Temporal and spatial distributions of dominant shrimp stocks and their relationship with the hydrological environment in the East China Sea

To provide a scientific and technological base for fishery administration, holding a moratorium on fishing, and combating habitat degradation, a shrimp stock survey was carried out in May, August, and November 1998 and in February 1999. The study was conducted in the area between 26o00′ N and 33o00′ N and to the west of 127o00′ E in the East China Sea using a multi-sac trawl-net, with 115 stations being sampled. Up to 2001, we had found 121 species, which belong to 63 genera under 22 families, and 41 species are of high economic value and in great abundance. Nine shrimp species were of great economic importance, whose stock accounted for 76.8% of the demersal total. They were Parapenaeus fissuroides, Metapenaeopsis philippi, Palaemon gravieri, Metapenaeopsis barbata, Solenocera koelbeli, Solenocera crassicornis, Trachypenaeus curvirostris, Solenocera melantho and Parapenaeopsis hardwickii (listed in stock order). The nine species belong to the eurythermal and eurysaline community and high thermal and high saline community, had different migration patterns and stocks, and their distribution patterns could be generally classified into three types:(1) dominating in the north or the south;(2) dominating to the north of and in the coast to the south of 30o00′ N;and (3) dominating to the east of 60 m isobath, which were related to six water masses in the ECS near two lines, i.e., the 60 m isobath and 30o00′N latitudinal lines. Densely habited shrimps were found in all four seasons due to temperature and salinity frontiers and upwelling. The general stock density index was relatively higher in spring, summer, and autumn, when it surpassed 10 kg/h, while in winter, it was only 6.8 kg/h which might be caused by overfishing. According to the spawning areas of the nine species and their distribution patterns, to attain sustainable development of the shrimp fishery in the ECS, it is imperative to protect fishing areas and to hold a moratorium on catching to the west of 60 m isobath from April through October, and between 60 m and 100 m isobaths and to the south of 30oN from June through August and to limit fishing in winter.     

DISTRIBUTIONS OF CHEMICAL ELEMENTS WITH RELATION TO MAJOR WATER CIRCULATIONS IN THE CENTRAL AND NORTHERN PARTS OF THE TAIWAN STRAIT

Data obtained from a comprehensive multidisciplinary oceanographic survey in the central and northern parts of the Taiwan Strait, 24°20′-26°00′N, 118°45°-121°00′E by the Fujian Institute of Oceanology during the period May, 1983 through May, 1984, showed that the distributions of dissolved oxygen (DO), nitrate, dissolved inorganic phosphate and silicate concentrations here had obvious areal and seasonal characteristics that were mainly influenced by the seasonal circulation ofthree major water systems in the Taiwan Strait-- the Taiwan Strait Warm Water (TSWW), theZhejiang-Fujian Coastal Water (ZFCW), and the Northeastern Strait Warm Water (NESWW).     

Optimal salinity for dominant copepods in the East China Sea, determined using a yield density model

From 1997 to 2000, four field surveys were conducted in the East China Sea (ECS) (23°30′–33°00′N, 118°30′–128°00′E). A field data yield density model was used to determine the optimal salinities for 19 dominant copepod species to establish the relationship between surface salinities and abundance of those species. In addition, ecological groups of the copepods were classified based on optimal salinity and geographical distribution. The results indicate that the yield density model is suitable for determining the relationship between salinity and abundance. Cosmocalanus darwini, Euchaeta rimana, Pleuromamma gracilis, Rhincalanus cornutus, Scolecithrix danae and Pareucalanus attenuatus were determined as oceanic species, with optimal salinities of >34.0. They were stenohaline and mainly distributed in waters influenced by the Kuroshio or Taiwan warm current. Temora discaudata, T. stylifera and Canthocalanus pauper were nearshore species with optimal salinities of <33.0 and most abundant in coastal waters. The remaining 10 species, including Undinula vulgaris and Subeucalanus subcrassus, were offshore species, with optimal salinity ranging from 33.0–34.0. They were widely distributed in nearshore, offshore and oceanic waters but mainly in the mixed water of the ECS.     

Response of the equatorial western Pacific thermohaline structure to wind variation

During the Global Weather Experiment oceanographic measurements were recorded during winter and summer in the western Pacific region 5°S−5°N, 160°E−175°E. The variations of the upper ocean temperature and salinity fields were produced by the large seasonal and spatial wind fluctuations. The vertical temperature structure of the thermocline at the equator, the meridional slope of the thermocline south of the equator, and the northward penetration of high salinity water were related to the direction and intensity of the zonal wind-stress. (NOAA Pacific Marine Environmental Laboratory) Contribution No. 1307 from the Institute of Ocean., Academia Sinica. Received Sept. 3, 1985     

A STUDY ON THE RELATIONSHIPS OF THE NUTRIENTS NEAR THE CHANGJIANG RIVER ESTUARY WITH THE FLOW OF THE CHANGJIANG RIVER WATER

Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang's annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.6×104     

Fishery resources in arid zone mangroves in gulf of Kachchh, Gujarat, northwest coast of India

The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, from January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99 kg h⁻¹. It was low during monsoon (July to October), which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period (May to August). Surface water temperatures varied from 17 °C to 37 °C. Salinity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 mL L⁻¹. The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.     

Characteristics of Light Transmission in Summer and Winter and Its Relation to Sediment Transport in the East China Sea

INTRODUCTIONTheSubeiShoalandtheChangjiangRiverestuarineareainthewestoftheHuanghaiandEastChinaSeasisoneofthemarginalseasintheworld ,wheresuspendedmatterisextremelyhigh .Here ,notonlyistheretheTaiwanWarmCurrentoneoftheKuroshio’sbranchesintheEastChinaSea,butalsotheHuanghaiCoastalCurrent,andChangjiangDilutedWater.Sothestrongmixingbetweenthecoastalandoffshorewaterscomplicatessuspendedmatterdistributioninthisarea.HowthesuspendedmatterdischargedfromtheChangjiangRiverandtheabandonedHuan…     

Numerical Simulation of Wintertime Mesoscale Eddies in the East China Sea

INTRODUCTIONAnimportantachievementofoceanographysincethe 1960swasthediscoveryofmesoscaleed dieswithspatialscaleofhundredsofmeters,andtimescaleofhours;andaverageflowvelocityofabout 10cm s.Theenormousenergyofthemesoscaleeddyiscomparabletothatofacycloneoran ticycloneintheatmosphere .Themesoscaleeddyisoneoftheimportantfactorsthatdecidethechangeoftheocean .Intherecentdecades,ChineseandforeignscientistshavedonelotsofworkontheEastChinaSeasmesoscaleeddies,theformationmechanismofwhicharethefocuso…     

Size-fractionated phytoplankton biomass in autumn of the Changjiang （Yangtze） River Estuary and its adjacent waters after the Three Gorges Dam construction

A cruise was undertaken from 3rd to 8th November 2004 in Changjiang （Yangtze） River Estuary and its adjacent waters to investigate the spatial biomass distribution and size composition of phytoplankton. Chlorophyll-a （Chl-a） concentration ranged 0.42-1.17 μg L^-1 and 0.41-10.43 μg L^-1 inside and outside the river mouth, with the mean value 0.73 μg L^-1 and 1.86 μg L^-1, respectively. Compared with the Chl-a concentration in summer of 2004, the mean value was much lower inside, and a little higher outside the river mouth. The maximal Chl-a was 10.43 μg L^-1 at station 18 （122.67°E, 31.25°N）, and the region of high Chl-a concentration was observed in the central survey area between 122.5°E and 123.0°E. In the stations located east of 122.5°E, Chl-a concentration was generally high in the upper layers above 5 m due to water stratification. In the survey area, the average Chl-a in sizes of 〉20 μm and 〈20 μm was 0.28 μg L^-1 and 1.40 μg L^-1, respectively. High Chl-a concentration of 〈20 μm size-fraction indicated that the nanophytoplankton and picophytoplankton contributed the most to the biomass of phytoplankton. Skeletonema costatum, Prorocentrum micans and Scrippsiella trochoidea were the dominant species in surface water. The spatial distribution of cell abundance of phytoplankton was patchy and did not agree well with that of Chl-a, as the cell abundance could not distinguish the differences in shape and size of phytoplankton cells. Nitrate and silicate behaved conservatively, but the former could probably be the limitation factor to algal biomass at offshore stations. The distribution of phosphate scattered considerably, and its relation to the phytoplankton biomass was complicated.     

NUTRIENTS NEAR THE ARCTIC POLE REGION

The distributions of SiO_3-Si, PO_4-P, NO_3-N and NO_2-N concentrations in the seawater, iceand snow from 82°45′21″W, 88°01′20″N to the North Pole are reported and the exchange of thenutrients among the seawater, ice and snow are discussed. The average concentrations of the nutrients inthe seawater near the North Pole were 4.9±2.4μmol/L for SiO_3-Si; 0.60±0.10μmol/L for PO_4-P,3.4±1.7μmol/L for NO_3-N and 0.13±0.04μmol/L for NO_2-N. The nutrient concentrations inthe ice and snow in the North Pole were 0.20 and 0.65μmol/L for SiO_3-Si; 0.22 and 0.25μmol/L forPO_4-P; 1.6 and 5.8μmol/L for NO_3-N, 0.19 and 0.15μmol/L for NO_2-N.     

Benthic Macrofaunal Assemblage in the Arid Zone Mangroves of Gulf of Kachchh - Gujarat

The total benthic macrofauna consisting of 62 species in 5 groups, viz. crustaceans （18）, gastropods （17）, bivalves （16）, polychaetes （9） and fishes （2）, was recorded in western Kachchh mangroves near Gujarat. The population densities of benthic macrofauna ranged from 424 to 2393 ind.m^-2, the diversity ranged from 1.84 to 2.45 bits ind.^-1, the richness varied between 0.82 and 0.98, and the evenness varied between 0.64 and 0.81. Two maximum diversity values were recorded during winter and summer. The salinity ranged from 34 to 44, temperature varied between 17 and 37 ℃, and the acidity ranged from 7 to 8.9.     

Effects of reduced salinity on oxygen consumption and ammonia-N excretion ofChlamys farreri

Effects of reduced salinity on the oxygen consumption rate (OCR) and the ammonia-N excretion rate (AER) of scallopChlamys farreri (3.2–5.9 cm in shell height, 0.147–1.635 g in soft tissue dry weight) were studied in laboratory from March 21, 1997 to April 16, 1997. Under the controlled conditions of reduced salinity from 31.5 to 15.0 and ambient temperature 17°C and 23°C, the concentrations of dissolved oxygen and ammonia-N were determined by the Winkle method and the hypobromite method, respectively. Results showed that with controlled reduced salinity, the mean values of the OCR were 2.17 mg/(g.h) at 17°C, and 2.86 mg/(g.h) at 23°C and that the mean values of the AER were 178.0 μg/(g.h) at 17°C and 147.0 μg/(g.h) at 23°C. The OCR and the AER decreased with reducing salinity from 31.5 to 15.0 both at 17°C and 23°C. The effects of reduced salinity on the OCR and the AER of scallopC. farreri could be represented by the allometric equation and the exponential equation, respectively. Contribution No. 3295 from the Institute of Oceanology, Chinese Academy of Sciences. Project supported by the National Ministry of Science and Technology of China and by the Chinese Academy of Sciences, Grant No. 96-922-02-04 and KZ951-A1-102-02.     

Changes in the Contents of ATP and Its Related Breakdown Compounds in Various Tissues of Oyster During Frozen Storage

The changes in the contents of adenosine 5’-triphosphate (ATP) and its related breakdown compounds were investigated in the adductor muscle, mantle, gill and body trunk of oyster (Crassostrea gigas) during frozen storage at -20℃ and -30℃ and compared with that of the fresh oyster. The investigation was performed using an HPLC system. Different extents of ATP decomposi- tion were found in various tissues frozen at the two temperatures. The K, K’ and A.E.C values were calculated as the chemical fresh- ness indices. Considering the results of sensory evaluation, the A.E.C. value in body trunk at -20℃ and -30℃ could be used as the best freshness index for frozen oyster.     

Seasonal variation in fatty acid composition of seston and the copepod Calanus sinicus (Brodsky, 1962) in Jiaozhou Bay and its trophic implications

The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay. Principal component analysis was carried out to ordinate the fatty acid patterns of seston in stations and months. The results showed that diatoms were most abundant in the phytoplankton at station A5 (located in the northwest of the bay:36°9′N, 120°20′E) and least abundant at station D7 (located outside of the bay: 35°59′N, 120°26′E). By contrast, dinoflagellates were most abundant at station D7 and least abundant at station A5. According to the annual variations of 16:1ω7 and 18:4ω3/ 16:1ω7, diatoms flourished mainly in spring and summer, while dinoflagellates bloomed exclusively in summer. A distinctive feature of the fatty acid composition of C. sinicus was the prevalence of 20:5ω3 and 22:6ω3. The higher content of 16:1ω7 over 18:4ω3 in females indicated that diatoms contributed more than dinoflagellates to the diet of C. sinicus. The feeding intensity of C. sinicus on diatoms was higher in spring and autumn than in other seasons. The herbivorous indicators 20:1 and 22:1 were comparatively low, suggesting that besides phytoplankton, C. sinicus might feed on a wider range of particles including organic detritus, bacteria and small copepods.     

Study on the dominant species of Pteropoda in East China Sea

1 INTRODUCTION Pteropoda is a group of marine pelagic mol- lusks, which belongs to Opisthobranchia of Gastro- poda. Although Pteropoda is not a major group in pelagic zooplankton in terms of abundance and number of species, their ecological characters are…     

FRESH SNOW CHEMISTRY FROM HIGH MOUNTAIN REGIONS IN CENTRAL HIMALAYAS

Investigations of atmospheric composition in the Himalayas has been limited in both temporal and spatial scales, mainly due to difficult logistics. Ideal sites for monitoring atmospheric composition and its evolution should be free from local pollution and representative of the remote troposphere (HUEBERT et al., 1980). As the Himalayas are far removed from highly industrialized regions they provide suitable locations to monitor the chemistry of the remote troposphere and to study the evolu…     

A singular spectrum analysis on Holocene climatic oscillation from lake sedimentary record in Minqin Basin, China

The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.     

Effects of temperature on oxygen consumption and ammonia—N excretion ofChlamys farreri

Effects of temperature on oxygen consumption rate (OCR) and ammonia—N excretion rate of scallopChlamys farreri (1.7–6.2 cm in shell height) were studied in laboratory from Dec. 30,1996 to Jan. 28,1997. Under the controlled conditions of ambient water temperature 10–31°C and salinity 32, the concentrations of dissolved oxygen and ammonia—N were determined by the Winkle method and the hypobromite method, respectively. Results showed that the OCR ranged from 1.20 mg/g (DW) · h to 5.76 mg/g (DW) · h. The OCR increased with temperature from 10°C to 23°C, but at 28°C the OCR of mature individuals decreased, and that of different size scallops reduced at 31°C. The ammonia—N excretion rate ranged from 113.03 μg NH₄-N/g (DW) · h to 486.63 μg NH₄-N/g (DW) · h, and increased with temperature from 10°C to 31°C. Contribution No.3180 from the Institute of Oceanology, Chinese Academy of Sciences. This work was supported by the National Commission of Science and Technology of China, Grant No.96-922-02-04.     

Effect of soil salinity on cold tolerance of mangrove Kandelia candel

Analysis of cold tolerance on mangroveKandelia candel leaf growing in different soil salinity along Jiulong River Estuary in South China showed that the cold tolerance decreased as the increase of soil salinity. The lethal temperatures ofK. candel leaf were −10.4, −9.9 and −8.6 °C in Liaodong, Baijiao and Aotou, respectively. Under 1–2°C cold stress treatment on detached leaves ofK. candel, their caloric value gradually decreased, while electrolyte leakage gradually increased. The leaf's caloric value and electrolyte leakage in Aotou with higher soil salinity varied more largely than those in Liaodong with lower soil salinity. InK. candel leaf, total water content lowered a little, bound water content rose significantly and free water content dropped significantly with duration of cold stress. At the same time, reduction sugar, soluble sugar and starch content gradually decreased and sucrose content gradually increased. Bound water, free water and sucrose content inK. candel leaf from Aotou with higher soil salinity changed more slowly than those from Liaodong with lower soil salinity, but reduction sugar, soluble sugar and starch content inK. candel leaf from Aotou had faster variations than those from Liaodong. These data indicated that soil salinity can reduce cold tolerance ofK. candel leaf by increasing negative effect of salt ions in cell membrane, inhibiting variations of water content, and aggravating consumption of material and energy. Supported by the Found for Outstanding Young Teacher, the Ministry of Education, China.     

Heterotrophic bacterial flora in aquaculture area around Xuejiadao

From Oct., 1999 to Oct., 2000, the heterotrophic bacterial flora in the aquaculture area around Xuejiadao was investigated. The result shows that the populations of the heterotrophic bacteria are heavier in summer and autumn than those in winter and spring. The average populations in seawater, sediment, the surface of seaweed and the surface of fish are 1.4×10⁴cfu mL⁻¹, 5.4×10⁶cfu g⁻¹, 1.5×10⁶cfu g⁻¹ and 1.8×10³cfu cm⁻², respectively. A total of 301 strains were isolated, among them 259 were Gram-negative. All the Gram-negative bacteria belong to 13 genera and some genera of Enterobacteriaceae. The communities of bacteria are slightly different among the samples. In the body surface of fish, Genus vibrio is dominant. In the remaining samples, dominant genus is Aeromonas.