Being green in the Red Sea - the photosymbiotic ascidian Diplosoma simile (Ascidiacea: Didemnidae) in the Gulf of Aqaba

The photosymbiotic ascidian Diplosoma simile is characterized by a wide global distribution. The current study provides the first record of D. simile in the Red Sea, with remarks on its spatial distribution and phylogeny. Partial COI and 18S rDNA sequences of D. simile from the Red Sea revealed high similarity to those from the West Pacific, indicating a much broader range than previously recorded. In the Red Sea D. simile is common on natural coral reefs at depths ranging from 1–35 m. Diplosoma simile colonies were found to overgrow and would appear to suffocate several species of live stony corals, though this does not appear to cause mass coral mortality in the Red Sea, unlike that recorded in other locations.     

On genetic differentiation of the Pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> tilesius, 1810 (Gadiformes: Gadidae)

The variability of the Gmo3, Gmo34, Gmo35, and Pgmo32 DNA microsatellite loci in Pacific cod Gadus macrocephalus samples from different areas of the North Pacific was analyzed. The data obtained show that Pacific cod from the southern Kuril Islands significantly differs from the populations of the Bering Sea, the Sea of Okhotsk, and the coastal waters of Canada (the microsatellite loci Gmo3 and Pgmo32 bear the highest differentiating capacity). Despite the significant geographical remoteness of these areas from one another, the above three Pacific cod populations exhibit a high degree of similarity (I = 0.997–0.999).     

Diet composition of the juvenile chub mackerel (Scomber japonicus) in the Aegean Sea (Izmir Bay, Turkey)

Stomach contents of 296 juvenile chub mackerel (Scomber japonicus Houttuyn, 1782) specimens were examined based on samplings carried out in Izmir Bay (Aegean Sea, Turkey) during 2001. In terms of percentage weight (W%), fishes were the main food during summer and autumn. Thaliaceans (Salpa sp.) constituted the most important food source in winter, whereas planktonic crustaceans (Amphipoda, Copepoda) were the main prey during spring. According to the Bray–Curtis similarity index, diet of the chub mackerel was 64.1% similar during the summer, winter and autumn seasons.     

The karyotype of the flathead sculpin Megalocottus platycephalus platycephalus (Pallas, 1814) (Pisces: Cottidae) from Odyan Bay,Sea of Okhotsk

This study deals with the karyotype of the flathead sculpin Megalocottus platycephalus platycephalus (Pallas, 1814) (family Cottidae) from Odyan Bay of the Sea of Okhotsk. The karyotype is stable: 2n = 42 (2 metacentric, 2 submeta-subtelocentric, 30 subtelocentric, and 8 acrocentric chromosomes), NF = 44 + 2. The nucleolar organizers (NOs) were identified using Ag-banding in the telomere parts of the short arms of two large subtelocentric chromosomes. Variations in the number of nucleolar organizer chromosomes and in the number of NO-staining blocks were found. Comparison of the karyotype of M. p. platycephalus with the karyotypes of previously studied species of the genus Myoxocephalus from the Sea of Japan and the Sea of Okhotsk revealed their significant similarity in the main features and difference in the number and localization of NORs.     

Upwelling and eddies affect connectivity among local populations of the goldeye rockfish,Sebastes thompsoni (Pisces,Scorpaenoidei)

The goldeye rockfish, Sebastes thompsoni, commercial rockfish catch in the Northwest Pacific Ocean, may influence its population structure. To clarify the population genetic structure of Korean S. thompsoni and its degree of hybridization with the most close species, Sebastes joyneri, we analyzed a mitochondrial (mt) DNA control region and eleven polymorphic microsatellite (ms) loci. S. joyneri individuals were clearly distinguished from S. thompsoni by the mtDNA control region and ms loci results, with single interspecific hybridization between two species suggesting no impact on genetic structure of S. thompsoni. Analysis of mtDNA revealed no population structure within S. thompsoni, suggesting the survival of a single population in southern refugia during the glacial period. The ms loci results, in contrast, showed two genetically distinct clusters within S. thompsoni: One was predominant throughout Korean coasts (from the Yellow Sea, via the Korea Strait to the East Sea); the other was predominant at Dokdo Island in the East Sea; and both occurred in similar ratios at Wangdolcho Reef in the East Sea. A possible factor that restricts gene flow between Korean coastal and offshore populations in the East Sea may be related to the complex oceanic current patterns such as eddies and upwelling, which represent impermeable barriers to population connectivity for this species. Our findings highlight that these two populations might be representative of two separate stock within Korean waters and maintain their geographically related genetic structure.     

Comparison of morphological and genetic analyses reveals cryptic divergence and morphological plasticity in Stylophora (Cnidaria, Scleractinia)

A combined morphological and genetic study of the coral genus Stylophora investigated species boundaries in the Gulf of Aden, Yemen. Two mitochondrial regions, including the hypervariable IGS9 spacer and the control region, and a fragment of rDNA were used for phylogenetic analysis. Results were compared by multivariate analysis on the basis of branch morphology and corallite morphometry. Two species were clearly discriminated by both approaches. The first species was characterised by small corallites and a low morphological variability and was ascribed to a new geographical record of Stylophora madagascarensis on the basis of its phylogenetic distinction and its morphological similarity to the type material. The second species was characterised by larger corallite size and greater morphological variability and was ascribed to Stylophora pistillata. The analysis was extended to the intrageneric level for other S. pistillata populations from the Red Sea and the Pacific Ocean. Strong internal divergence was evident in the genus Stylophora. S. pistillata populations were split into two highly divergent Red Sea/Gulf of Aden and western Pacific lineages with significant morphological overlap, which suggests they represent two distinct cryptic species. The combined use of morphological and molecular approaches, so far proved to be a powerful tool for the re-delineation of species boundaries in corals, provided novel evidence of cryptic divergence in this group of marine metazoans.     

Morphology of the early zoeal stages of Macropipus tuberculatus (Roux, 1830) (Crustacea, Brachyura, Portunidae)

The first three zoeal stages of the portunid crab Macropipus tuberculatus (Roux, 1830) are described and illustrated from laboratory-reared material obtained from one ovigerous crab captured in the western Mediterranean Sea. Zoeae of M.tuberculatus can be distinguished from other known polybiinid species from the northeastern Atlantic and Mediterranean waters by a combination of meristic and morphometric features, especially by the number of setae in the outer lobe of the maxilla endopod. Larval morphology presents additional evidence supporting the split of the genus Macropipus into the genera Liocarcinus and Macropipus sensu stricto based on adult characters.      

The genetic variability of the red king crab, <Emphasis Type="Italic">Paralithodes camtschatica</Emphasis> (Tilesius, 1815) (Anomura,Lithodidae) introduced into the Barents Sea compared with samples from the Bering Sea and Kamchatka region using eleven microsatellite loci

The intentional introduction of red king crab, Paralithodes camtschatica (Tilesius, 1815) in the Barents Sea represent one of a few successful cases and one that now supports a commercial fishery. Introductions of alien species into new environments are often associated with genetic bottlenecks, which cause a reduction in the genetic variation, and this could be important for the spreading potential of the species in the Atlantic Ocean. Red king crab samples collected in the Varangerfjord located on the Barents Sea (northern Norway) were compared with reference crab samples collected from the Bering Sea and Kamchatka regions in the Pacific Ocean. All samples were screened for eleven microsatellite loci, based on the development of species-specific primers. The observed number of alleles per locus was similar, and no reduction in genetic variation, including gene diversity and allelic richness, was detected between the Varangerfjord sample and the reference sample from Okhotsk Sea near Kamchatka, indicating no genetic bottlenecking at least for the microsatellite loci investigated. The same results were found in comparison with the sample from Bering Sea. The level of genetic differentiation among the samples, measured as overall F _ST across all loci, was relatively low (0.0238) with a range of 0.0035–0.1000 for the various loci investigated. The largest pairwise F _ST values were found between the Bering Sea and Varangerfjord/Barents Sea samples, with a value of 0.0194 across all loci tested. The lowest value (0.0101) was found between the Varangerfjord and Kamchatka samples. Genetic differentiation based on exact tests on allele frequencies revealed highly significant differences between all pairwise comparisons. The high level of genetic variation found in the Varangerfjord/Barents Sea sample could be of significance with respect to further spreading of the species to other regions in the North Atlantic Ocean.     

Geographic variations of the mottled skate,Beringraja pulchra (Liu, 1932) (Rajidae) in the Yellow and East seas based on molecular and morphometric data

In order to prove the fisheries‐related hypothesis of the presence of two local populations of the mottled skate, Beringraja pulchra in the Yellow Sea (Sensu Jo et al., 2011 ), the geographic variations of 90 individuals (in molecule) and 129 individuals (in morphology) were investigated. The skates were collected from the middle Yellow Sea (Daechungdo), southern Yellow Sea (Heuksando), and the middle East Sea (Ulleungdo) using gill nets, bottom trawls and longlines. Comparing 471 base pairs of mitochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) sequences, only three haplotypes (BR1–BR3) were found. The Daechungdo and Heuksando individuals displayed all three haplotypes, whereas the Ulleungdo individuals displayed a single haplotype (BR3). Pairwise fixation indices (FST) showed that the Daechungdo and Heuksando individuals were not genetically distinguishable (with a value of ?0.0344), whereas the Ulleungdo individuals were clearly distinct from both the Daechungdo and Heuksando individuals (with values of 0.6875 and 0.6871, respectively). Similar to the molecular result, a canonical discriminant analysis based on seven morphometric characters showed that the Ulleungdo individuals had positive values on the first axis, whereas those from the other two locations had negative values, slightly differentiating the two populations (East Sea population vs Yellow Sea population). This study is the first to identify two populations of mottled skate in the northwest Pacific.     

Molecular identification of Pampus fishes (Perciformes, Stromateidae)

Concerning the nomenclature, most problems arise from the great confusion due to the morphological similarities in Pampus. Twenty-five individuals in Pampus were sampled from different localities about 2,000 km apart along the coast of China covering the Yellow Sea, the East China Sea and the South China Sea. The sequences of cytochrome c oxidase I (COI) and 16S rRNA (16S) genes of the mitogenomes were determined. Combined with the morphological characteristics, five Pampus species, P. minor, P. punctatissimus, P. chinensis, P. cinereus and Pampus sp., were identified. The genetic distance of intraspecies ranged from 0.000 to 0.004, while it varied from 0.012 to 0.133 for interspecies based on the 16S sequences. For COI sequence data analysis, the genetic distance of intraspecies ranged from 0.000 to 0.005, while it varied from 0.057 to 0.162 for interspecies. Phylogenetic trees showed that all Pampus fishes reciprocally constituted a monophyletic group with strong support. The sister-group relationships between P. minor and Pampus sp. and between P. chinensis and P. punctatissimus were revealed respectively. In the current GenBank data, P. minor is considered P. cinereus or P. argenteus by mistake. For the lack of a P. echinogaster specimen, we cannot decide on the name of Pampus sp. as P. argenteus or P. echinogaster.     

Nucleotide sequence variation of the mitochondrial COI gene in several eelpout species of the genus Zoarces (Zoarcidae, Pisces)

The mitochondrial COI gene was for the first time sequenced in eelpout species of the genus Zoarces from the Taui Bay of the Sea of Okhotsk: notched-fin Z. elongatus Kner, 1868 and the new sympatric form Zoarces sp., differing in a large set of morphological traits. The two species were compared with European eelpout Z. viviparus Linnaeus, 1758 from the Finnish Bay of the Baltic Sea. Divergence and phylogenetic analyses demonstrated a greater genetic similarity between Zoarces sp. and Z. viviparous than between sympatric Zoarces sp. and Z. elongatus.     

Taxonomic review ofapristurus platyrhynchus and related species from the pacific ocean (chondrichthyes, carcharhiniformes, scyliorhinidae)

Apristurus platyrhynchus and four related species were reviewed taxonomically.A. sibogae from Indonesia andA. micropterygeus from the South China Sea were valid species.A. verweyi from the Philippines andA. acanutus from the South China Sea were junior synonyms ofA. platyrhynchus. A. platyrhynchus was re-described, and its new biological information was provided.     

Trophodynamics of Protomyctophum (Myctophidae) in the Scotia Sea (Southern Ocean)

This study investigated spatial and temporal patterns in distribution, population structure and diet of Bolin's lanternfish Protomyctophum bolini, Tenison's lanternfish Protomyctophum tenisoni and gaptooth lanternfish Protomyctophum choriodon in the Scotia Sea using data collected by midwater trawl during spring, summer and autumn. Protomyctophum bolini was the most abundant species of the genus encountered throughout the Scotia Sea with the greatest concentrations occurring around the Antarctic Polar Front (APF). This species had a life cycle of 2+ years, but spatial differences in population structure were apparent as the I‐group was absent from all regions south of the APF, suggesting that the species does not recruit in the Scotia Sea. Protomyctophum tenisoni occurred mostly in waters characteristic of the APF and was absent from the southern Scotia Sea. It had a limited size range, but there was clear size‐related sexual dimorphism with males significantly larger than females. The species had a life cycle of c. 2 years, but the I‐group (c. 1 year old, 1 November to 31 October the next year) occurred only in regions close to the APF suggesting that recruitment is restricted to these waters. A seasonal southward migration for P. choriodon is likely as the species occurred mostly to the south‐west of South Georgia in summer, but extended to the sea‐ice sectors in autumn. Protomyctophum choriodon had a life cycle of 4+ years in the Scotia Sea and the population was dominated by age classes >3 years old. Larval stages were absent during the surveys for all species. Diurnal variations in vertical distribution were apparent for all three species. Interspecific variations in diet were evident, but all species were primarily copepod feeders, with Metridia spp., Rhincalanus gigas and Calanus simillimus generally dominating their diet. Small euphausiids, principally Thysanoessa spp., were also an important component of their diets, particularly for P. choriodon which had the largest body size. The spatial and temporal variations in diet for both P. bolini and P. tenisoni were broadly consistent with underlying abundance patterns within the mesozooplankton community.     

Microbial Diversity at a Hot,Shallow-Sea Hydrothermal Vent in the Southern Tyrrhenian Sea (Italy)

Microbial community thriving at shallow hydrothermal vent named Black Point, close to the Island of Panarea in the Southern Tyrrhenian Sea (Italy), was studied by microscopic, cultural and molecular methods. New strains of Bacillus and Geobacillus were isolated. Members of sulphur-oxidizing bacteria, belonging to the genera Halothiobacillus and Thiomicrospira were demonstrated by both culture-dependent and -independent methods. Genetic diversity of Bacteria was higher than that of Archaea. Bacterial 16S rRNA gene sequences from Black Point showed low levels of similarity with other yet deposited sequences, suggesting that new bacterial phylotypes are present in this site. Dominant populations of Bacteria belonged to uncultured members of Proteobacteria (mainly of the class Gammaproteobacteria), Firmicutes and Acidobacteriaceae. Primary production appeared to be supported by chemosynthetic and photosynthetic bacteria affiliated with members of Gammaproteobacteria. Most of the archaeal sequences matched those of yet-uncultivated Archaea, thus their role at this vent is not well understood.     

On Pentacoelum hispaniensis,a marine triclad from Spanish freshwater (Platyhelminthes,Tricladida, Maricola)

The marine triclad Pentacoelum hispaniensis is known from a freshwater biotope near Valencia, Spain. Preliminary results suggest a diploid complement of 12 chromosomes for the species. A historical scenario is presented for the occurrence of P. fucoideum in the Caspian Sea and the Baltic Sea, and for the presence of P. hispaniensis in the Mediterranean.     

A new species of Pomatoschistus (Teleostei,Gobiidae): the Mediterranean's smallest marine fish

The new sand goby species Pomatoschistus nanus (Teleostei: Gobiidae) is described from the northern coast of the Levantine Sea (eastern Mediterranean Sea) based on both morphological and DNA barcoding data. The new species is the smallest fish in the Mediterranean Sea and may be distinguished from congeners by the following features: predorsal area, first dorsal‐fin base and breast naked; δ‐pore missing; anterior point of the suborbital row b not reaching level of posterior point of suborbital row d; slightly emarginated caudal fin and nape coloration pattern. DNA barcode data clearly discriminate Pomatoschistus spp. in the neighbour‐joining tree with an average of 17·7% interspecific K2P distance. The most closely related taxon to P. nanus sp. nov. is Pomatoschistus bathi and the most distantly related is Pomatoschistus tortonesei with 11·9 and 21·9% K2P distances respectively. Morphometric and genetic data are also provided for Pomatoschistus bathi.     

Variability of DNA microsatellite loci in populations of Pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> Tilesius (Gadidae)

Despite almost a hundred years of studies on the Pacific cod’s biological and ecological peculiarities, many of them and especially population structure remain poorly understood. The variability of DNA microsatellite loci Gmo3, Gmo34, Gmo35, Pgmo32, and Gmo 19 was analyzed for the cod sampled in different areas of the North Pacific. The cod sampled nearby the Southern Kurils, differed significantly by Gmo3 and Pgmo32 compared to the populations inhabiting the Bering Sea, the Sea of Okhotsk and the coastal waters off Canada. Further, Pacific cod of the three latter populations demonstrated high similarity (I = 0.996) in spite of considerable geographic remoteness of these areas from one another.     

Assemblages of sea stars (Echinodermata: Asteroidea) and brittle stars (Echinodermata: Ophiuroidea) in the Weddell Sea (Antarctica) and off Northeast Greenland (Arctic): a comparison of diversity and abundance

Composition and distribution of asteroid and ophiuroid assemblages were investigated by means of Agassiz trawl catches at 34 stations in 220- to 1,200-m depth in the Weddell Sea and at 17 stations in 90- and 830-m depth off Northeast Greenland. A total of 86 species (48 sea stars, 38 brittle stars) were identified in the Weddell Sea whereas off Northeast Greenland a total of 26 species (16 sea stars, 10 brittle stars) were recorded. In both study areas, brittle stars were numerically more important than sea stars, and abundances generally decreased with water depths. Multivariate analyses revealed a conspicuous depth zonation of sea and brittle stars off Greenland. Very high abundances of Ophiocten sericeum and Ophiura robusta characterized the assemblages on shallow shelf banks whereas in greater depths Ophiopleura borealis, Ophioscolex glacialis and Ophiacantha bidentata became dominant, albeit at significantly lower densities. Mass occurrences of brittle stars, such as those recorded on Greenlandic shelf banks, have not been discovered in the Weddell Sea, where distinct assemblages were discriminated in deep shelf trenches as well as on the eastern and southern shelf. Ophioplocus incipiens, Ophiurolepis martensi and Ophiurolepis brevirima were the most prominent species on the eastern shelf. Ophiacantha antarctica, Ophiurolepis gelida and Ophionotus victoriae on the southern shelf, and Ophiosparte gigas as well as the asteriod Hymenaster sp., in the shelf trenches. Overall, the Weddell Sea housed conspicuously more asterozoan species than the waters off Greenland. Higher species diversity was also evident at both a regional and local scale, especially for the eastern Weddell Sea shelf. However, because many species from the Weddell Sea are closely related, the Weddell Sea assemblages were not significantly different from the Greenland ones in terms of taxonomic diversity and distinctness. Received: 29 April 1996/Accepted: 10 June 1996     

Morphology and ecology of the bloom-forming diatom <Emphasis Type="Italic">Chaetoceros contortus</Emphasis> from Peter the Great Bay,Sea of Japan

The morphology of the marine planktonic diatom Chaetoceros contortus Schütt from the Sea of Japan is described using light and electron microscopy. Because of morphological similarity, C. contortus was previously synonymized with the close species C. compressus Lauder by Gran and Yendo [22]. Abundant development of C. contortus was observed in 1997 in Amursky Bay (Sea of Japan). This species reached a maximum density of up to 1.3 × 10⁶ cells/liter near the water surface in mid May 1997 in the period of water-column stratification.