最新刊期
期 39 ， 1997
- 摘要：The distribution of chlorophyll a (ChL.a) concentration, primary production and new production were observed in Laizhou Bay of Bohai Sea in spring and neap tides during July 1997. The results showed that there were marked features of spatial zonation in the surveyed area, due to the differences between the geographic environment and the hydrological conditions. Chl. a, primary production and new production were all higher in spring tide than in neap tide in Laizhou Bay. The highest values of these parameters were encountered in the central coastal regions of the Bay. In most stations. Chl. a concentrations at the bottom were higher than that at the surface. The results of size-fractionated Chl. a and primary production showed that contributions of nano-plus pico-plankton (<20 μm) to total Chl. a and primary production were in dominant position in the phyto-plankton community biomass and production of Laizhou Bay. The major sources of nitrate of Laizhou Bay were terrestrial input and resuspension of the sediments in the estuary area. The environmental factors, governing primary production and new production in this sea area are discussed and comparisons of primary production and new production between spring tide and neap tide Laizhou Bay and other sea areas are also given.关键词：chlorophyll a;primary production;new production
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发布时间：2023-04-28 - 摘要：The distribution of the abundance of phytoplankton, chlorophyll a concentration and primary productivity in the northern South China Sea and the Beibu Gulf were observed in August,1999. The results showed that there were marked features of spatial zonation in the surveyed area due to the differences between the geographic environment and the hydrological conditions. Chlorophyll a value were higher near the Zhujiang (Pearl) River and lower near the eastern Hainan Island and southeastern Hong Kong at the northern South China Sea. Chlorophyll a in the surface decreased from nearshore to the mouth of the Beibu Gulf and the mean value in the water column were low at the center and mouth of the Beibu Gulf. The average concentration of chlorophyll a, primary productivity, and abundance of phytoplankton in the northern South China Sea and the Beibu Gulf were (2.03±1.18) and (0.69±0.39) mg/m3, 88.7 and 233.7 mgC/(m2·d), 0.38×106~1233.18×106 and 2.10×106~47.88×106cel/m3, respectively. The results of the size- fractionation showed that the contribution of picoplankton (<2μm) to total chlorophyll a and total primary productivity were in dominant position in phytoplankton community biomass and production of the northern South China Sea and Beibu Gulf. Nanoplankton (2-20 μm) were less, and netplankton (>20μm) the least.
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发布时间：2023-04-28 - 摘要：During June 1997 cruise by the R/V Science No.1, observations on temporal and spatial variations of size-fractionated phytoplankton standing stock and primary production were carried out in the Bohai Sea. Size-fractionated chlorophyll a and primary production, PAR (photosynthetically available radiation), as well as the related physico-oceanographic and zooplanktonic parameters were measured at five time-series stations representing sub-areas of the sea. Results obtained showed that there were marked spatial zonation of chlorophyll a and primary production in the Bohai Sea. The values in Laizhou Bay, Liaodong Bay and Bohai Bay were high and appeared closely related with tidal fluctuations, i.e. high chlorophyll a concentration occurred during high tide in Laizhou Bay, and during low tide in Liaodong Bay and Bohai Bay. In the mouth and the central region of the Bohai Sea, the values were relatively low and no relationship with tidal fluctuation could be found. Chlorophyll a concentration vertically decreased from surface to bottom in Liaodong Bay and Bohai Bay, while it increased in Laizhou Bay, the mouth, the central region of Bohai Sea, and maximized at the bottom. Size-fractionation results showed that nano-and picoplankton (< 20μm) predominated in the Bohai Sea phytoplankton communities during late spring. The average contribution to total chlorophyll a in each station was 76%-95% (mean=87%). The contribution of net (>20μm), nano-(2-20μm) and picoplankton (<2μm) were 13%, 63% and 24% to total production, and 9%, 53% and 38% to total chlorophyll a, respectively. It proved the importance of nano-and picoplankton in phytoplankton communities in the Bohai Sea ecosystems. The paper also discussed the factors, such as light intensity, zooplankton grazing pressure, etc. governing standing stock and production of phytoplankton in the Bohai Sea.
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发布时间：2023-04-28 - 摘要：The central and southern parts of the Bohai Sea was investigated by the authors during a cruise by the R. V. Dongfanghong No. 2 in September and October, 1998 and April and May, 1999. Except for larval zooplankton, 53 zooplankton species were identified. Labidocera euchaeta, and Sagitta crassa dominated in autumn, 1998. While Calanus sinicus, Centropages mcmurrichi dominated in spring, 1999. Copepods accounted for 32%-83% of the total mesozooplankton abundance in the 4 investigations. S. crassa accounted for 33%-38% of the total abundance in autumn. A medusa, Rathdea Octopunctata, occurred in abundance at some stations in spring, 1999. The maximum abundance of C. sinicus was 249 and 1442 ind./m3 in autumn and spring respectively. The maximum abundance of L. euchaeta and S. crassa in autumn was 494 and 283 ind./m3, respectively. In the spring, the abundance of C. mcmurrichi reached its maximum of 2605 ind./m3. The biomass (wet weight in mg/m3) of zooplankton ranged from 26-488 ind./m3 (143 ind./m3 on average) in Sep 1998, 35-477 ind./m3 (167 ind./m3 on average at 30 stations) in Oct 1998, 36-1257 ind./m3 (293 ind./m3 on average) in Apr 1999 and 88~916 ind./m3 (321 ind./m3,on average) in May 1999.
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发布时间：2023-04-28 - 摘要：Simulation experiments showed that the change of zooplanktonic species composition and abundance were larger than those of phytoplankton. In the stationary state, cladoceran and copepod comprised 23.1% of zooplankton abundance. The water was transparent to the bottom, and mean suspended solids was 2.85 mg/L. These conditions were favorable for cladoceran and copepod because they could freely filter food. The low abundance of protozoa and rotifera was probably caused by feeding pressure from cladoceran. From stationary state to low-flow state, the abundance of protozoa and rotifera reached 1250 and 250 ind./L, respectively. Cladoceran and copepod abundance decreased to 6 and 4.8 ind./L, respectively. AT the low-flow state, zooplankton abundance reached the maximum value in the experiment. Water column transparency was 65 cm, and mean concentration of suspended solids was 12.04 mg/L. This provided sufficient food items for protozoa and rotifera and allowed their populations to increase dramatically. However, the suspended particles caused clogging of the mouth of the cladocera, and they died within 3 days. Zooplankton abundance decreased during the period from low-flow to high-flow. Water column transparency decreased to 25 cm. When the suspended solids increased to 42.65 mg/L. The dominant species of protozoa were Difflugia acuminata and D. Pyriformis. Their shells were composed of chitin adhered to by inorganic particles. The high-flow conditions forced the benthic cladoceran Macrothrix rosea and harpacticoid copepods into the water column. These were the dominant cladocerans and copepods, respectively. This experiment showed that wind-driven physical forces play an important role in plankton community structure. Wave action has direct effect on community structure by forcing benthic cladocerans and copepods into the water column. Indirect effects included clogging of the mouths of cladocerans leading to their death. Wind-driven wave action increases suspended solids in large, shallow lakes with soft sediments and decreases water column transparency. At the same time, wave action causes nutrients to be released from the sediments into the water column. This allows an increase in algae abundance. Under certain conditions like the low-flow state, an increase in suspended solids can stimulate population growth of protozoa and rotifera, but decrease the fiaction of cladoceran and copepods which are important in controlling algal abundance via grazing. This could contribute to eutrophication in the lake. When wind-driven wave action is too high, photosynthesis inhibited by increased turbidity and algal abundance decrease. This simulation experiment showed that wind-driven wave action affected transparency, nutrient concentration and population structure of lake plankton communities. These factors could have an important role in lake eutrophication.关键词：zooplankton;community structure;simulation
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发布时间：2023-04-28 - 摘要：The average phytoplankton biomasses are 116.7mg/L during the prophase of rotifer peak occurrence, 62.1 mg/L during the peak phase in 8 experimental rotifer ponds. Some smaller algaes, such as Chlorella and Chroomonas, were major species during the prophase. But larger algae such as Euglena viridis, however, were dominant species comprising 85% of the total biomasses during the peak phase. The average zooplankton biomasses was 100.2 mg/L in the semi-stagnant ponds and 67.2 mg/L in the stagnant ones, Where Brachionus plicatilis was the only dominant species of zooplankton comprising about 85% of the total zooplankton biomasses. The diversity indices of phytoplankton were 2.53 and 2.98 during the prophase and the peak phase, respectively, while that of zooplankton were 0.56 in semi-stagnant ponds, and 0.38 in stagnant ponds. The spatiotemporal distributions of zooplankton showed regularity. The biomasses dynamics of phytoplankton was shown a “U” type, and the biomass change of rotifer conforms to the logistical curve. The biomasses of flagellate algae in the upwind zone exceeded that in the downwind zone; the biomasses on the surface exceeded that at the bottom. The biomasses of non-flagellate algae show no distinction not only between the upwind zone and the downwind zone, but also between the surface zone and the benthic zone. In the depletive state of oxygen the biomasses of rotifers and copepods in the downwind zone are more than those in the upwind zone, and the benthic biomasses are more than upper those. The features of plankton species composition and biomass, the food-supply capacity of phytoplankton and rotifer, and some regulations and reasons for plankton distributions in the rotifer ponds were discussed.
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发布时间：2023-04-28 - 摘要：Abundant invertebrates of various ecological types live in the Rizhao coastal area’s wide inter tidal zones characterized by different configurations before 1990. Since the 1990s, however, development of coastal tourism, construction of power plants and docks, creation of field by enclosing beach, etc. caused great changes of the coastal environment. Because of this, the zoobenthic com munities and number of economically valuable animals in the tidal zones showed obvious changes. The animal community change was reflected by the almost complete disappearance of some animals such as Acanthochiton rubrolineatus, Arenicola brasiliensis, Notoacmea schrencki, Littorina brevicula, Vignadula atrata, Ostrea cucullata, Chthamalus challengeri, Ligia exotica, Ocypode stimpsoni, Scopimera globosa in the upper part of the tidal zone, as a result of their migration to the low and middle parts. Among the economically valuable animals, crabs (such as Portunus trituberculatus, Charybdis japonica, Hemigrapsus penicillatus, Helice tientsinensis, Gaetice depressus, Macrophthalmus japonicus, Matuta planipes) decreased by more than 50%; and shellfishes (such as Rapana venosa, Thais clavigera, Neverta didyma, Lunatia gilva, Sca pharca subcrenata, Mytilus edulis, Ostrea denselamellosa, Mactra sulcataris, Meretrix meretrix, Solen gouldii, Nuttallia olivacea) also decreased strikingly.关键词：tidal zone;habitat;zoo-benthic communities
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发布时间：2023-04-28 - 摘要：This paper reports the quantitative dynamics of macrobenthic fauna in JiaoZhou Bay. The materials studied were collected seasonally from 10 stations in the period from February 1998 to November 1999. Among the 195 species of macrobenthic fauna collected, 79 were Polychaeta species, 39 were Mollusca species, 52 were Crustacea species, 8 were Echinodermata species, 17 were species of all other groups. The average total biomass was 151.18g/m2 and total density was 386.3 ind./m2 which were twice and 2.9 times that of 5 years ago respectively. The highest biomass occurred in autumn, being 240.32 g/m2, and the lowest biomass was in spring, being 62.97g/m2, while the highest biomass occurred in spring and the lowest biomass in winter 5 years ago. The highest density was in spring, being 515.10 ind./m2, and the lowest density was in summer, being 270.75 ind./m2, while the highest density was in summer and lowest density in autumn of 5 years ago. Mollusca and Polychaeta were the key contributors to biomass and density respectively.关键词：Jiaozhou Bay;macrobenthos;quantitative dynamics
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发布时间：2023-04-28 - 摘要：Nansha Islands and Xisha Islands comprise the two largest coral reef archipelagoes in the South China Sea. Biota study on the Xisha Islands started from the 1950’s. Many papers about the fauna and flora there have been published. Biological expeditions to the Nansha Islands started later, and biota study there, compared to that in the Xishas, is also less. The present paper compares with the benthos between the two archipelagoes. The reported families, genera and species number are 309, 663+, 1570 in the Xisha Islands and 309+, 837, 1444 in Nansha Islands. Although benthos study on the Nansha Islands is less than that on the Xisha Islands, the rich species in the Nanshas indicates that the biodiversity there is higher than that in the Xisha Islands. Because stronger and stronger human activities, and global warming, the coral death in the Nansha Islands is much more than before, and the organisms living in coral reefs are also less and less. Research on the biodiversity and protection of coral reefs in the Nansha Islands should be strengthened.关键词：Nansha Islands;Xisha Islands;benthos
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发布时间：2023-04-28 - 摘要：Marine fouling causes significant increase in the hydrodynamic loading of offshore structures, impedance of operational requirements and the alteration of corrosion characteristics, resulting in annual losses of millions of dollars. Thus understanding the phenomenon of marine fouling specific to a region is an essential prerequisite for designing and constructing both fixed &floating offshore structures and establishing appropriate cleaning programs. To meet the need for the development of the offshore oil industry, an investigation on marine fouling in offshore areas west of Dongsha Islands, northern South China Sea, was conducted from April 1988 to October 1990. The Marex hydrological buoy system (Station ZM3) was deployed in 325 m depth water 60 n miles offshore, and Station A3 was located in 345 m depth water 63 n miles offshore. At Station A3, test panels on iron frames were hung on the mooring system at depths of -1m, -10 m, -25 m, -50 m, -100 m and -150 m, and exposed for 4, 8 & 12 months, respectively. Data on fouling species and biomass were obtained by examination of test panels, buoys and the mooring systems. The results showed that in the above-mentioned waters, a total of 91 species were collected and identified from fouling communities. Of them, the dominant species were pedunculate barnacles, hydroids and algae. Oysters, pearl oysters and acorn barnacles were important fouling species, and their biomass proportions increased through time. Characteristic shifts of species composition with depth were observed also. For example, Lepas anatifera and L.anserifera mainly distributed from 0 m to -25 m. Conchoderma hunteri was found in the range of -10~-150 m, and the maximum values of the density and biomass occurred at -67. 5m. As for acorn barnacles, a total of 9 species were collected. Hoowever, Balanus reticulatus, a common species in coastal waters of South China, was not found at both investigation stations. Moreover, sources of hard fouling organisms and influences of hydrological conditions on the species dispersal are discussed at the end of the paper.关键词：Dongsha Islands;marine fouling
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发布时间：2023-04-28 - 摘要：Biofouling on underwater parts of man-made structures is a major economic and technical problem hindering the development of ocean engineering. It increases the hydrodynamic loading on a structure, obscures the underlying substratum to hinder under inspection, impairs the efficient operation of marine engineering systems, and worsens corrosion behavior and characteristics by providing anaerobic conditions favoring growth and activity of bacteria. Absence of or inadequate data on fouling will cost money in overdesign or in failures of structures. The increased oil and gas related development in offshore areas led to intensified study on marine fouling and its effects on the structural performance of offshore installations around the world. In order to meet the need for development of the offshore oil industry in China, extensive and intensive work on marine fouling has been conducted over the last twenty years. Related results showed that the type and extent of fouling assemblages developing on offshore installations varied with time, latitude, water depth, distance from coast, and type of man-made structures, i.e. floating or fixed. For example, the major species of fouling organisms in Bohai Sea are Garveia francisana and Corophium sp. in the early stage, and then the fouling communities are gradually dominated by Mytilus edulis, Sagartia rosea, Ostrea denselamellosa, Hiatella orientalis, Membranipora grandicella, Hydroides ezoensis and Balanus uliginosus. As for the offshore oil development areas of the northern South China Sea, the fouling assemblages are usually composed of pedunculate barnacles, hydroids, common oysters, pearl oysters and acorn barnacles. With increasing distance from shore, pedunculate barnacles and hydroids became more important, and the species number and biomass of littoral species occurring in the coastal waters decreased greatly. Moreover, pedunculate barnacles only distributed on objects floating and moving with wave and current. On the submerged surfaces of fixed marine structures, the fouling communities were characterized by hard foulers such as common oysters, pearl oysters and acorn barnacles. For effectively assessing the potential impact of biofouling on marine facilities and for establishing appropriate cleaning (or prevention) procedures, further work should be focused on long-term fouling communities, and then be extended to mathematical modelling and its application. Related results could have valuable industrial applications, and also be used as a powerful tool by ecologists in their ecosystem studies. Additionally, in potentially fruitful areas for exploitation of new offshore gas and oilfields where the phenomenon of fouling has received little attention, related investigation should be conducted in advance.关键词：biofouling;prevention
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发布时间：2023-04-28 - 摘要：Based on the history materials of Calanus sinicus in Taiwan Strait and its Adjacent sea areas, the distribution and reproduction of C.sinicus were researched. The results show that C.sinicus distributed all year round, in north and middle parts of Taiwan Strait, but seasonally in south part of Taiwan Strait and Xiamen Harbour. The number of C.sinicus in these regions attainted its great maximum in spring. Secondary maximum in winter, and minimum in autumn even disappeared. The abundance of C.sinicus is more near shore than off shore, more in the north than in the south in horizontal distribution. C.sinicus distribute from bottom layers to surface layers, but its adults live in bottom layers in summer and in upper layers up 35m in winter. Diurnal vertical migration of C.sinicus is marked. There were three main breeding period (i.e. 3 generations) in Taiwan Strait and Xiamen harbour. The relative questions were discussed in this paper.关键词：Calanus sinicus;Taiwan Strait;stribution and reproduction
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发布时间：2023-04-28 - 摘要：Early sex differentiation of Chinese shrimp Penaeus chinensis was studied through scanning electronic microscope techniques and histological methods. The results showed that differentiation of external sex characteristics in P.chinensis began on the 35th day after the first stage of postlarvae, while sexual discrimination of the gonad through histological methods was possible for the first time on the 76th day after the first stage of postlarvae. This result indicates that sex manipulation should be done before the 35th day after the first day of postlarvae of Penaeus chinensis.
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发布时间：2023-04-28 - 摘要：The remained 6-DMAP in treated eggs during polyploid induction by 6-DMAP in Penaeus chinensis and Eriocheir sinensis was detected using high performance chromatography (HPLC). 100% triploid embryos were induced by inhibiting the second polar body using 300 μmol/L 6-DMAP in fertilized eggs in P.chinensis. Tetraploid of Eriocheir sinensis could be induced using 300μmol/L 6-DMAP inhibiting the first cleavage, and the highest ratio of tetraploid checked in blastosphere stage was 58%. In HPLC detection, Waters-NOVA PAK C18 (5mm× 15mm) was used, and methanol:water (1:1) was used as dilution. 6-DMAP can be detected at 254nm, the minimum of detected 6-DMAP was 0.003μg/ml. The treated eggs rinsed thrice in seawater, the remained 6-DMAP cannot be detected in HPLC at the given condition. During the hatching period, the remained 6-DMAP was diluted and rinsed again and again. 6-DMAP can be degraded in environment. The results indicated that using 6-DMAP to induce polyploid in the eggs of Penaeus chinensis and Eriocheir sinensis is effective and safe.
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发布时间：2023-04-28 - 摘要：The authors' light and transimission electron microscopy examination of the X-organ (XO)-sinus gland (SG) complex in adult cultured Chinese shrimp (Penaeus chinensis) revealed that its SG was composed of inner sinus and outer sinus and located on the lateral side of the medulla interna and dorsal medulla terminalia separately. Only one cell type like neurosecretory cells was found in the medulla terminalia. Transimission electron microscopic examination revealed that the SG was mainly composed of enlarged axon terminals abutting on the thin basal lamina of a central hemolymph lacuna acting as a storage release centre for the membrane bound neurosecretory material. Also present in the SG were glial cells with cytoplasmic processes which enwrap the terminals. Four types of neurosecretory terminals were distinguished on the basis of size, morphology and electron density of the neurosecretory granules. Each axon terminal contained only 1 type of granule; the mean granule diameter ranged from 137 nm (type 4) to 236 nm (type 1). Neurosecretory granules exocytosis was not observed in the SG of the Chinese shrimp. To our knowledge, the villus originated from the lamina was not found in the SG of crustaceans dispite of Chinese shrimp, some images showed that villus were related with the releasing of granules from the neurosecretory granules. Examination of the SG ultrastructure showed the existence of four kinds of neuropeptides that could be separated from the SG extraction by high performance capillary electrophoresis in 50 μm i.d. X 37 cm (33cm effective length) amino-coated capillary, with 0.1 mol/L boracic acid buffer (PH 8.0) as running buffer at 18℃ and 6kv running voltage[(-)-(+)].
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发布时间：2023-04-28 - 摘要：This paper deals with 3 new species of atyid shrimps collected from China. The type specimens are preserved in Shanghai Fisheries University.关键词：new species;atyid shrimps
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发布时间：2023-04-28 - 摘要：1. Ecological colony The East China Sea has three water systems of different properties eurythermal and low-salinity water along the coastal line, high-temperature and high-salinity water in the east, low-temperature and high salinity water coming from the southern Yellow Sea bottom layer and so is rich in shrimp resource of different ecological species. Based on the ecological species inhabiting certain temperature and salinity range layers, shrimps inhabiting the ECS continental shelf can be classified into three types. 2. Faunal Characteristics As to the characteristics of shrimp fauna in the East China Sea and from the perspective of its composition, affected by the high-salinity water, tropical and warm species dominate; in the coastal water areas, affected by the land climate and freshwater from rivers, the shrimp composition was the same as that in the Yellow Sea and Bohai Sea; in the northern part affected by the lower layer cold water from the Yellow Sea, there were a few cold water species. As compared with adjacent waters, 73% of the species are commonly found in the South China Sea; 62% in Japan; 44% in South Asia; 33% in India; 29% and 20% in the Yellow Sea and Bohai Sea respectively. Hence, the shrimp fauna in East China Sea belongs to the west Pacific fauna.关键词：ecological colony;fauna characteristics;China shrimp
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发布时间：2023-04-28 - 摘要：The genome of Litopenaeus vannamei was analyzed by random amplified polymorphic DNA (RAPD) analysis to identify DNA markers for important traits in Litopenaeus vannamei in the South China. A total of 20 ten-bases primers were screened, and eight positive primers giving highly reproducible RAPD patterns were selected for comparison between healthy and diseased populations of Litopenaeus vannamei. A total of 38 reproducible RAPD fragments ranging from 200 to 1750 base pairs were scored, and 24 fragments (62.2%) were polymorphic. Only three RAPD markers, OPX-01-1020, OPX-14-530 and OPX-17-940, were found in the diseased population of Litopenaeus vannamei, suggesting the potential use of them as DNA markers for helping broodstock management and selection for breeding.
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发布时间：2023-04-28 - 摘要：Helice tientsinensis is widely distributed in coastal provinces of China. It lives in caves on the beaches of estuaries and occurs in large numbers. Its larvae naturally occur and usually mix with those of Eriocheir sinensis in the mouth of Changjiang River and the neighbouring waters. How to distinguish them from each other is important for crab culture using E.sinensis larvae captured from natural waters. This paper deals detailedly with the complete larvae development of H.tientsinensis reared in the laboratory. The present species passes through five zoeal stages before matamorphasis to the megalopal stage attained about 21 days after hatching. The culture was carried out at 20-24℃, salinity 15 and 200-400 lx photo intensity. Morphological characteristics of each larval stage of H.tientsinensis are compared with those of E.sinensi. The significant difference between the zoeae of H.tientsinensis and of E.sinensis is that the dorsal, rostral and lateral spines on the carapace are smooth in the former while those in the latter have denticles. Besides, the numbers of setae on the maxillule and maxilla of zoeae of the former are less than that of the latter. Megalopas of the two species can be briefly distinguished as follows. Firstly, there are two indistinctly rounded lobs on the antero-lateral margins of the E.sinensis carapace while there is none on those of H.tientaiensis. Secondly, pereiopod 2-4 each with 3-4 ventral teeth on dactylus of E.sinensis; 3-4 ventral spines on that of H.tientsinensis. Thirdly, the expos of pleopods 1-5 of E.inensis with 23, 21, 21, 19, 12 long natatory plumose setae; with 18, 17, 17, 16, 10 long natatory plumose setae on that of H.tientsinensi.
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发布时间：2023-04-28 - 摘要：This paper is mainly focused on a comprehensive review of the effect of salinity fluctuation on feeding, transferring efficiency and growth of fish in wide habitats, which could help our research program on the contribution of higher trophic level carnivorous Japanese sea bass, Lateolabrax japonicus, in the marine ecosystem under experimental conditions. It was found that the response of fish to salinity was directly proportional to food consumption during different life history under specific temperature, showing specific-adaptation capacity for both freshwater and marine environment. Compared with regulation to ecological efficiency, mask factor, significant divergence has occurred in the salinity regime, indicating evident relationship between specific growth rate (SGR) and salinity. Based on the analysis, we here present a tentative hypothesis that the adaptive spectrum could be reflected in the potential response to the salinity effect during specific stage to explain that optimum energy saving may be approached at the isosmotic point in the curve of salinity vs potential energy. From the viewpoint of the nonlinear relationship between salinity and ecophysiological efficiency, a process-oriented test for the hypothesis would be necessary to monitor the impact of salinity-based variation on the ecological dynamics of indicator fish in the estuary of Changjiang River.
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发布时间：2023-04-28 - 摘要：The composition and spatiotemporal dynamics of dominants within fish community in Bohai Sea system were analyzed using comprehensive data sampled in two 10-year towing periods, in order to determine the succession pattern of community and the responsive mechanism contributing to the sustainability of biological production. The 119 fish in the 1982-1985, dataset were comprised of 69 warm temperate species (57.98%), 34 warm water species (28.57%) and 16 cold temperate species (13.45%). Among these components, 31 species comprised to 53.834 thousand individuals per square kilometers in NED and 792.048 kg/km2 in BED, were determined as important fish judged by Pinaka's IRI (Index of Relative Importance), which related to the number, biomass and occurrence frequency for each species in the first sample period. Half-mouth anchovies, Setipinna taty, Japanese herring, Engraulis japonicus, spot croaker, Collichthys nivealus, and small yellow croaker, Pseudosciaena polyactics, were among the 4 dominants. Seasonal trend was shown up a single cycle around the year and the persistence measured in ISTR (index of species turnover rates) was 0.6792 between seasons. Compared with two 10-year data by same gear, community diversity during 1992 and 2000, had decreased in some aspects, such as species number, NED, BED by 38.66%, 35.46% and 46.1%, respectively. Correspondingly, seasonal persistence also decreased to 0.5902, showing that sustainability of fisheries productivity in the system is characterized by tending toward short age, weaker ecotrophic dynamics and fast turnover rate in production.
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发布时间：2023-04-28 - 摘要：The analyses of data, obtained in comprehensive surveys on the fisheries ecology and oceanography in the Changjiang River estuary May, 1999 indicated that the ichthyoplankton community structure and its spatiotemporal dynamics could be related to the construction of the Three-Gorge Dam in the upstream and the recruitment mechanism of commercial fisheries in the waters. It was showed that hydro-physical conditions in the Changjiang River Estuary are complicated with great variation in salinity and transparency. Under this variable environment, sixteen families and 20 species of ichthyoplankton were recorded with 6644 eggs and 14932 larvae in the samples. In both the vertical and surface sampling, the number of Engraulis japonicus was dominated, comprising 95.53% in the vertical water body, and 90.80% in the surface; the second was Chaeturichthys hexanema; and the third was Chaeturichthys hexanema and Hemisalanx prognathus Liza haematocheila. was the second and third in vertical waterbody; and in the surface water body, the second and third were Chaeturichthys hexanema and Coilia mystus. With regard to the index of relative importance (IRI), Engraulis japonicus was absolutely dominant component; Chaeturichthys hexanema were dominant components, with IRI of more than 100 4 regular components with IRI of 10-100 were Coilia mystus, Hemisalanx prognathus, Liza haematocheila and Pseudosciaena polyactis. Surface temperature significantly affected egg survival and occurrence in horizontal samples; the obviously close relation of zooplankton biomass to larvae development in the vertical samples could indicate the direct impact from the hydroelectric facility in the upstream Changjiang River on the developmental environment in the ecosystem.
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发布时间：2023-04-28 - 摘要：During the yolk-sac stage of the teleosts from the sea, biochemical components such as FAA, protein, FA, total lipid and carbohydrate, vary distinctly and decrease with the development. The decrement varies largely among them. This suggests that in the early development of the fish, its nutrition requirement is not the same. It may change with different species, developmental stage and survival environment. Thus if we know the exact change in the biochemical components, we can find the most appropriate food to meet the larval nutritional requirement and reduce the mortality.关键词：teleost;yolk-sac stage;nutritional requirement
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发布时间：2023-04-28
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