potentially toxic effects of glyphosate on scallops, an ecologically and economically important bivalve group. To do that, specimens of the smooth scallop Flexopecten glaber were exposed to different concentrations (10, 100, and 1000 μg L−1) of the technical-grade glyphosate acid (GLY) for 96 h. The detrimental effects of this pollutant were assayed at cellular and tissular levels. The obtained results showed that the GLY was able to induce oxidative stress in the gills and the digestive gland of F. glaber as revealed by the enhanced hydrogen peroxide (H2O2), protein carbonyls (PCO), malondialdehyde (MDA), and lipid peroxides (LOOH) levels and the altered antioxidant defense system (the glutathione GSH content and the superoxide dismutase (SOD) activity). Additionally, GLY was found to alter the fatty acid profile, to exert a neurotoxic effect through the inhibition of the acetylcholinesterase (AChE) activity, and to provoke several histopathological damages in the two organs studied. The obtained results revealed that the pure form of GLY may exert toxic effects on F. glaber even at relatively low concentrations.

Settlement of Bivalve Spat on Artificial Collectors (Net Bags) in Two Commercial Mussel Parks in the North-Western Adriatic Sea

Among aquaculture activities, shellfish culture is considered more sustainable and beneficial in terms of food security. Currently, only a few bivalve species are reared and there is a need to explore the possibility to introduce new candidates for shellfish farming. Due to the lack of information on bivalve recruitment in the North-Western Adriatic Sea, in this study, the possibility to collect natural spat of commercial species was investigated. Artificial collectors (net bags) were deployed in two sites, Pellestrina and Caleri (North-Western Adriatic Sea), within two commercial mussel parks, during the spring–summer and summer–autumn periods. At both sites, collectors were placed at a distance of 1 m from each other, from 5 to 14 m depth. The influence of season, site and depth on bivalve recruitment was inspected and the presence of invasive species was also evaluated. In all, 28 bivalve taxa were found, and a higher settlement rate was observed in summer–autumn compared to the spring–summer period. Mytilus galloprovincialis, Flexopecten glaber, Mimachlays varia and Aequipecten opercularis were the most abundant species in spring–summer. In the summer–autumn period, in both sites analysed, a very high quantity of Anadara transversa and F. glaber were found. Indeed, these species were dominant at Pellestrina and Caleri, respectively. Another non-indigenous species, Arcuatula senhousia, was also detected. Relevant amounts of Pectinidae spat, F. glaber in particular, were collected and the optimal depth range for the scallop spat collection was found to be between 8 and 14 m. Our results highlight the relevant potential of Pectinidae spat collection along the North-Western Adriatic coasts, even though the presence of invasive species needs to be monitored.

Çardak Lagünü’ndeki (Çanakkale Boğazı, Türkiye) deniz tarağının Flexopecten glaber (Linnaeus, 1758), mikro ve makro element kompozisyonundaki aylık değişimler

The present study investigated the total elemental composition (Fe, Cu, Mn, Zn, Al, S, B, Na, Mg, K, Ca, P, S) in smooth scallop (Flexopecten glaber) meat collected monthly in the Çardak Lagoon (Turkey) in 2017- 2018. Considering the distribution of elements in terms of quantity during the year, the elements were sorted as S> Na> K> P> Mg> Ca> Fe> Zn> Mn> Al> B> Cu> Se and the heavy metals were below the detection limit. Although the elements were at their highest values during autumn and summer, they were at their lowest values during spring and winter. The differences between the months in terms of Fe, Mn, Mg, and Ca elements were found to be statistically significant (p <0.05). It was determined that the element composition of smooth scallop meat was suitable for consumption in terms of the area where it is collected and is beneficial for health when consumed in the amounts recommended by FAO/WHO, and CODEX. The Hazard Quotient (THQ) and the Hazard Index (HI), which was conducted to evaluate the health risks of consuming smooth

Growth and Survival Performance of Smooth Scallop (Flexopecten glaber Linnaeus, 1758) at Different Depths in the Aegean Sea

This study was conducted between July 2016 and 2017 to determine the growth and survival rates of the smooth scallop Flexopecten glaber spats in Urla Karantina Island. The sea water temperature was determined as 21.56±6.33°C, 21.1±6.40°C and 20.87±6.35°C at 2, 4 and 6 m depths, respectively. Salinity values varied between 36 and 38.19 PSU in the region. The highest chlorophyll-a value was determined as 8.95 µg l-1 in August at 2 m depth and 1.65 µg l-1 as the lowest at 4 m depth in January. Average values of total particulate matter amount were calculated as 4.41±1.86 mg l-1, 5.09±1.88 mg l-1 and 5.47±1.89 mg l-1 at 2, 4 and 6 m depth, respectively. Scallop spats with an average height of 8.26±1.55 mm were measured at the beginning of the study. The heights of the smooth scallop spats, which were placed at 2 m, 4 m and 6 m depths in the study area, were 42.6±1.11 mm, 41.53±12.85 mm and 41.57±1.64 mm and their weights were measured as 12.71±0.89 g, 12.85±0.53 g and 12.82±1.00 g, respectively. While the survival rate was 53% placed at 2 m depth in the study area, the lowest survival rate was found as 37% for the spats grown at 6m depth. The result showed that the mean values of height at the surface depth (2 m) were more significant than those at the other depths (4 m and 6 m). However, there were no statistically significant differences between the depths and specific growth rate (SGR) for height and weight (p>0.05). But SGRh and SGRw values at each depth showed statistically significant differences between months (p<0.05).

Growth and morphometric characteristics of the scallop <i>Flexopecten glaber </i>(Bivalvia: Pectinidae) reared in cages off the coast of Crimea (Black Sea)

The spat of the scallop Flexopecten glaber were collected in cages with the Pacific oyster Crassostrea gigas cultured on a mussel-and-oyster farm (outer roadstead of Sevastopol Bay). For two years they were reared in plastic cages at a depth of 2-3 m. The cages were periodically withdrawn to measure the size and weight parameters of the molluscs: the length (L, mm), height (H, mm), and width (D, mm) of shells and the total live weight (W, g). The correlations among the parameters under study are presented. The changes in the indices of the frontal (D/L) and sagittal (H/L) curvatures, convexity ((H+D)/L) and conditional volume (H×D×L/1000) of the shells in ontogenesis are shown. Upon reaching a shell length of 30-35 mm, the allometry of the volumetric and weight growth of molluscs changed from positive to negative. The largest values of the shell convexity index were registered in thesame length range. A conclusion about the interval-type growth of F. glaber in linear size and weight is made. It is suggested that the optimal strategy of shell formation in F. glaber in ontogenesis implies the ripening and the first reproduction of the molluscs occurring at the highest volumetric characteristics of the shell. The relationships for the linear size and weight growth ofF. glaber in the first two years of life are obtained. It is concluded that the scallop F. glaber should be considered as a possible element for the diversification of the existing aquaculture of molluscs (mussels and oysters) off the coast of Crimea.

Strategies for Successful Scallops Spat Collection on Artificial Collectors in the Taranto Gulf (Mediterranean Sea)

The high variability in natural recruitment of Pectinidae is a common feature of many marine invertebrates with a pelagic larval stage, but may negatively affect aquaculture activities. Detailed information on settlement patterns and spat availability is required to reduce costs and labor. In this regard, we attempted to establish the precise immersion time and the deployment dates for spat collectors in the Taranto Gulf (Mediterranean Sea, Italy). The first experiment was carried out from June to October 2013, deploying collectors every 15 days and retrieving them after 4, 6, 8, and 10 weeks. Results from the first experiment allowed us to select 8 weeks as the best immersion time for spat collection. The second experiment was carried out from June 2013 to July 2014 when we deployed spat collectors every 15 days and recovered them after 8 weeks to detect the favorable periods to place the collectors in water to obtain the highest scallop spat harvest rate. Mimachlamys varia was the most abundant pectinid (greater than 90%), whose recruits were collected during most of the year studied, followed by Flexopecten glaber with the highest rates in July (87%) and Pecten jacobaeus, which never exceeded 17% of collected spat. M. varia had a long recruitment period (from October to early June), F. glaber showed a high number of spat during autumn months and from June to July while P. jacobaeus showed a restricted period of spawning. Our experiments provide useful insights into strategies for establishing scallop aquaculture in order to promote these mollusks as alternative candidates for aquaculture farming in the area.

Size and Age Characteristics and Phenotypic Peculiarities of Somatic Growth of the Black Sea Mollusk Flexopecten glaber ponticus (Bivalvia, Pectinidae)

This paper presents a preliminary analysis of the morphological, physiological, and biochemical parameters of somatic growth in the Black Sea scallop, Flexopecten glaber ponticus Bucguoy, Dautzenberg et Dollfus 1889, from a coastal site near Sevastopol, Crimea. The species is one of the few marine Black Sea mollusks listed in the Red Book of Sevastopol and Crimea with the status “Diminishing in numbers.” The peculiarities of soft tissue somatic growth have been studied in three size groups differing in linear diameter: 13–17, 21–24, and 25–30 mm. An analysis of the total RNA in tissue homogenates has shown that the rate of protein synthesis in the first and second groups (under-yearlings) is 1.2–1.5 times higher compared to adults. The population reveals seven color morphs (phenotypes). Three phenotypes (beige, violet, and gray-and-brown) are characterized by high-level protein synthesis. Mollusks of a mixed “multi” phenotype have the lowest level of tissue biosynthesis, usually being 2.5 times lower than that for other morphs. The results obtained indicate that the growth processes are linked to the color of the mollusk shell. High direct correlations between the weights of the total wet mass and the tissue mass observed in all mollusk groups may be evidence of positive growth allometry.

Comparative Characteristics of Percentage Edibility, Condition Index, Biochemical Constituents and Lipids Nutritional Quality Indices of Wild and Farmed Scallops (Flexopecten glaber)

The consumption of seafood has considerably increased over recent decades; however, as wild seafood stocks are limited, the cultured ones represent a possible valuable alternative. The purpose of this study was to compare wild and cultured scallops, Flexopecten glaber, on the basis of their marketability indices and biochemical characteristics. Wild and cultured specimens were harvested from the Ionian Sea (the Central Mediterranean Sea). Protein and lipid were significantly different between scallops, with the values of protein of 8.50 and 11.6 g/100 g and lipid of 1.45 and 1.70 g/100 g for wild and cultured scallops, respectively. Regarding fatty acids (FAs), statistical differences were also detected. The cultured species showed significantly (p < 0.05) higher polyunsaturated fatty acids (PUFAs) than its wild counterpart. Eicosapentaenoic (EPA, 20:5 n3) and docosahexaenoic acid (DHA, 22:6:3) were the major polyunsaturated fatty acids, although only DHA showed significant differences between wild and culture scallops (p < 0.05). The ratio of n3/n6 PUFA showed high values, with 2.7 and 3.1 for wild and cultured scallops, respectively. The atherogenic and thrombogenic indices and hypocholesterolemic/hypercholesterolemic fatty acid ratio indicated an import role in human diet. The appreciated nutritional properties of this species could support the interest to promote its cultivation, ensuring high food nutritive value for the purchasers.

New data on the morphological variability of the shell of <i>Flexopecten glaber </i>(Linnaeus, 1758) (Bivalvia, Pectinidae) in the Black Sea

The morphological variability of the bivalve mollusc Flexopecten glaber was studied based on the analysis of 306 specimens from the Kazach’ya Bay (Sevastopol, Crimea) of the Black Sea. The sampling of mollusks was carried out with the help of skuba equipment in June-September of 2017-2018. For F. glaber, the age and size characteristics are given and the main trends in their ratios with the shell growth are considered. For the first time, quantitative indicators of thickness of the shell valves, their weight and height of the radial ribs are presented and discussed. A wide intraspecific polymorphism of the shell is shown in a relatively narrow range of habitat conditions. The obtained data expand the understanding of the morphological variability of F. glaber in the Black Sea and provide new information on the functional morphology of the species.