Turkish Black Sea Coast Research Articles

Structure and Dynamics of Phytoplankton Populations in the Black Sea from 2014 to 2017

This study investigated the seasonal variations in phytoplankton communities along the Turkish Black Sea coast (2014-2017). Analyzing data from 20 stations revealed high biodiversity (175 species across 14 classes). Phytoplankton abundance showed distinct seasonality, with a peak in summer (2017, 96.6%) and lows in winter, characterized by dinoflagellate dominance. In terms of biomass, diatoms dominated in half of the sampling seasons, while dinoflagellates dominated in the other half at the surface during the study period. The dominance of dinoflagellates corresponded to the winters and summers of 2015 and 2016. The winter conditions of 2015 were harsh. The surface water community composition sometimes varied from that of the water column. Importantly, 44 potentially toxic species were identified, comprising 25% of the community and significantly contributing to both abundance (73.2-98.6%) and biomass (64-90.2%) throughout the year. These results highlight the unique structure of the Black Sea phytoplankton community, characterized by seasonal dominance of diatoms and a significant presence of potentially toxic species. Season, year, and water depth significantly influenced the phytoplankton assemblages. Water temperature was negatively correlated with dissolved oxygen and nitrogen-based nutrients.

Evaluating the unexplored recreational fishing in the Turkish Black Sea: socio-economic significance and environmental impact

Marine recreational fishing, a globally popular outdoor activity, has deep cultural roots and ecological implications. This study, conducted between 2021-2022, explores marine recreational fishing practices along the Turkish Black Sea coast. It analyzes fisher numbers and demographics, fishing effort, fishing methods, and species caught and released. Furthermore, the research sheds light on the economic dimensions, emphasizing the substantial contributions of recreational fishing to local economies. Notably, responsible practices, such as catch-and-release initiatives, demonstrate anglers’ awareness of conservation efforts. Within the Turkish Black Sea region, an observed 18.5% participation rate among a population of 24.5 million implies the presence of approximately 4.5 million marine recreational fishers. Annually, this translates to nearly 30 million fishing days, accompanied by a total expenditure of 400 million Euros. However, it’s imperative to handle these figures cautiously as the timing of the screening survey during the COVID-19 pandemic may have influenced the high participation rate, introducing a potential bias. A detailed examination of a Turkish marine recreational fisher engaged in Black Sea fishing reveals an average annual catch of 16.5 kg of retained fish and 1.2 kg of released fish biomass. When extrapolated to the larger population of 4.5 million fishers, this culminates in a noteworthy landing biomass approaching 74,000 tons. The study unveils that marine recreational fishers in the Turkish Black Sea predominantly target commercially important species, resulting in a retained biomass surpassing commercial landings in 2021. This prompts concerns about potential impacts on crucial commercial fish stocks, underscoring the imperative inclusion of recreational fisheries in stock assessments. The research, providing essential insights into the intricate dynamics of recreational fishing, lays a foundation for well-informed policies and practices that concurrently promote environmental conservation and the continuation of this valued leisure activity.

First record of Sebastes schlegelii Hilgendorf, 1880 along the Turkish Black Sea coast – new addition to the alien species inventory

Sebastes schlegelii is a typical bottom dwelling boreal species, whose native distribution range includes Japan, Korean peninsula and China. This northwest Pacific originated species has recently been recorded from the Crimean and Caucasian coast (northern Black Sea), whose introduction was assumed to be either by balast waters or the acclimatization of Crassostrea gigas (Pacific oyster). On 16 August 2023, a single S. schlegelii specimen with 20.6 cm standard length and 282.1 g in weight was captured off Ünye, Ordu coast (southeastern Black Sea), which was previously an unreported fish from the Turkish marine waters. Detailed morphometric and meristic characteristics are presented in the paper, and species identification was further confirmed by genetic analysis. Available information reveals this alien species to be fished regularly, although in small quantities, indicating a presumably established population in the region. The species should be treated as a potentially invasive fish, since it may negatively influence to the local biodiversity through interspecific competition. Close monitoring of its existing population is strongly suggested.

Craspedostaurosnazmii sp. nov., a new diatom species (Bacillariophyta) from the Turkish Coast of the Black Sea.

Craspedostauros E.J. Cox is a diatom genus comprising 17 taxa reported from various regions of the world. While many species of Craspedostauros are epibiontic, the taxa have variable ecological preferences. In this study we formally describe Craspedostaurosnazmiisp. nov., an epilithic species discovered along the Turkish Black Sea Coast, based on light and scanning electron microscopy. Craspedostaurosnazmiisp. nov. is characterized by valves that are lanceolate to narrowly lanceolate, slightly constricted near the apices with uniseriate, parallel throughout the whole valve, transapical striae and and the presence of an apical silica flap. The areolae are distributed over the valve face and the mantle. The differences and similarities between C.nazmiisp. nov. and established species of Craspedostauros are discussed. Based on shape and morphometrics, the most similar species is Craspedostauroscapensis, but it is easily distinguished from C.nazmiisp. nov. by its lack of an apical silica flap.

Integrated assessment of eutrophication in the southern Black Sea waters, using the Nested Environmental Status Assessment Tool

This research deals with the land-based pressures on the southern Black Sea coast (Turkey), with the objective of assessing their eutrophication impacts. In this context, reference values of some of the eutrophication indicators were calculated, and eutrophication assessment was carried out for this area using the holistic approach NEAT (Nested Environmental Status Assessment Tool). In addition, correlations between NEAT results of coastal regions and pressure-impact analysis methods were investigated. In the determined Spatial Assessment Unit (SAU) areas, 9 indicators were evaluated according to the SAU surface, both with and without weighting by their size the overall assessment of the Turkish Black Sea coast is good (0.70) and moderate (0.57) environmental status, for non-weighting and weighting by SAUs, respectively, with a high confidence level. With this study, we concluded that the sensitivity of the assessment tool needs to be increased. Despite these results, an appropriate number of indicators to represent the water column should be added. It is important to include the phytoplankton variable in the evaluation in future studies. In addition, this study, which uses NEAT allows identifying problematic environmental areas that require attention and action from managers and policymakers.

First Report of <i>Aphanurus stossichii</i> (Digenea: Hemiuridae) from <i>Engraulis encrasicolus</i> on the Turkish Coast of the Black Sea, with Light and Scanning Electron Microscopic Observations

The aim of this study is to investigate in detail the morphological features of the digenean parasite Aphanurus stossichii isolated from the European anchovy Engraulis encrasicolus using light and scanning electron microscopy (SEM). The specimens of A. stossichii were obtained from the pharynx and stomach of the European E. encrasicolus caught by commercial fishing vessels in the Black Sea. Parasites were killed in a hot normal saline solution, preserved in to 70% ethanol for light microscopic (LM) studies, and in 2.5% glutaraldehyde for SEM. The morphological diagnostic features of A. stossichii were studied in detail under both LM and SEM. The morphological characteristics of the examined adult A. stossichii specimens were found to be similar to the original descriptions describing the basic characteristics of forebody and hindbody shape, the position and shape of the vitellarium, ovary, and and testes, and the shapes of oral and ventral sucker. The measurement data for all morphological diagnostics were provided; photomicrographs of each part of the parasite were presented. Infection prevalence, mean intensity and mean abundance values were 8.89%, 4.5 and 0.4, respectively. All available records of A. stossichii morphology are based on light microscope, this is the first study to identification the morphological features of the parasite with SEM. This research is the first on A. stossichii presence in E. encrasicolus on the Turkish Black Sea coast.

New records of gastropods (Caenogastropoda and Heterobranchia) from the Turkish coasts with observations on some poorly known species

This work presents information about 19 taxa recorded from different habitats at depths between 0.2 and 508 m in the last two decades, which are new records or poorly known species along the Turkish coasts. Among the identified species, Epitonium vaillanti, Melanella cf. lubrica, Melanella monterosatoi, Pelseneeria minor, Setia amabilis, Kurtziella serga, Rissoella diaphana, Rissoella inflata, and Spirolaxis clenchi are new records for the Turkish mollusc fauna, Eatonina pumila is new report for the Turkish coast of the Aegean Sea, and Eatonina ochroleuca, Acirsa subdecussata, Lamellaria latens, Setia pulcherrima, Setia valvatoides, and Turbonilla cangeyrani are species with rare distribution which were sampled for one or a few times only. Viriola cf. bayani, Acirsa subdecussata, Melanella monterosatoi, Eatonina ochroleuca, E. pumila, Setia amabilis, Setia pulcherrima, Lamellaria latens, Rissoella diaphana, R. inflata, and Syrnola sp. were encountered along the Aegean Sea coast, whereas Epitonium vaillanti, Pelseneeria minor, Rissoidae sp., Kurtziella serga, Turbonilla cangeyrani, and Spirolaxis clenchi were recorded on the Levantine coast of Turkey, and Melanella cf. lubrica in the prebosphoric region of the Sea of Marmara. Setia valvatoides is the only species found on the Turkish Black Sea coast. On the other hand, Epitonium vaillanti and Viriola cf. bayani are species originated outside the Mediterranean basin. Most of the species were found at infralittoral and circalittoral depths, except for Kurtziella serga and Spirolaxis clenchi found at a depth of 508 m. The present study elucidates some ecological and distinguishing characteristics of the investigated species, along with their colour photographs and distribution along the Turkish coasts.

Molecular and morphological description of Myxidium parvum (Cnidaria) from Salaria pavo (Blenniidae) in the Black Sea.

Members of the predominantly coelozioc genus Myxidum Bütschli, 1882 with more than 232 species have been reported from a wide variety of marine and freshwater fish species worldwide. In this study, 25 specimens of peacock blenny, Salaria pavo, were collected from Sinop on the Turkish Black Sea coast. The gills, fins, skin, urinary bladder, gal bladder, kidney, liver, gonads and smooth muscle tissue of the collected samples were investigated for myxosporean parasites. Myxidium parvum Yurakhno, 1991 was the only myxosporean found in the gall bladder of host fishes. Based on spore morphology, M. parvum had mostly overlapping measurement data of original description in spore length and width, polar capsule length but differed slightly in width; however, they were within the ranges previously reported from other blenniid host fish species in the Black Sea. Moreover, in this study, molecular analysis of the 18S rDNA gene of M. parvum isolates from S. pavo was done for the first time and our M. parvum genotypes appeared as sister to Myxidium incurvatum within the "Lineage II" of the marine Myxidium clade.

Molecular and morphological description of Ceratomyxa scophthalmi sp. nov. (Myxozoa) infecting Scophthalmus maeoticus and first report of Myxidium finnmarchicum in the Black Sea.

In the present study, 2 species of myxozoan parasites, the novel Ceratomyxa scophthalmi sp. nov. and Myxidium finnmarchicum, were documented from the gallbladder of Scophthalmus maeoticus inhabiting the Turkish Black Sea coast at Sinop. C. scophthalmi sp. nov. had mostly spherical, clavate, and fine-grained polymorphic plasmodia that ranged in diameter from 16.0 to 29.0 µm. Spores were arcuate with a convex anterior margin and concave posterior. Valves of spores were highly elongated and unequal in thickness with one valve 1.1-1.3 times thicker than the other. Valves narrowed gradually toward slightly truncated ends. The mean (range) dimensions of spores were 9.4 (8.5-10.0) µm in length and 49.6 (44.5-55.0) µm in thickness, with polar capsules that were 3.1 (2.7-3.5) µm in length and 3.2 (2.7-3.5) µm in width. Polar filaments were coiled with 4-5 turns. Large numbers of immature forms of C. scophthalmi sp. nov., which were often 'crumpled', and mature forms were found together in the gallbladder bile. Along with morphological differences, phylogenetic analysis based on 18S rDNA, including pairwise nucleotide similarities with other related Ceratomyxa species, suggests C. scophthalmi as a novel species. Moreover, this report provides the first morphological and molecular descriptions of M. finnmarchicum outside of its original geographical location and type host species.

Using acoustically visible gillnets to reduce bycatch of a small cetacean: first pilot trials in a commercial fishery

Bycatch of protected species, particularly small cetaceans, in gillnets is a worldwide concern. One hypothesis for this is that echolocating cetaceans entangle because they do not perceive conventional gillnets as impenetrable barriers, owing to the gillnet’s faint echo. A gillnet modified for improved acoustical visibility was tested in a first pilot trial in a commercial gillnet fishery targeting turbot (Scophthalmus maeoticus) on the Turkish Black Sea coast. This study is the first demonstration of the viability of using a gillnet equipped with small acrylic glass spheres to reduce bycatch of harbor porpoises in a commercial fishery and provides the basis for full-scale sea trials of the gear in commercial fisheries through a power analysis. In these pilot experiments, the focus lied on the handling of the gear and identification of requirements for a full-scale trial, but results include promising bycatch data for an endangered echolocating marine mammal (Phocoena phocoena) and no reduction in catch efficiency of a bottom-dwelling, vulnerable species (Raja clavata).

Digenean Parasites of Labrid Fishes (Labridae: Symphodus) from Turkish Coasts of the Black Sea: New Records

In the present study digenean parasite faunas of four labrid fishes, Symphodus tinca, S. rossali, S. cinereus and S. ocellatus were investigated and compared. A total of 52 fish specimens were caught on the Black Sea coast near Sinop, Turkey, over two years. Eight digenean species were found in the four labrid fishes. These are Helicometra fasciata, Gaevskajatrema perezi, Proctoeces maculatus, Phyllodistomum crenilabri, Galactosomum lacteum, Condylocotyla pilodora, Metadena pauli and Opecoelidae gen. sp. Each digenean species on their respective hosts were counted, their prevalence, mean intensity and abundance values were determined. While the maximum parasite diversity was found in S. tinca, S. ocellatus was infected with the fewest parasites. Total parasite abundance was significantly high in S. roissali, which was infected with four species. A close resemblance was observed in the digenean parasite faunas of S. tinca and S. roissali. The core, secondary, satellite, and rare species in the digenean parasite community of each host were determined. This study contains the first data on the digenean parasites of labrid fish on Turkish Black Sea coast. Phyllodistomum crenilabri and Metadena pauli are new parasite records in Turkish fish parasite fauna, while Condylocotyla pilodora is a new parasite record for the labrid fishes.

Population genetic structure of turbot (Scophthalmus maximus L., 1758) in the Black Sea.

Turbot, Scophthalmus maximus, is a commercially important demersal flatfish species distributed throughout the Black Sea. Several studies performed locally with a limited number of specimens using both mitochondrial DNA (mtDNA) and microsatellite markers evidenced notable genetic variation among populations. However, comprehensive population genetic studies are required to help management of the species in the Black Sea. In the present study eight microsatellite loci were used to resolve the population structure of 414 turbot samples collected from 12 sites across the Black Sea. Moreover, two mtDNA genes, COI and Cyt-b, were used for taxonomic identification. Microsatellite markers of Smax-04 and B12-I GT14 were excluded from analysis due to scoring issues. Data analysis was performed with the remaining six loci. Loci were highly polymorphic (average of 17.8 alleles per locus), indicating high genetic variability. Locus 3/20CA17, with high null allele frequency (>30%), significantly deviated from HW equilibrium. Pairwise comparison of the FST index showed significant differences between most of the surveyed sampling sites (P < 0.01). Cluster analysis evidenced the presence of three genetic groups among sampling sites. Significant genetic differentiation between Northern (Sea of Azov and Crimea) and Southern (Turkish Black Sea Coast) Black Sea sampling sites were detected. The Mantel test supported an isolation by distance model of population structure. These findings are vital for long-term sustainable management of the species and development of conservation programs. Moreover, generated mtDNA sequences would be useful for the establishment of a database for S. maximus.

Morphological and molecular descriptions of Sphaeromyxa sevastopoli (Cnidaria) from host fishes from Sinop on the Black Sea coast.

Members of the genus Sphaeromyxa Thélohan, 1892 have been reported from a wide variety of fish species worldwide. In the present study, specimens of rusty blenny, Parablennius sanguinolentus, collected from Sinop on the Turkish Black Sea coast were investigated for myxosporean parasites by using both conventional and molecular methods. Sphaeromyxa sevastopoli Naidenova 1970 was the only myxosporean parasite found in the gall bladder of host fishes. The morphology peculiarities of obtained S. sevastopoli spores are in good agreement with those of original description and the morphometric data overlapped in spore length and width but differed in polar capsule length and width; however, they were within the ranges previously reported from 18 host fish species. Moreover, in the present study, molecular analysis of the 18S rDNA gene of S. sevastopoli isolate in our P. sanguinolentus as well as isolates from shore rockling Gaidropsarus mediterraneus and knout goby Mesogobius batrachocephalus which were previously morphologically identified and reported by Okkay and Özer (Acta Zool Bulg 72(1):123-130, 2020) was done for the first time and our three S. sevastopoli genotypes were allocated to the "balbianii" group which is characterized by straight or slightly curved and fusiform or ovoid spores with ovoid polar capsules.

First molecular data on the validity of Myxobolus ichkeulensis (Cnidaria: Myxosporea) from Mugil cephalus (Mugilidae) in Turkish waters

To date, there is no report on molecular characterisation of Myxobolus ichkeulensis in Mugil cephalus (Mugilidae) in Turkish marine waters. The aim of the current research was to provide the first molecular data on M. ichkeulensis from M. cephalus in Turkish Black Sea coasts. A total of 40 M. cephalus specimens were examined for the presence of M. ichkeulensis in the Turkish Black Sea coasts during January 2017 and April 2017. In the present study, M. ichkeulensis was identified based upon the myxospore morphology, host and tissue specificity, and SSU rRNA sequence. Phylogenetic analysis using neighbor-joining also revealed that our isolate (#GZP-2018-Samsun1) was clustered with other Myxobolus species that infect M. cephalus. The current study includes the morphological and histopathological descriptions and first molecular data on M. ichkeulensis in M. cephalus in Turkish marine waters. M. ichkeulensis was also reported from the M. cephalus in the coast of the Black Sea in Turkey for the first time. Moreover, our current genetic data was recorded as the new valid SSU rRNA sequence (MH374629) for M. ichkeulensis in the GenBank database.

Red-flanked Bluetail Tarsiger cyanurus recorded at the Turkish Black Sea coast for the first time

On 21 October 2019, a Red-flanked Bluetail Tarsiger cyanurus (Pallas, 1773) was caught at Cernek Ringing Station in the Kizilirmak Delta on the Turkish Black Sea coast. This record is the third rec...

First Molecular Data on Myxobolus episquamalis (Myxozoa: Myxosporea) Infecting the Scale of Grey Mullet (Mugil cephalus) from Turkey

The aim of the present study was to show the morphologic and molecular characterization of Myxobolus species in grey mullet (Mugil cephalus) caught from the Black Sea coasts of Turkey. A total of 104 grey mullets caught from Turkish Black Sea coasts were obtained from fish markets between November 2017 and February 2018 and were examined for the presence of Myxobolus by using morphological and advanced molecular diagnostic methods. Totally, three out of 104 fish specimens were found to be infected with large and white coloured plasmodia and the prevalence was determined as 2.8%. The myxospores were morphologically identified as Myxobolus episquamalis, confirmed by using sequence analyses of their 18S rRNA gene regions. The shape of myxospores was oval and they were 8.6 (7.8-9.4) μm in length, 6.7 (6.1-7.3) μm in width and 4.7 (4.1-5.3) μm in thickness. Measuremenst of two pyriform polar capsules were 4.2 (3.7-4.6) μm in length ve 2.2 (2.1-2.4) μ m in width. The length of polar filament was determined as 27-51 μm. Nucleotide sequences of the 18S rRNA gene of the ES-2018-ERU isolate (MK012069) found in our study showed 99.8% and 100% similarity with M. episquamalis isolates submitted to GenBank from Tunisia (AY129312) and South Korea (JF810537; KC733437), respectively. Pairwise genetic distance (%) between ES-2018-ERU isolate and the other Myxobolus species which were identified in mullets from various countries were determined as 9.9-14.8%. Conclusion: This study provides first molecular This study provides first molecular data on M. episquamalis found in the scale of the grey mullets (Mugil cephalus) from Turkey.

Molecular characterization of Hysterothylacium aduncum (Nematoda: Raphidascarididae) larvae infecting Merlangius merlangus euxinus (Linnaeus, 1758) from the Turkish Black Sea coast based on mitochondrial small subunit ribosomal RNA gene analysis

The taxonomy of Hysterothylacium genus remains incomplete and unclear in Turkish waters. In the present study, H. adumcum larvae were morphologically identified from Merlangius merlangus euxinus in the Black Sea, Turkey. The nuclear ribosomal ITS regions (ITS-1, 5.8S subunit, ITS-2) and the small subunit of the mitochondrial ribosomal RNA (rrnS) gene of H. aduncum were amplified and sequenced. The BLAST analysis indicated that present ITS sequences of H. aduncum were identical to that of the reference sequence of H. aduncum (accession no JX413596) recorded previously from the Black Sea, Turkey. The present rrnS gene of H. aduncum from the Black Sea, Turkey (MK886768) showed 97.94 to 99.56% identity with isolates of H. aduncum from the Mediterranean Sea (MF000685-MF000691) and the Chinese waters (MF140344). Moreover, pairwise comparison between the rrnS sequences of the H. aduncum from the Black Sea, Turkey (MK886768) and others H. aduncum isolates from the Mediterranean Sea (MF000685-MF000691), the Chinese waters (MF140344) showed differences ranged from 0.2 and 1.7%. With the present study, H. aduncum from the Black Sea was characterized for the first time by sequencing of the mitochondrial rrnS gene.

Intraspecific Length Variation and Shell Thickness of the Ostracod Cyprideis torosa (Jones, 1850) as a Potential Tool for Palaeosalinity Characterization

Cyprideis torosa (Jones) is a common ostracod species in brackish waters of large parts of the world. The species appears in, but it is not restricted to, marginal marine areas, and it thus plays a significant role in identifying variable impacts between the marine and terrestrial realms as its carapace changes phenotypically under various conditions. This variability could be a highly valuable source of information in palaeoecology. We use valves of this species living in different lagoonal and lacustrine environments of the Kızılırmak Delta at the Turkish Black Sea coast since the Mid-Holocene. By measuring the valve sizes of adult individuals and A-1 instars and documenting the thickness classes of the adult shells we found a good positive correlation between the size of female valves and the prevailing salinity (correlation coefficient: 0.56), while such a correlation is lacking for ontogenetic stage A-1. No changes of the height/length ratio of the valves were recognizable along the salinity gradient. Shells are significantly thicker under relatively stable, higher saline conditions, but thinner in highly variable and low saline deltaic lakes. Both morphological features, size and shell thickness of C. torosa (Cyprideis torosa), are thus potential tools to give palaeo-environmental information, especially in C. torosa-dominated, low diversity marginal marine environments.

Feeding habits during migration of the Atlantic bonito Sarda sarda (Bloch, 1793) to the Black Sea

ABSTRACTInformation about food web dynamics is crucial for the success of ecosystem-based management. In order to collect such information, it is necessary to establish the dietary contents of species in the food chain. In this study, the diet of Atlantic bonito Sarda sarda (Bloch, 1793), one of the most important species in the Black Sea ecosystem, has been examined. The aim of this study was to investigate the prey preferences of Atlantic bonito over an eleven-year period during their feeding migration to the Black Sea. Sampling was carried out by commercial purse seine and gill nets along the Turkish Black Sea coast during migration of the Atlantic bonito from 2005 to 2016. Stomach contents were identified to the lowest possible taxonomic level. Atlantic bonito dietary composition was analyzed by fishing season, sex and size classifications. Results revealed a Vacuity Index value (V %) of 67% while 33% of individuals sampled had at least one prey species in their stomach content. Since S. sarda predominantly feed on small fish species, stomach contents contained mainly Engraulis encrasicolus, Trachurus mediterraneus, Sprattus sprattus, Mullus barbatus, Gobius niger, Merlangius merlangus, Pomatomus saltatrix, Alosa immaculata, Parablennius tentacularis and small unidentified prey items (tissue particles, … etc.). The most frequent prey item was E. encrasicolus with a percentage occurrence of 94%. In conclusion, the main prey species was determined as E. encrasicolus and statistical analyses of X2 was found significant (P < 0.005) according to year, sex and size.

A new sediment dwelling and epizoic species of Olifantiella (Bacillariophyceae), with an account on the genus ultrastructure based on Focused Ion Beam nanocuts

The marine diatom Olifantiella Riaux-Gobin et Compere predominantly occurs in tropical Indo-Pacific coral reef environments. The genus has about a dozen validly published taxa and is characterized by transapically elongate striae composed of a macroareola, broad perforated girdle, and tubular buciniportula process of trumpet-shape. The valve mantle of taxa related to the generitype, O. mascarenica, have a canal-shaped structure around the valve at the face / mantle junction, while those to O. gorandiana have a simple mantle or strongly narrow canal and complex buciniportula composed of hollow processes. The geographic distribution of Olifantiella is expanded in this study to include species observed in loggerhead sea turtles scrapes from the Aegean Turkish coast and samples from the Turkish Black Sea and Adriatic Sea coasts. Olifantiella has also been identified in Martinique Island, Caribbean Sea. A transfer of Navicula infirmitata is proposed due to the areola and buciniportula structure, as Olifantiella infirmitata. Further, an application of the Focused Ion Beam (FIB) to a sequential cutting of frustules allows resolution of Olifantiella mascarenica valve ultrastructure.