China Sea Off Research Articles

Kudoa tanakai n. sp. (Myxozoa: Myxosporea: Multivalvulida), a new kudoid species with spheroid myxospores from the scalpel sawtail (Actinopterygii: Prionurus scalparum) from western Japan.

We describe a new kudoid species, Kudoa tanakai n. sp., in the scalpel sawfish, Prionurus scalprum (Actinopterygii: Acanthuriformes: Acanthuridae), from the natural water around western Japan. The plasmodia were filamentous, localized in pseudocysts in the myofibers of the trunk muscles. The occurrence of plasmodia in the trunk muscle showed no site preference. Its myxospores were spheroid, measuring 6.6-7.6 (7.0) µm by 5.8-6.9 (6.3) µm in apical view (width) and 5.7-6.6 (6.2) in length (n = 30), with four shell valves and a corresponding number of spheroid polar capsules. Shell valves lacked apical protrusions, but scanning electron microscopy revealed that one of the four shell valves had two semi-lunar flaps at its apical terminus. Nucleotide sequencing of the small and large subunit ribosomal RNA genes of the present isolate showed phylogenetic affinities to kudoid species characterized by spheroid myxospores, such as K. musculoliquefaciens, K. hemiscylli, and K. carcharhini, but was molecularly and morphometrically distinct from these and other kudoid species. For direct comparison, Kudoa hemiscylli was collected from the Pacific spadenose shark, Scoliodon macrorhynchos (Elasmobranchii: Carcharhiniformes: Carcharhinidae), in the South China Sea off Guangdong Province, China, and the myxospore surface of the species was observed using scanning electron microscopy. Our study describes the new host and distribution record of this kudoid species originally described from a variety of elasmobranchs in the Australian Coral Sea.

Gigantic Anemone Species in the Deep ‘Churaumi’—Description of a New Species of the Genus <i>Telmatactis</i> (Cnidaria: Anthozoa: Actiniaria: Metridioidea), <i>Telmatactis profundigigantica</i> sp. nov.

Although the members of the genus Telmatactis Gravier, 1916 have been reported from broad area of the world including Japanese waters, the localities of the species have been limited to shallow areas. In this study, we report a new species in this genus, Telmatactis profundigigantica sp. nov., collected from the deeper area than 200 m of the East China Sea off Okinawa Island, discovered by ROV, and taken care of in Okinawa Churaumi Aquarium. This new species is chiefly characterized by its comparatively huge size of its body, over 10 cm in diameter and height, far larger than the other known species of this genus. Moreover, this species has characteristic multiple-headed tentacles and large cnidae in its acrospheres. In the present article, we also discuss the severe toxicity of this species and touch on the ecology of deep-sea anemones.

A new species of the deep-sea shrimp genus Glyphocrangon A. Milne-Edwards, 1880 (Decapoda: Caridea: Glyphocrangonidae) from the South China Sea off Pratas Island.

A new species of the deep-sea caridean genus Glyphocrangon A. Milne-Edwards, 1880, G. obtusis n.sp., is described and illustrated on the basis of the material collected in the South China Sea off the Pratas Island. It appears close to G. hakuhoae Takeda Hanamura, 1994 and G. robusta Komai, 2004 among the 93 described species in Glyphocrangon. From G. hakuhoae, the new species is distinguished by the rostrum with less developed convexity on the dorsolateral margin and lacking transverse septa, and the less elevated median carinae on the pleomeres 15. From G. robusta, the new species differs in lacking transverse septa at the rostrum, the fourth carina on the carapace with the two anterior parts unaligned and the posterior part divided into four lobes. Molecular genetic analysis using the barcoding segment of the mitochondrial COI gene supports the establishment of the new species.

Three new species of Apseudomorpha (Crustacea, Tanaidacea) from Jiaozhou Bay, the Yellow Sea, and the South China Sea off coasts of China.

Three new species of the crustacean order Tanaidacea are described from the coasts of China. Apseudesspinidigitussp. nov. (family Apseudidae), from the South China Sea, can be distinguished from the most similar species, A.nhatrangensis, by the features of the maxilliped endite, cheliped dactylus, pereopod 1 carpus and propodus, and pleopods basal article. Phoxokalliapseudesshandongensissp. nov. (family Kalliapseudidae), from Jiaozhou Bay and the Yellow Sea, can be differentiated from the most similar species, P.gibbus, by the features of the antennule article 1, pereopods 1 and 6 propodi, and uropod basal article. Swireapseudesplanafrontissp. nov. (family Parapseudidae), from Jiaozhou Bay, can be clearly separated from its congeners by its rostrum, antennule article 1, and pereopod 4 dactylus. A morphological key and comparison table of genus Apseudes from the South China Sea, as well as all known species of the genera Phoxokalliapseudes and Swireapseudes are provided.

First records of the seamoth, Pegasus nanhaiensis (Actinopterygii: Syngnathiformes: Pegasidae), from the southern South China Sea, with notes on fresh coloration

Three seamoth specimens (45.5–56.9 mm standard length; SL) (Syngnathiformes: Pegasidae), originally identified as Pegasus laternarius Cuvier, 1829, but now recognized as representing P. nanhaiensis Zhang, Wang et Lin, 2020, a species recently described from the northern South China Sea off Yangjiang and Beihai, China, were obtained at a local fish market in Maha Chai, Samut Sakhon Province, Thailand on 6 July 2012, having been caught in the northern Gulf of Thailand. In addition, single specimens, reported as P. laternarius or Spinipegasus laternarius from Bidong Island, South China Sea off the Malay Peninsula (46.1 mm SL) and from Ko Kradat, Trat Province, eastern Gulf of Thailand (66.1 mm SL), were re-identified here as P. nanhaiensis. Thai specimens and Malaysian record represent the first records of P. nanhaiensis from Thailand and Malaysia, respectively, and from outside Chinese coastal waters. Additionally, the Bidong specimen is the southernmost record for the species. The fresh coloration of P. nanhaiensis is described for the first time.

Atmospheric Iron and Aluminium Deposition and Sea-Surface Dissolved Iron and Aluminium Concentrations in the South China Sea off Malaysia Borneo (Sarawak Waters)

South China Sea (SCS) is an oligotrophic sea which usually receives low nutrients supply. However, massive atmospheric dust input was occurred during the haze event in Southeast Asia for almost every year. The input of dissolved iron (DFe) and dissolved aluminium (DAl) from dust and nearby land into SCS off Sarawak Borneo region during the worst haze event in 2015 of the Southeast Asia were investigated. The estimation dust deposition during this study was 0.162 mg/m2/yr. The atmospheric fluxes of total Fe and total Al at the offshore Sarawak waters were 0.611 µmol/m2/yr and 2.03 µmol/m2/yr, respectively, where the readily available dissolved Fe and Al from the dust were 0.11 µmol/m2/yr (DFe) and 0.31 µmol/m2/yr (DAl). Fe has higher solubility (17.78%) than Al (15.21%). The lateral fluxes (e.g. from the nearby land) were 37.08 nmol/m2/yr (DFe) and 125 nmol/m2/yr (DAl), with strong Fe organic ligand class L1 (log K:22.43 – 24.33). High concentrations of DFe and DAl at the surface water of the offshore region, coincided with high concentration of macronutrients due to the prevailing south-westerly winds originated from the west Kalimantan. Low residence times, ~0.92 (DFe) and ~1.31 (DAl) years, corresponded well with DAlexcess in surface seawater due to biological utilization of DFe. Future works emphasize on natural organic Fe(III) ligands and phytoplankton study are needed for better understanding on biogeochemistry of Fe and Al at SCS off Malaysia Borneo.

New species of Microspio Mesnil, 1896 (Annelida: Spionidae), with additions to the description of M. pigmentata (Reish, 1959) and comparative notes on all members of the genus

Three new species of Microspio were found in collections from a range of depths including shallow water in Bermuda, the continental shelf off Massachusetts, and deep water in the South China Sea off Brunei. Microspio fischeri, new species, is associated with shallow water sponges in Bermuda where it is a prey species of a predatory syllid; it is characterized by the medial placement of the first pair of branchiae as well as unusual notopodial capillaries in anterior chaetigers and enlarged notopodial lobes in posterior chaetigers. Microspio lydonia, new species, from the continental shelf on the east coast of the United States is distinguished from M. pigmentata (Reish, 1959) from the west coast by differences in the structure of the nuchal organs and hooded hooks, pigmentation, and Methyl Green staining patterns. Additions to the description of M. pigmentata include illustration of the nuchal organs and dorsal ciliary bands. Microspio ariena, new species, from deep water in the South China Sea off Brunei has enlarged branchiae with large glands that stain deeply with Methyl Green on a few anterior chaetigers, followed by much smaller branchiae on additional chaetigers. The three new species bring the total of described species in the genus to twenty-one, although some species remain problematic. A table comparing important characteristics of all 21 known species of Microspio is included.

Sources of Polycyclic Aromatic Hydrocarbons in South China Sea Short Core Sediments Off Southern Part Terengganu, Malaysia and Multivariate Statistics Approaches

Sediment cores from the southern South China Sea off the Terengganu coast were analyzed for polycyclic aromatic hydrocarbons (PAH s) and perylene. The concentrations of total 17 PAH (TPAHs) and perylene varied between 5.45-27.7 ng/g and 0.51-7.77 ng/g, respectively. Analyses of variance showed significant differences between the stations, but not in sub-bottom depths at the 0.05 level. The PAH cross plots showed a predominance of pyrogenic over petrogenic PAH s. Principal component analysis (PCA) showed clustered PAH s that are correlated with total organic carbon (TOC), indicating the importance of surface runoff via fluvial transport for contributing these PAH s to the coastal environment of the study area. Overall, the concentrations of PAH s in the study area are considered to be in the low range, not exceeding the 100 ng/g mark.

A new species of Lepidotrigla from the South China Sea off Vietnam(Teleostei: Scorpaeniformes: Triglidae).

A new species of the gurnard genus Lepidotrigla is described from the South China Sea off southernmost central Vietnam. Lepidotrigra firmisquamis sp. nov. is most similar to L. alata and L. marisinensis and co-occurs with L. marisinensis in the Bays of Nha Trang and Van Phong, but can be easily distinguished from both species by the well developed preocular spines and postorbital groove and by a slightly lower lateral-line scale count (54-58 instead of 58-64). A comparison with all Lepidotrigla species known from the South China Sea is presented.

Note on rare snake eels (Anguilliformes: Ophichthidae) and additional data on three Neenchelys recently described from Taiwan.

Three rare snake eel species, Allips concolor McCosker, 1972, Neenchelys daedalus McCosker, 1982, and Apterichtus moseri (Jordan Snyder, 1901), were newly collected from Taiwan. The distribution ranges of the first two species are now extended to the South China Sea off southern Taiwan and that of the third is extended southward to off northwestern Taiwan. Supplemental data for three recently described species, Neenchelys diaphora, N. gracilis and N. similis, from Taiwan are provided.

<i>Anilocra prionuri</i> (Isopoda: Cymothoidae), a marine fish ectoparasite, from the northern Ryukyu Islands, southern Japan, with a note on a skin wound of infected fish

Anilocra prionuri Williams & Bunkley-Williams, 1986, is reported based on a female specimen collected from the skin below the nostril of a scalpel sawtail, Prionurus scalprum Valenciennes, 1835, in the southern East China Sea off Kuchinoerabu-jima Island, one of the northern Ryukyu Islands, southern Japan. Anilocra prionuri was previously reported only from off the Pacific coast of central Hon­shu, Japan, but the present collection extends the geographical distribution range of the species from central Honshu southwest to the northern Ryukyu Islands and represents its first record from the East China Sea. The fish had a wound with heavily damaged epidermis at the attachment site of A. prionuri. It was a rare parasite of P. scalprum at the collection site.

A new species of the genus Pectinodonta Dall, 1882 (Gastropoda: Pectinodontidae) from the East China Sea

ABSTRACTA new pectinodontid species collected from sunken wood in the East China Sea off Zhejiang Province, China, is described and assigned to the genus Pectinodonta Dall, 1882. This new species, Pectinodonta mazuae n. sp., has a medium sized shell with a fine sculpture; shell width about 72%–75% of shell length, height about 61%–66% of length, and each lateral tooth has 16 or 17 cusps. These features may be used to distinguish the new species from its congeners.http://zoobank.org/urn:lsid:zoobank.org:act:4B3D491F-868D-4F9A-8CC9-005829BF691E

Biomarker assessments of sources and environmental implications of organic matter in sediments from potential cold seep areas of the northeastern South China Sea

Multi-biomarker indexes were analyzed for two piston cores from potential cold seep areas of the South China Sea off southwestern Taiwan. Total organic carbon (TOC) normalized terrestrial (n-alkanes) and marine (brassicasterol, dinosterol, alkenones and iso-GDGTs) biomarker contents and ratios (TMBR, 1/P mar-aq, BIT) were used to evaluate the contributions of terrestrial and marine organic matter (TOM and MOM respectively) to the sedimentary organic matter, indicating that MOM dominated the organic sources in Core MD052911 and the sedimentary organic matter in Core ORI-860-22 was mainly derived from terrestrial inputs, and different morphologies were the likely reason for TOM percentage differences. BIT results suggested that river-transported terrestrial soil organic matter was not a major source of TOM of sedimentary organic matter around these settings. Diagnostic biomarkers for methane-oxidizing archaea (MOA) were only detected in one sample at 172 cm depth of Core ORI-860-22, with abnormally high iso-GDGTs content and Methane Index (MI) value (0.94). These results indicated high anaerobic oxidation of methane (AOM) activities at or around 172 cm in Core ORI-860-22. However in Core MD052911, MOA biomarkers were not detected and MI values were lower (0.19–0.38), indicated insignificant contributions of iso-GDGTs from methanotrophic archaea and the absence of significant AOM activities. Biomarker results thus indicated that the discontinuous upward methane seepage and insufficient methane flux could not induce high AOM activities in our sampling sites. In addition, the different patterns of TEX86 and Uk′ 37 temperature in two cores suggested that AOM activities affected TEX86 temperature estimates with lower values in Core ORI-860-22, but not significantly on TEX86 temperature estimates in Core MD052911.

Biology of Incidental Catch Sea Star Stellaster childreni Gray, 1840 (Echinodermata: Asteroidea), from Malaysian Borneo Exclusive Economic Zone.

Sea star (class Asteroidea, phylum Echinodermata) is one of the most successful marine organisms inhabiting a wide range of habitats. As one of the key stone species, sea stars are responsible for maintaining much of the local diversity of species within certain communities. Malaysian Exclusive Economic Zone (EEZ) Resource Survey had been carried out from 16th Aug to 6th Nov 2015 and one of the invertebrate by-catch organisms is sea star Stellaster childreni Gray, 1840. This study documents morphological characters and diet of the sea star, besides providing brief descriptions of the habitats based on particle size analysis and vessel log data sheet. A total of 217 individuals had been examined throughout this study. Fragments of flora and fauna were found in the gut including Mollusca (gastropod, bivalves, and scaphopods), sponge seagrass, and seaweed as well as benthic Foraminifera. Stellaster childreni were found at depth of 45 m to 185 m in the South China Sea off Sarawak Malaysia, with various sea bottom substrata. Approximately 41% of S. childreni were found at a mixture of sandy and muddy substratum, followed by mixture of sandy and coral (19.3%), muddy substratum (17.5%), coral substratum (11.5%), and sandy areas (10.6%). The widely distributed sea star on different types of sea beds suggested healthy deep sea ecosystem; thus Malaysia should explore further potential fisheries resources in the EEZ off Sarawak coast.

English

Three short sediment cores (12-32 cm) from South China Sea off Southern Terengganu were collected during May (post-Northeast monsoon) and September (pre-Northeast monsoon) 2007. The concentration of total organic carbon (TOC) obtained ranged from 0.41-2.23 and 0.38-2.31% during post and pre-monsoon, respectively. TOC concentration was found to decrease with depth and distance from the coast and river mouth. In particular, station with close proximity to the coast exhibits most pronounced variation of TOC with depth. Besides spatial variation, it is noted that the seasonal variations also considerably affect the distribution and concentrations of TOC, where both near and offshore sampling stations showed significant variations in TOC content during May and September sampling. These findings suggest the importance of terrestrial organic carbon flux, physical mixing and seasonal variations in regulating the concentration and distribution of the organic carbon in the study area.

Sedimentation in remnant ocean basin off SW Taiwan with implication for closing northeastern South China Sea

Taiwan is one of the most cited examples of modern mountain building in an oblique arc–continent collision. However, the recognition and significance of the Taiwan remnant ocean basin in the final stages of the collision of Luzon with the Chinese margin have long been ignored. This paper emphasizes the Taiwan remnant ocean basin as the main sink for sediments from the uplifted Taiwan suture zone and as a record of clues to the suturing history of the Taiwan collision zone. A part of the palaeo South China Sea has been closed by oblique collision of the Luzon Arc with the Chinese margin in the Taiwan region since about 4 Ma. As collision continued southward along the Taiwan–Luzon convergent zone the remaining South China Sea off SW Taiwan became the Taiwan remnant ocean basin. Beginning about 1.6 Ma much sediment from the longitudinal drainage of the Taiwan orogen was fed into this remaining basin and trapped in the intra-slope basins of the Kaoping slope, with some sediment bypassing via the Kaoping Canyon to the lower reach of the Penghu Canyon. This basin is characteristic of an axial canyon–deep-sea channel–oceanic trench system without significant sediment accumulation in submarine fans. Excess sediments from the Penghu Canyon mainly spill over out of the closing basin to the South China Sea and Manila Trench via the deep-sea Penghu Channel. The Taiwan–Luzon convergent zone continues along the NE South China Sea where the Taiwan remnant ocean basin exists. The implication of the convergence is that the Taiwan remnant ocean basin will keep shrinking in the next few million years southward to the northern end of the Manila Trench at around 20°N, where collision is replaced by subduction. The remnant ocean basin would be closed and deformed, and sediments would be accreted to uplifted collisional terranes north of the Manila Trench.

Distribution and sources of lipid compound series in sediment cores of the southern South China Sea.

Three short sediment cores from inner continental shelf of the southern South China Sea (5-50 km) off Terengganu were analyzed for lipid contents (i.e., homologous aliphatic compounds and sterols) using gas chromatography-mass spectrometry. The concentrations of the total aliphatic hydrocarbons (TAHs) ranged from 0.152 to 6.91 μg/g dry weight. The n-alkane distribution was from nC₁₃ to nC₃₆, with a carbon preference index (CPI₁₃₋₃₅) from 1.08 to 4.28 and a carbon number maximum (Cmax), depending on a sample, at 31 or 18. In addition, a strong odd-to-even carbon number predominance was observed in nC₂₅-nC₃₅ range. The distribution of the n-alkanoic acids and n-alkanols in all samples exhibited an even-to-odd carbon number predominance and ranged from C₁₀ to C₂₆ and from C₁₂ to C₃₄, respectively. The n-alkanols were dominated by the long-chain homologs with Cmax at 22; on the other hand, the n-alkanoic acid distributions showed a predominance of short-chain homologs with a Cmax at 16. The total sterol concentrations ranged from 0.41 to 3.57 μg/g dry weight. Cholesterol was most abundant at the offshore stations, whereas sitosterol was dominant at near-shore station. Pentacyclic triterpenoids such as friedelin and taraxerol α- and β-amyrins, which are known biomarkers for higher plants, were detected at all stations with a dilution trend offshore. In conclusion, the marine sediments off southern Terengganu can still be considered uncontaminated, where the compound sources are biogenic from terrestrial plants superimposed with a marine productivity input.

Neoepinnula minetomai, a new species of sackfish from off Kuchierabu-jima Island, southern Japan (Actinopterygii: Gempylidae)

Neoepinnula minetomai, a new species of sackfish, is described from two specimens collected from the East China Sea off Kuchierabu-jima Island, Kagoshima, Japan, at depths of about 380–420 m. The species is separable from its two congeners, Neoepinnula americana and Neoepinnula orientalis, by the following combination of characters: orbit huge, 1.0–1.1 in snout length, its upper margin forming predorsal profile in lateral view; fleshy interorbital width less than orbit diameter; posteroventral corner of preopercle forming an acute angle; distal margin of second dorsal and anal fins concave; tip of lower jaw without distinctly enlarged fangs; lower lateral line above pectoral fin base hidden behind opercle; oral cavities uniformly blackish; head length (HL) 33.5–34.8 % standard length (SL); body depth at pelvic fin base 28.2–29.0 % SL, and at anal fin origin 27.0–28.0 % SL; pectoral fin length 17.9–18.1 % SL; upper caudal fin lobe length 25.6 % SL; lower caudal fin lobe length 23.4–24.0 % SL; snout length 31.3–33.4 % HL; postorbital length 38.2–39.0 % HL; upper jaw length 40.5–41.2 % HL.

Episodic events imposed on the seasonal nutrient dynamics of an upwelling system off northeastern Taiwan

An upwelling center has been frequently observed on the shelf break of the East China Sea (ECS) off northeastern Taiwan, where the Kuroshio encounters an abrupt shoaling topography. The region is also located under the track of Asian dust (AD) storms and frequently disturbed by typhoons. To examine the seasonal nutrient dynamics of the upwelling and the potential impacts of these episodic events, transect stations across the upwelling center were visited at intervals of 1–3months from November 2003 to January 2005. The results of the water temperature profiles indicated that the upwelling persisted throughout the year with the most intensified events occurring in winter. Seasonally, a higher nitrate concentration was observed during the stronger upwelling period. The highest nitrate value was however observed during an AD storm, with an average value of 8.3μM for the top 30m. Interestingly, the N/P ratio was larger than 16 during these episodic events, and the N/P ratios were equal to or smaller than 16 during other periods. On average, the estimated values from wet deposition constituted 17.3% of the total estimated nitrogen input. This suggests that atmospheric deposition, particularly during the episodic events, might be an important external nutrient source.

On the tidally driven circulation in the South China Sea: modeling and analysis

The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. An unstructured-grid SUNTANS model is employed to perform depth-averaged simulations of the circulation in the South China Sea. The model is tidally forced at the open ocean boundaries using the eight main tidal constituents as derived from the OSU Tidal Prediction Software. The model simulations are performed for the year 2005 using a time step of 60 s. The model reproduces the spring-neap and diurnal and semidiurnal variability in the observed data. Skill assessment of the model is performed by comparing model-predicted surface elevations with observations. For stations located in the central region of the South China Sea, the root mean squared errors (RMSE) are less than 10 % and the Pearson’s correlation coefficient (r) is as high as 0.9. The simulations show that the quality of the model prediction is dependent on the horizontal grid resolution, coastline accuracy, and boundary locations. The maximum RMSE errors and minimum correlation coefficients occur at Kaohsiung (located in northern South China Sea off Taiwan coast) and Tioman (located in southern South China Sea off Malaysia coast). This may be explained with spectral analysis of sea level residuals and winds, which reveal dynamics at Kaohsiung and Tioman are strongly influenced by the seasonal monsoon winds. Our model demonstrates the importance of tidally driven circulation in the central region of the South China Sea.