Length–weight relationships of three fish species from the South China Sea

The length–weight relationships were determined for three fish species: Histiopterus typus (Temminck & Schlegel, 1844), Branchiostegus argentatus (Cuvier, 1830), and Ilisha elongata (Anonymous [Bennett], 1830). Samples were collected from the South China Sea with commercial trawls in June 2016 using trawl nets. Prior to this study the length–weight relationships for these three species were unknown.     

Length–weight relationships of four marine fish species caught in the South China Sea

Length–weight relationships are described for four marine teleost fish species caught in the South China Sea. A total of 625 individuals were collected from April to August 2007 and November 2012 using a bottom trawl (mesh size, 3.9 cm) and longline fishing. The values of parameters a and b ranged from 0.004612 to 0.02137 and 3.019 to 3.371, respectively. The high r² values (all >.950) indicate that these relationships are robust and will be appropriate for use in fisheries management of these species.     

Universalizing the Law of the Sea in the South China Sea Dispute

This article argues that a resolution of the maritime disputes in the South China Sea must be based upon a universalist framework where the maritime interests of the world are upheld. The article discusses the universalist framework of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the universalist approach taken by the Tribunal on 12 July 2016 in the South China Sea Arbitration regarding the extinguishment of a state's “exceptionalist” maritime claims and the adoption of strict criteria for the characterization of features at sea.     

Biodegradation of polyhydroxyalkanoates (PHAs) in the South China Sea and identification of PHA-degrading bacteria

The biodegradation patterns of two types of PHA, a 3-hydroxybutyrate (3-PHB) polymer and a 3-hydroxybutyrate and 3-hydroxyvalerate (3-PHB/3-PHV) copolymer, were studied in tropical marine environments (Dam Bay, South China Sea, Nha Trang, Vietnam). No reliable differences in the degradation of 3-PHB and 3-PHB/3-PHV were revealed. It was shown that the degradation process depended mainly on the shape of a polymer product and its production method: the degradation of polymer films was found to be more active than that of molded solids. A decrease in the molecular mass of both types of PHA was detected in the course of the degradation of PHA samples. However, the degree of PHA crystallinity did not change; that is, the levels of degradation of both the amorphous and crystalline phases of PHA were almost the same. Among microbial PHA degraders, three bacterial strains, Bacillus sp. IBP-V002, Enterobacter cloacae sp. IBP-V001, and Gracilibacillus sp. IBP-V003, were identified based on the results of morphological, biochemical, and molecular phylogenetic analyses. The ability of the representatives of the genera Gracilibacillus and Enterobacter to degrade PHA was revealed for the first time.     

Length‐weight relationships of 69 fish species in the Beibu Gulf,northern South China Sea

Sixty‐nine fish species belonging to 41 genera from 29 families and seven orders were collected during 2006–2007 by otter trawl in Beibu Gulf, northern South China Sea, for analysis of their length‐weight relationships (WLRs). The analysis included 19 species for which no previous WLR estimates were available in FISHBASE.     

南海生物多样性的保护

海洋对我们有很大的魅力,仅就生物多样性而言,我国是联合国《生物多样性公约》的最早缔约和制定保护生物多样性行动计划的国家之一,保护生物多样性是我国人民必须履行的共同义务,也是关系子孙后代生存的大事.1地理位置南海位于我国东南,面积约350 km2,平均深度为1,212 m,最大深度为5,377 m.它是一个长轴东北-西南向的边缘海,由西沙、中沙、东沙和南沙群岛构成,四大岛礁群散布其中,西南还有北部湾和泰国湾两大海湾.南海东临菲律宾群岛,北靠华南大陆,南接加里曼丹和苏门答腊,西接马来半岛和中南半岛.南海周边共有9个海峡,与东海、太平洋、苏禄海、爪哇海和印度洋相连通,地理位置非常重要,是欧、亚、非通道,在安全航运、经贸往来、环境保护、资源开发和军事战略等方面都具有非常重要的地位.     

南海深海沉积物中52株真菌的初步分离鉴定及其代谢产物活性

【背景】深海环境复杂多样,蕴含着丰富的真菌资源,为深海真菌结构新颖代谢产物化学及生物活性研究提供了新契机。【目的】对南海深海环境来源真菌进行初步鉴定和代谢产物活性初步研究,旨在筛选和发现潜在的药源真菌新资源,为南海深海真菌资源的进一步开发利用奠定基础。【方法】基于内转录间隔区(ITS)序列测定对分离得到的52株真菌进行初步鉴定,利用纸片扩散法、Solis改良法和DPPH自由基清除法对真菌粗浸膏进行了抗菌(ABA)、卤虫致死(BSL)和抗氧化活性(ABTS)筛选。【结果】52株真菌分布在16个属,其中枝孢菌属(Cladosporium)、曲霉属(Aspergillus)为优势菌群,分别占菌株总数的25.00%、23.08%;32株真菌发酵产物具有抑制至少1种指示菌的活性,其中8株对所有指示菌均有抑制作用;23株具有一定强度的卤虫致死活性,占总数的44.23%,其中有2株活性较显著,IC50值为68.59μg/mL和78.83μg/mL;30株具有DPPH自由基清除活性,占总数的57.69%,其中有9株活性较显著,EC50值低于100μg/mL。【结论】初步认知了南海部分海域深海沉积环境真菌分布和代谢产物活性特征,发现了一批潜在的活性真菌资源,为后续深海真菌代谢产物化学多样性及其功能研究提供支撑。     

种间互作对雷州湾海域鱼类群落结构的影响

从鱼类种间互作及其生态网络特征视角研究鱼类群落结构特征,对解析多鱼种共存机制和基于群落水平的多鱼种资源管理均具有重要意义。为分析鱼类资源利用的竞争互作对群落结构稳定性的影响,根据2016-2018年8个航次的雷州湾海域底拖网调查的鱼类数据,将空间生态位重叠理论和生态网络建模相结合,从种间互作的角度应用加权聚类系数C、加权平均路径长度A、关联度Co等指标分析鱼类的群落结构。结果表明：①鱼类生态位重叠所形成的种间互作网络季节变动较大,而年度变动则相对较小,共包含鱼类58-122种,种间互作的关系数量1318-7103。②雷州湾海域鱼类群落内种间互作密集,聚合程度高（C介于0.84-0.98）且能量传递效率高（A介于0.02-0.09）,呈现互作弱化之趋势（Co介于0.32-0.48）,群落结构总体较稳定。③小尺度范围（20°40''-21°00''N,110°30''-110°45''E）内,鱼类群落内种间互作特征是维持多种鱼类共存的重要内因。该特征表现为季节和年度的变化总体上相似,种间直接关联程度与种间互作强度呈正相关（P<0.01）,而局部聚合程度与种间直接关联、互作强度均呈负相关（P<0.01）。本研究可为鱼类群落结构稳定性的量化评价和资源养护的管理规划提供参考依据。     

Length–weight relationships of four fish species from the Beibu Gulf,South China Sea

The length–weight relationships of four fish species: Lophiomus setigerus (Vahl, 1797), Uranoscopus oligolepis Bleeker, 1878, Cynoglossus oligolepis (Bleeker, 1855), and Cynoglossus arel (Bloch & Schneider, 1801) were determined. Specimens were collected from the Beibu Gulf in the South China Sea by using bottom trawl nets (mesh size 4.0 cm, at a towing speed about 3 knots) in the seasonal investigations from August 2010 to May 2011. The values of parameter b of these four species ranged from 2.982–3.489 and remained within the normal range of 2.5–3.5.     

东海和黄海主要鱼类的食物竞争

以2000年和2001年在东、黄海两次大面调查所收集的、占总生物量90%的重要生物种类中的鱼类为研究对象,通过分析胃含物获得各饵料成分的重量百分比,用Pianka(1973)提出的公式计算的饵料重叠系数分析了东、黄海主要鱼类之间的食物竞争状况,以了解食物竞争与种群变动和优势种交替之间的相互关系。结果表明:黄海主要鱼类的食物竞争对象主要为太平洋磷虾、脊腹褐虾和,东海主要鱼类的食物竞争对象主要为太平洋磷虾、细条天竺鱼、发光鲷、、七星底灯鱼和带鱼。东、黄海鱼类通过摄食种类、摄食食物大小、摄食时间和栖息地的分化来减少食物竞争,从而维持群落结构的动态平衡。渔业资源群落结构的变化将导致食物竞争状况发生改变;鱼类食物竞争状况也会影响种群动态,但要确定食物竞争程度还需进一步深入研究     

Molecular identification and phylogenetic analysis of fungal pathogens isolated from diseased fish in Xinjiang,China

The outbreaks of fungal diseases in cultured fish have been severe in recent years, which is harmful to the healthy and sustainable development of fish farming. In this study, an investigation was conducted for significant fungal infections of 12 species of fish in four regions in Xinjiang, China, to understand the distribution of local fish fungal pathogens. Twenty-six fungal strains with pathogenicity were isolated, and the challenge experiment showed that eight strains from Changji area had high infection rate to fish eggs. Based on internal transcribed spacer sequence data and molecular analysis, the 26 strains were classified into nine different species of six fungal genera. Phylogenetic analysis showed that all strains were divided into two clades, namely Cluster 1 (contains only the genus Mucor) and Cluster 2 (consists of five small branches), and the distribution of strains from the same region was scattered in two clusters. There is no strict host selectivity for these fungi to infect fish. Mucor sp. are the main fungal pathogen of fish in these four regions, whereas Hypophthalmichthys molitrix and Carassius auratus are two types of fish that were susceptible to pathogen. In addition, the environmental adaptability experiments showed that eight highly pathogenic strains have different adaptability to the environment, and their optimum temperature and pH were 25°C and 7.0, respectively, whereas the concentration of NaCl was negatively correlated with the growth of strains. Therefore, these results indicated that the coinfection of multiple fungal pathogens in a culture region should be considered in the future study.     

China's U-Shaped Line in the South China Sea Revisited

Despite its existence on the Chinese maps for more than six decades, the U-shaped line, as a traditional maritime boundary line of China in the South China Sea, has never received a wide recognition in the world community, much less by the other claimant states in the South China Sea. The U-shaped line is a legal conundrum not only for China but also for the world community, particularly after the map with the U-shaped line, together with China's Notes Verbale with respect to the claims to the outer continental shelves made by Malaysia and Vietnam, were submitted to the UN Commission on the Limits of Continental Shelf in May 2009. This article discusses China's recent practice relating to the U-shaped line as well as the external factors that affect the validity of the line and tries to unravel the legal puzzle posed by the line.     

Length‐weight relationships of three fish species from the costal of Hainan,the South China Sea

Length‐weight relationships were determined for three fish species [Bregmaceros rarisquamosus Munro, 1950; Sardinella albella (Valenciennes, 1847) and Cynoglossus macrolepidotus (Bleeker, 1851)] inhabiting the coastal of Hainan, China. Fishes were collected using gillnets (mesh size 0.5 cm) and electrofishing from 2005 to December 2012. The b‐values of the equations ranged between 2.57 for Bregmaceros rarisquamosus and 3.34 for Cynoglossus macrolepidotus and thus were just inside the acceptable range for this value. Further, for B. rarisquamosus a new TLmax was recorded.     

南中国海地区湿地植物多样性研究

对南中国海地区湿地的植物多样性进行了深入研究,调查范围包括浅水海域、潮间带滩涂、河口地带和三角洲冲积平原、三角洲基塘等湿地类型。基本弄清了南中国海湿地植物的生境多样性、物种多样性以及生态系统多样性,为有效保护和合理利用南中国海湿地资源提供科学的依据。调查表明,南中国海近海近岸湿地生境多样性复杂,物种丰富。主要生境类型有浅海水域湿地等13类;湿地高等植物的生态系统主要有红树林湿地生态系统等6种;南中国海地区湿地共有高等植物179科,593属,829种。国家Ⅰ级保护植物3种,Ⅱ级保护植物9种。     

东海区底层及近底层鱼类资源的空间异质性

运用空间自相关指数和变异函数分析东海区底层及近底层鱼类资源的空间自相关性和空间变异．其空间分布平均场的Geary c和Moran Ⅰ指数分别为0．38和0．52,各向同性随机变异占总变异的59．9％。表明其空间分布具有中等自相关特性,空间变异中由随机引起的变异大于由空间相关尺度过程引起的变异;各方向变异属于几何异向性,资源密度的年际变化与C、C0和C+C0均呈正相关,说明年际平均密度的增加由空间自相关变异和随机变异共同引起,随机变异略强于空间自相关变异。     

南海台风引发藻华的生物机制

海洋浮游植物的生长和小型浮游动物的摄食,与温度、光照和营养盐等因素密切相关。中国南海海盆是层化结构稳定的寡营养海,然而每年台风过后都有大量藻华的报道。为了探究台风引发藻华的生物形成机制,通过南海海域表层和次表层叶绿素最大层(DCM)中的小型浮游动物的摄食活动以及浮游植物对光照和营养响应的现场实验,探究小型浮游动物摄食、光照和营养对海洋浮游植物生长和群落结构的调控作用。实验表明:1)表层水体中的小型浮游动物摄食速率明显大于DCM层;小型浮游动物摄食在表层水体中以大粒级的浮游植物(5μm)为主,在DCM层中没有明显粒级选择;自然光中的紫外线能增加小型浮游动物的摄食;营养盐添加轻微降低小型浮游动物的摄食。2)营养盐和光照的增强显著促进DCM层浮游植物的生长,并增加大粒级浮游植物的占比;而光照和营养盐变化对表层浮游植物的生长和粒级结构的改变相对不明显。因此,相对表层,深层浮游植物面临较小的摄食压力,拥有更大的光照和营养盐需求潜能;当台风引发水体垂向混合后,获得营养盐补充的表层浮游植物并不能迅速生长,而获得充足光照的深层浮游植物能迅速生长,成为藻华爆发的优势种。     

Molecular and morphological identification of an uncommon centrolophid fish

The use of both morphological and molecular methods has allowed a fast and reliable species assignment of a fish that local fishermen with over thirty years of experience had never seen before. The identified species, Schedophilus medusophagus, is rare along Italian coasts, and this is the first documented record in the Central Tyrrhenian Sea for over 35 years. Its abundance should be evaluated on a continuous basis, as it might reflect biological consequences of environmental and climatic change. The mitochondrial sequences obtained in this study constitute a useful molecular tag for future research and may contribute to the phylogenetic debate on the status of the genus Schedophilus, of which S. medusophagus is the type species. Based on the existing literature, these preliminary molecular data support the hypothesis that the genus is not monophyletic.     

Molecular identification of a glucose transporter from fish muscle

In mammals and birds, several isoforms of facilitative glucose transporters have been identified (GLUT1-4), but no information is available regarding the molecules involved in glucose transport in other vertebrates. Here we report the cloning of a GLUT molecule from fish muscle with high sequence homology to GLUT4 and containing features characteristic of a functional GLUT. Fish GLUT is expressed predominantly in skeletal muscle, kidney and gill, which are tissues with known high glucose utilization. These results indicate that fish GLUT is structurally, and perhaps functionally, similar to the other known GLUTs expressed in muscle in mammalian and avian species.     

Monitoring of sea surface temperature in the South China Sea

Since the early 1980s, the Malaysian Meteorological Service (MMS) has made concerted efforts to build up adequate meteorological data base for the South China Sea and the Straits of Malacca. Close rapport with local oil companies and universities has enabled MMS to widen its sources of such data.This data base has been used to carry out a study on the influence of the sea surface temperature (SST) variations in the South China Sea on the atmosphere during the northern hemisphere winter. Encouraging results of the study has prompted MMS to initiate real-time monitoring of the SST in the South China Sea. These data are available to local scientists who are interested in studying the effects of such variation on marine life in the Malaysian Exclusive Economic Zone (EEZ).