Otolith shape analysis for stock discrimination of two Collichthys genus croaker(Pieces: Sciaenidae,) from the northern Chinese coast

The otolith morphology of two croaker species(C ollichthys lucidus and C ollichthys niveatus) from three areas(Liaodong Bay, LD; Huanghe(Yellow) River estuary, HRE; Jiaozhou Bay, JZ) along the northern Chinese coast were investigated for species identifi cation and stock discrimination. The otolith contour shape described by elliptic Fourier coefficients(EFC) were analysed using principal components analysis(PCA) and stepwise canonical discriminant analysis(CDA) to identify species and stocks. The two species were well dif ferentiated, with an overall classifi cation success rate of 97.8%. And variations in the otolith shapes were significant enough to discriminate among the three geographical samples of C. lucidus(67.7%) or C. niveatus(65.2%). Relatively high mis-assignment occurred between the geographically adjacent LD and HRE samples, which implied that individual mixing may exist between the two samples. This study yielded information complementary to that derived from genetic studies and provided information for assessing the stock structure of C. lucidus and C. niveatus in the Bohai Sea and the Yellow Sea.     

Application of otolith shape analysis for stock discrimination and species identification of five goby species （Perciformes： Gobiidae） in the northern Chinese coastal waters

We tested the use of otolith shape analysis to discriminate between species and stocks of five goby species( Ctenotrypauchen chinensis, Odontamblyopus lacepedii, Amblychaeturichthys hexanema, Chaeturichthys stigmatias, and Acanthogobius hasta) found in northern Chinese coastal waters. The five species were well differentiated with high overall classification success using shape indices(83.7%), elliptic Fourier coefficients(98.6%), or the combination of both methods(94.9%). However, shape analysis alone was only moderately successful at discriminating among the four stocks(Liaodong Bay, LD; Bohai Bay, BH; Huanghe(Yellow) River estuary HRE, and Jiaozhou Bay, JZ stocks) of A. hasta(50%–54%) and C. stigmatias(65.7%–75.8%). For these two species, shape analysis was moderately successful at discriminating the HRE or JZ stocks from other stocks, but failed to effectively identify the LD and BH stocks. A large number of otoliths were misclassified between the HRE and JZ stocks, which are geographically well separated. The classification success for stock discrimination was higher using elliptic Fourier coefficients alone(70.2%) or in combination with shape indices(75.8%) than using only shape indices(65.7%) in C. stigmatias whereas there was little difference among the three methods for A. hasta. Our results supported the common belief that otolith shape analysis is generally more effective for interspecific identification than intraspecific discrimination. Moreover, compared with shape indices analysis, Fourier analysis improves classification success during inter- and intra-species discrimination by otolith shape analysis, although this did not necessarily always occur in all fish species.     

Analyses of egg size,otolith shape,and growth revealed two components of small yellow croaker in Haizhou Bay spawning stock

The geographic al variations in life history characteristic s of small yellow cro aker Larimich thys polyactis,caused by experienced different environmental conditions,have been observed in China seas.Previous studies based on spatial distribution,migration route,and body morphometrics suggested a complex stock structure.In this study,to clarify the source of a spawning stock,we investigated the reproduction strategy and inter-structure of the Haizhou Bay(HZB)spawning stock in the middle Yellow Sea from both egg survey and adult otolith increment analysis.Egg and adult samples were collected from three surveys during spawning season in 2013.Distinct spatial and temporal variations were detected in egg distribution and size,and otolith shape analy sis of adult fishes revealed two morphotypes with different increment growth using random forest cluster.The results indicate the existence of two components within the same spawning stock in HZB from different wintering grounds,and accordingly special protection should be required for this stock given the significance to maintain connectivity between adj acent subpopulations.     

Early life migration and population discrimination of the small yellow croaker Larimichthys polyactis from the Yellow Sea: inferences from otolith Sr/Ca ratios

Journal of Oceanology and Limnology - The small yellow croaker Larimichthys polyactis is a benthic marine fish species of high ecological and commercial importance and is widely distributed in the...     

THE HOLOCENE ALONG THE COAST OF HAINAN ISLAND, CHINA

Based on the new data of the Quaternary along the coast of Hainan Island, China, this paper puts forward that the Holocene in Hainan Island can be divided into four formations: Wanning formation (Q41), Sanya formation (Q42-1), Qiongshan formation (Q42-2) and Ledong formation (Q43). Spore-pollen analysis shows that there are 6 spore-pollen zones existed, reflecting two cycles of climatic fluctuation from warm-dry to hot-humid. The climax of hot-humid period occurred 6,000-5,000 years B.P.. Based on the 14C dating data of the 38 samples representing the positions of ancient sea level, a breakthrough curve representing the sea level change during the Holocone is obtained, in which , a sea level change caused by tectonic movement is subtracted. Two cycles of rise-drop of sea level with three periods of high sea level were found. The period with the highest sea level is some 6,000-5,000 years B.P.. According to the rise-drop rate of sea level, four periods of the sea level change can be distinguished in the     

Comparative study on the organoleptic quality of wild and farmed large yellow croaker Larimichthys crocea

Journal of Oceanology and Limnology - To fill the blank in systematic study on the organoleptic quality of large yellow croaker Larimichthys crocea, we analyzed the organoleptic quality of the fish...     

黄河下游沿岸湿地景观格局变化研究

在遥感和GIS技术的支持下,结合研究区湿地的区域特点确定沿黄湿地景观分类系统。构建了湿地景观格局变化表征模型,综合利用景观多样性指数、景观破碎化指数、景观要素斑块分布质心空间变化等景观格局指标和斑块数量,斑块面积、斑块平均面积、斑块数量等景观类型指标,比较系统地分析了近七年研究区湿地景观格局的动态变化。结果表明:①研究区湿地的分布面积呈显著下降趋势;②随着人类干扰强度的增加,景观多样性上升;③湿地景观要素中,稻田湿地、滩涂面积在减少,而水库坑塘、黄河面积都在不断增加。     

AFLP analysis of genetic variation among three natural populations of horseshoe crab Tachypleus tridentatus along Chinese coast

The AFLP(amplified fragment length polymorphism) technique was used to analyze and compare the genetic diversity of Tachypleus tridentatus from three south-eastern coastal sites of China(Pingtan,Hong Kong and Beihai).Eight pairs of primers generated 361 loci,including 285 polymorphic loci.The ratio of polymorphic loci was 96.97%.Nei's genetic diversity index was 0.420 8 and the Shannon information index was 0.607 5,both of which were higher than that reported for many other arthropods.These results show tha...     

Fouling characteristics of cnidarians (Hydrozoa and Anthozoa) along the coast of China

Journal of Oceanology and Limnology - Hydrozoans and anthozoans are an important component of a great variety of marine communities, particularly abundant and ubiquitous as part of the fouling...     

Types and distribution patterns of modern tidal channels along the Huanghe River Delta coast

INTRODUCTIONTidalchannelsareimportantgeomorphologicunitsalongsiltcoasts.Theyhaveanevidentfunc tionfortidalflatbecausetheyareassociatedwithitsrapidbayheadwarderosionandlateralswing ing.Thetidalchannelsdevelopalongthecoastandplayanimportantroleinseaandlandinterac tion .Manyscientistsresearchedthetidalchannels (Bayliss Smith ,1 978;Shao ,1 988;Zhang ,1 995) .TheScientificandTechnicalCommitteeofShandongProvince (1 991 )investigatedthecoastoftheHuanghe (Yellow)RiverDeltaandresearchedtheti…     

Correlation between coastal geomorphology and tsunami inundation along the coast of Kanyakumari, India

An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District,India to decode the influence of coastal geomorphology on inundation degree and run-up level.Even though the tsunami waves approach the study area in different patterns,the consequences are found to be mainly dependent upon the coastal configuration and local geographic setting,the study area are considered to be of three types based upon the geomorphic arrangement,namely shallow coast,elevated coast and estuarine coast.The inundation and run-up level vary from coast to coast even though there is no remarkable variation in the intensity of the approaching tsunami surge.The inundation extent ranges from to 54 m to 413 m with maximum along estuarine coast and minimum along elevated coast.Estuarine coast recorded the maximum run-up level of about 6 m and the minimum of about 1 m along the elevated coast.The percentage of inundated area in the total coastal area varies between 19% to 10% along estuarine coast and elevated coast respectively.Inundation and run-up level cannot be appreciable in the inland along the elevated coast.The beaches of elevated coast are less affected whereas those of estuarine coast are highly affected.Inundation is limited in the elevated beaches along the study area.     

Stock discrimination of spottedtail goby (Synechogobius ommaturus) in the Yellow Sea by analysis of otolith shape

Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%.     

Redox states of underground brine system along the southern coast of the Laizhou Bay

Underground brine samples were collected along the southern coast of the Laizhou Bay, Shangdong, China in two field investigations in 2003. The brines are confined in the Quaternary sediment and underwent a series of geochemical changes. The redox states of these brines were assessed qualitatively based on the measurements of Eh and redox-sensitive species such as DO, NO NO~, Mn2＋, Fe2＋, SO4^2- in the brines. The redox condition of the underground brine is anoxic, and the redox reactions that controlled the redox potential of brines should be Fe（Ⅲ） reduction and sulfate reduction.     

Sea level along the southeast coast of China during El Niño

In El Niño years, along the southeast China coast, the seasonal cycle of sea level variation—low in spring, high in autumn—is attenuated: specifically, the autumn peak is reduced by about 10 cm. This negative anomaly increases toward the south and occurs at the same time as a similar (but five times larger) sea level anomaly at Truk Island (7.5°N) in the western Pacific.     

Temporal and spatial variations in the distribution of macroalgal communities along the Yantai coast,China

To explore the impact of environmental variables on macroalgal communities, their temporal and spatial distributions were examined along the Yantai coast, China between April 2010 and March 2011. Macroalgae sampling was conducted monthly at four sites along the coast： Jiahe River estuary, Zhifu Island, Fisherman＇s Wharf, and Yangma Island. The species composition and abundance, and their relationship with environmental variables were assessed. Along the Yantai coast, 35 macroalgae species were identified, including 24 Rhodophyta spp., 7 Chlorophyta, and 4 Phaeophyta spp. Highest species numbers were recorded in the summer at all sampling sites, except in the Jiahe River estuary. Macroalgae biomass was the greatest in the summer. Year-round, the highest species number and dry biomass recorded at Fisherman＇s Wharf and Yangma Island was attributed to the substrate type. In summer, Ulva pertusa Kjellman was the dominant species identified along the Yantai coast, which indicates a risk ofmacroalgae blooms. Our results show that seawater temperature and nutrients appear to significantly affect the temporal and spatial patterns of macroalgal abundance along the Yantai coast. The effects of environmental variables on the macroalgae on the Yantai coast need further study.     

Mapping the resting cysts of dinoflagellate Alexandrium catenella along the coast of Qinhuangdao,China

Dinoflagellate Alexandrium catenella is a cosmopolitan bloom-forming species with complex life cycle, the formation and germination of resting cysts are critical for its bloom dynamics. In the coastal waters of Qinhuangdao, A. catenella has been identified as the major causative agent for paralytic shellfish poisoning, but there is little knowledge concerning its resting cysts in this region. In this study, three surveys were carried out along the coast of Qinhuangdao from 2020 to 2021 to map the distribution of A. catenella resting cysts, using a quantitative PCR (qPCR) assay specific for A. catenella. The resting cysts were detected in surface sediments during all the three surveys, and their distribution patterns were similar. High abundance of resting cysts (maximum 1 300 cysts/g sediment (wet weight)) were found in a region (119.62°E–119.99°E, 39.67°N–39.98°N) northeast to the coastal waters of Qinhuangdao, where surface sediments were mainly composed of clay and silt (percentage above 50%). Prior to the formation of the A. catenella bloom in March 2021, the abundance of A. catenella vegetative cells in seawater had extremely significant positive correlation with the abundance of resting cysts in surface sediments, reflecting the important role of resting cysts in the initiation of A. catenella blooms. As far as we know, this is the first report on the distribution of A. catenella cysts along the coast of Qinhuangdao. The results will offer a sound basis for the future monitoring and mitigation of toxic A. catenella blooms and paralytic shellfish poisoning events in this region.

     

The sedimentary characteristics and formation mechanism of shell ridges along the southwest coast of Bohai Bay

The present paper studies the sedimentary characteristics and mechanism of the shell ridges on the southwestern coast of Bohai Bay, which are the largest and have the highest shell (or shell fragment) content in the world. These shell ridges are composed of two sedimentary subfacies: the ridge subfacies and the ridge infill subfacies with different inner textures and sedimentary structures. The ridge subfacies primarily consists of fresh shells and/or shell fragments with parallel beddings and high-angle oblique beddings. The ridge infill subfacies consists of finer shell fragments and silty sand with parallel beddings oblique to land. The evolution of the shell ridge is controlled by the accumulation of substantial shell material,the relative slow erosion of shoreline, storm waves, winds and the shift of river routes. Wind tunnel tests indicate that the critical movement velocity of shell is lower than that of quartz sand of the same grain size. Deltaic progradation alternates with shell ridge growth. While the Yellow River empties into the sea through this area, accompanied by deltaic progradating, the shell material is scarce, which is unfavorable to the growth of the shell ridge. Conversely, erosion occurs along an abandoned delta coast where a shell ridge may develop, e.g. the shell ridge on the southwest of Bohai Bay.     

Cross-shelf transport induced by coastal trapped waves along the coast of East China Sea

Cross-shelf transport is important due to its role in the transport of nutrients, larvae, sediments, and pollutants. The role of coastal trapped waves(CTWs) and their contribution to the cross-shelf transport is presently unknown. The impact of wind-driven CTWs on the structure of the cross-shelf currents and transport is investigated in the East China Sea(ECS) starting from theory. The cross-shelf currents are divided into four terms: the geostrophic balance(GB) term, the second-order wave(SOW) term, the bottom friction(BF) term and Ekman(EK) term, as well as three modes: the Kelvin wave(KW) mode, the first shelf wave(SW1) mode and the second shelf wave(SW2) mode. Comparison among these decompositions shows that(1) for the four terms, the effect of the GB and EK terms is continual, while that of the BF term is confi ned to 60–240 km of fshore, and the contribution of the SOW term can be ignored;(2) for the three modes, the KW and SW1 modes are dominant in cross-shelf transport. The results show that the total cross-shelf transport travels onshore under idealized wind stress on the order of 10~(-1), and it increases along the cross-shelf direction and peaks about-0.73 Sv at the continental shelf margin. With the increase of linear bottom friction coeffi cient, the cross-shelf transport declines with distance with the slope becoming more uniform.