Embryonic development of Pelteobagrus fulvidraco （Richardson, 1846）

1 INTRODUCTION Pelteobagrus fulvidraco (Richardson, 1846) or yellow catfish is slender and scaleless with a gently sloping dorsal profile from anterior to posterior. It is generally black-brown to black-yellow on the back, light yellow on the belly, with …     

Embryonic and larval development in barfin flounder Verasper moseri (Jordan and Gilbert)

Broodstock of Verasper moseri (Jordan and Gilbert) aged 3–4 years old were selected, and reinforced cultivation was conducted to promote maturation under controlled water temperature and photoperiod conditions. Fertilized eggs were obtained by artificial fertilization, and the development of embryos, larvae and juveniles was observed continuously. The results showed that the fertilized eggs of V. moseri were spherical, with transparent yolk and homogeneous bioplasm, and had no oil globule inside. The average diameter of the eggs was 1.77±0.02 mm. The eggs of V. moseri were buoyant in water with salinity above 35. The cleavage type was typical discoidal. Young pigment cells appeared when olfactory plates began to form. Hatching occurred at 187 h after fertilization at a water temperature of 8.5°C. The newly hatched larvae, floating on the water surface, were transparent with an average total length of 4.69±0.15 mm. During the cultivation period, when the water temperature was raised from 9 to 14.5°C, 4-day old larvae showed more melanophores on the body surface, making the larvae gray in color. The pectoral fins began to develop, which enabled the larvae to swim horizontally and in a lively manner. On days 7–8, the digestive duct formed. The yolk sac was small and black. The yolk sac was absorbed on day 11. Larvae took food actively, and body length and body height clearly increased. The rudiments of dorsal and anal fin pterygiophores were discernible and caudal fin ray elements formed on day 19. On day 24, the larval notochord flexed upwards, and the rays of unpaired fins began to differentiate. Pigment cells converged on the dorsal and anal fin rays, and the mastoid teeth on the mandible appeared. On day 29, the left eyes of juveniles began to move upwards. Depigmentation began in some juveniles and they became sandy brown in color on day 37. Most juveniles began to settle on the bottom of the tank. The left eyes of juveniles migrated completely to the right side on day 50, when the average body length attained 2.5±0.18 cm, and juveniles accomplished metamorphosis to young. The embryonic and larval characters of several flounder species are compared.     

FOOD SOURCES AND CARBON BUDGET OF CHINESE PRAWN PENAEUS CHINENSIS

This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.     

Early development of Costaria costata (C. Agardh) Saunders and cultivation trials

Costaria costata (C. Agardh) Saunders is one of common kelps distributed in many coastal areas worldwide; however, in China, no reports have been made on cultivation of the genus. To investigate potential cultivation of the species in the northern part of China, trials on isolation and preservation of the gametophytes were conducted using C. costata from Korea; growth and development of the gametophytes were observed. We showed that at 10±1°C, 60 μmol m⁻²s⁻¹ and 12:12 h (L:D), freshly released zoospores settled down within 1 hour, and then developed into the primary cell during the following 2 days. After a vegetative growth phase lasting 6–8 days, female gametophytes became 3–4 times larger in diameter than that of the primary cell, but still remained at a unicellular stage, while male gametophytes divided into 4–10 cells with only a slight change in size. Fertilization occurred within 10 days after the zoospores were released from the sporangia, and the apical and basal tissues of the juvenile sporophyte divided and differentiated into the blade and stipe. Temperature and irradiance influenced gametophytic vegetative growth and developmental patterns. Generally, low irradiance (15 μmol m⁻²s⁻¹ and 30 μmol m⁻²s⁻¹) was unfavorable to the induction of fertility, but it enhanced female gametophyte division. The optimal conditions for vegetative growth were 15°C and 30 μmol m⁻²s⁻¹. After transplantation of the juvenile seedlings and after eight months cultivation, the harvested mature blade reached 194 cm in length and 32.7 cm in width. Our study proves that it is feasible to implement propagation and large scale cultivation of C. costata in northern China.     

Cryopreservation of Veliger Larvae of Trumpet Shell, Charonia sauliae： an Essential Preparation to Artificial Propagation

Trumpet shell, Charonia sauliae, is an endangered and valuable species, but its artificial propagation protocol has not been successfully established. To estimate the possibility of cryopreservation for larvae of C. sauliae, which is a potential preparation for its artificial reproduction and further research, in this study a protocol for the cryopreservation of veliger larvae of trumpet shell was optimized. Through a two-step cryopreservation procedure, four kinds of cryoprotectants (ethylene glycol, 1, 2-propanediol, dimethyl sulfoxide and glycerol) were employed at three concentrations (1.0, 1.5 and 2.0 molL⁻¹) respectively and survival rates of larvae were determined after a storage of 1h. The larvae frozen with these four cryoprotectants after 1 h storage were cultured, and then survival rates were determined at 24, 72 and 120 h after thawing. Dimethyl sulfoxide at a concentration of 1.5 molL⁻¹ showed the best protective effect in all experiments (p<0.05). And survival rates of larvae frozen with dimethyl sulfoxide were determined after 1, 7 and 15 d of storage. The survival rates of larvae frozen with 1.5 molL⁻¹ dimethyl sulfoxide after 1 h, 1 d, 7 d and 15 d of storage were 80.77% ±7.51%, 80.34% ±11.28%, 83.10% ±9.14% and 77.23% ±6.22% respectively. No significant differences in survival rates of larvae frozen with dimethyl sulfoxide were observed after various storage periods (p>0.05).     

STUDY ON EMBRYONIC DEVELOPMENT AND EARLY GROWTH OF TRIPLOID AND GYNOGENETIC DIPLOID LEFI—EYED FLOUNDER, PARALICHTHYS OLIVACEUS （T. et S. ）

The early effects of chromosomal manipulation of eggs and sperm on the yields of trip-loid and gynogenefic diploid larvae of Paralichthys olivaceus were investigated. Triploidy was achieved by cold shocking fen.ilized eggs at 0 - 2℃ for 45 minutes duration 5 minutes after fen.ilization, and the in-duced triploidy rates were 31.2% - 50% and the relative hatching rates were 53.3% - 99%. Gynnge-aetic diploids were obtained when eggs were inseminated with irradiated sperm and cold shocked at 0 -2℃ for 45 minutes duration 5 minutes after fertihzation. The induced gynogenetic diploid rates and the relative hatching rates were 94 % - 96 % and 48.5 % - 68.5 % respectively. The embryonic development of the triploid experimental group and of the gynogenetic diploid experimental group was delayed at first compared with the control group. But from the gastrula stage, it was not delayed anymore. There were no significant differences in the growth of the triploid experimental group larvae and the control group larvae, and in the growth of the gynogenetic diploid experimental group larvae and the control group larvae ac-cording to Student‘s t-test (α = 0.05). The relationship between the early growth of the triploid experi-mental group larvae and that of gynogenetic diploid experimental group larvae was also studied.     

THE DENSITIES OF CHANGJIANG ESTUARINE WATERS

The International Eq一lation of State of Seawater,1980 and the PraeticalSalinity Scale,1978 have been adoPted by theUNESCO江CES沼COR八APSOJoint Panel ono‘eanogral,hie Tables and Standards(JPOTS),and endorsed bythese organizati6ns(Miller‘〕and Poisson,1981;Uneseo,1981).Th已new equa-tion and the Praetieal Salinity Seale are to be used for all values Published fromJan .1,1982 .The new equation 15 aeeurate for use in all oeeanie surfaee waters,but eannot be aeeurately aPPlied to…     

Variations of ion-transport enzyme activities during early development of the shrimps <Emphasis Type="Italic">Fenneropenaeus chinensis</Emphasis> and <Emphasis Type="Italic">Marsupenaeus japonicus</Emphasis>

The ion-transport enzyme activities were studied in the nauplii 1–2, zoea 1–3, mysis 1–3, and postlarva 1–7 of the shrimps Marsupenaeus japonicus and Fenneropenaeus chinensis. The results showed that total ATPase, Na⁺-K⁺-ATPase, and V-ATPase (V-type H⁺-ATPase) activities increased during the early development for both the species, from zero in nauplii to stable levels after zoea stage. The enzyme activities of the latter species were significantly higher than those of the former species after zoea stage (F>F _0.05). The contributions of Na⁺-K⁺-ATPase, V-ATPase and HCO₃ ⁻-ATPase to the total ATPase activity of the two species varied in different developmental stages and accounted for 40%–70%, 22%–46% and 2%–13% in M. japonicus from zoea to postlarva stage, whilst the shares of them were 42%–69%, 28%–44% and 2.5%–22%, respectively in F.chinensis. These findings suggest the possible culture of the two species with varying water quality, especially the salinity and pH.     

Methodology for studies of carbon dynamics between phytoplankton primary production and heterotrophic bacterial secondary production

The SCENTO-System was used to study the carbon dynamics between phytoplankton primary production and heterotrophic bacterial secondary production. Most of the methods used nowadays in situ for limnological synecology studies were applied. Primary production measurement showed an increasing tendency with increasing content of chlorophylla. It provided a true photosynthetic rate lying within the range of eutrophic lakes. Net EOC released from the algae ranged from 8.5 to 27.5 μg C l⁻¹(6h)⁻¹. Accompanying the algal products the number of bacteria increased from 1.475 ×10⁹ to 8.074×10⁹ cells l⁻¹. The bacterial mean cell volume was small, between 0.0315 and 0.0548μm³. Bacterial carbon production from direct growth estimates was compared with independent calculations of bacterial growth from EOC uptake and³H-thymidine incorporation. Direct estimates were 2.97–10.0 μg Cl⁻¹ (24h)⁻¹ with the exception of a zero-growth on the third day. EOC uptake was 123.5–191.0 μg Cl⁻¹ (6h)⁻¹. That calculated from³H-thymidine incorporation was 0.2–0.5 μg Cl⁻¹ (6h)⁻¹.¹⁴C-glucose dark uptake ran parallel to the increasing bacterial biomass. The respiration of glucose was 6.5% (avg.) of the gross uptake. Since the system operated without grazing pressure, a real carbon flow from primary production to bacterial secondary production could be observed.     

Relation of body weight and food consumption to metabolic rate of juvenile Japanese sea bass,Lateolabrax japonicus

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＪａｐａｎｅｓｅｓｅａｂａｓｓ (ＬａｔｅｏｌａｂｒａｘｊａｐｏｎｉｃｕｓＣ＆Ｖ)ｄｉｓｔｒｉｂｕｔｅｓｗｉｄｅｌｙｉｎｔｈｅｃｏａｓｔａｌｗａｔｅｒｓａｌｏｎｇｔｈｅＢｏｈａｉＳｅａ ,ＹｅｌｌｏｗＳｅａ ,ＥａｓｔＣｈｉｎａＳｅａ,ａｎｄＳｏｕｔｈＣｈｉｎａＳｅａ .Ａｓａｃａｒｎｉｖｏｒｏｕｓｆｉｓｈ ,ｉｔｏｃｃｕｐｉｅｓｔｈｅｈｉｇｈｔｒｏｐｈｉｃｌｅｖｅｌｉｎｔｈｅｍａｒｉｎｅｅｃｏｓｙｓｔｅｍａｎｄｈａｓａｄａｐｔｅｄｔｏｖａｒｉｏｕｓｅｎｖｉｒｏｎｍｅｎｔａｌｒ…     

Ice surface-elevation change and velocity of Qingbingtan glacier No.72 in the Tomor region, Tianshan Mountains, central Asia

Glaciers in the Tomor region of Tianshan Mountains preserve vital water resources.However,these glaciers suffer from strong mass losses in the recent years because of global warming.From 2008 to 2009,a large-scale scientific expedition has been carried out in this region.As an individual reference glacier,the tongue area of Qingbingtan glacier No.72 was measured by the high precise Real Time Kinematic-Global Position System (RTK-GPS).In this paper,changes of the tongue area of Qingbingtan glacier No.72 has been studied based on topographic map,remote sensing image and the survey during 2008-2009 field campaign.Results indicated that the ice surface-elevation of the tongue area changed-0.22±0.14 m a-1 from 1964 to 2008.The estimated loss in ice volume was 0.014±0.009 km3,which represented a ～20 % decrease from the 1964 volume and was equivalent to average annual mass balance of-0.20±0.12 m water equivalent for the tongue area during 1964-2008.Terminus retreated by 1852 m,approximately 41 m a-1,with the area reduction of 1.533 km2 (0.034 km2 a-1) from 1964 to 2009.Furthermore,the annual velocity reached to ～70 m a-1.Comparing with the other monitored glaciers in the eastern Tianshan Mountains,Qingbingtan glacier No.72 experienced more intensive in shrinkage,which resulted from the combined effects of climate change and glacier dynamic,providing evidence of the response to climatic warming.     

Standing crop and primary production of benthic microalgae on the tidal flats in Yueqing Bay

The standing stock and primary production of benthic microalgae on tidal flats were measured seasonally at 3 transects (Puqing, Dahengchuang and Puqi) in Yueqing Bay during 2002 2003. The results showed that the integral chlorophyll a (Chl a) concentration in tidal flat mud exhibited a seasonal variation with the order of magnitude: winter (14.0 4.2 mg m-2) > spring (13.0 6.3 mg m-2) > autumn (7.7 5.9 mg m-2) > summer (4.6 3.2 mg m-2). The primary production showed an order of magnitude: spring (270.5 224.9 mgC m-2 d-1)>winter (238.7 225.5 mgC m-2 d-1)>autumn (214.1 56.2 mgC m-2 d-1)>summer (71.6 44.6 mgC m-2 d-1). Both chlorophyll a and primary production showed maximum values in the surface layer of sediment, and decreased rapidly with increasing depth due to sun light limitation. The results of variance analysis indicated that seasonal variation and tidal flat condition affected Chl a greatly, but had no significant effect on primary production. The annual primary production of benthic microalgae on tidal flats in Yueqing Bay was estimated at 16143 tons carbon, which is sufficient to support 1.02×105 tons shellfish production. The environmental factors affecting chlorophyll and primary production on the tidal flats in Yueqing Bay were discussed. By comparing with other bays on China’s coast, it was observed that Yueqing Bay is a region with high benthic microalgae standing crop and primary production, which may be related to the type of its sediment.     

珠江斑鱯的早期胚胎发育观察

观察了珠江斑鳠3批次受精卵的胚胎发育,描述及记录了胚胎发育各期的形态特征及所需时间。斑鳠的成熟卵子呈圆形,黄色,卵子直径为3.1~3.8 mm,吸水后最大卵径为4.0~4.2 mm,受精卵黏性很小。珠江斑鳠胚胎发育与其他硬骨鱼类基本相似,属于盘状卵裂。在水温(27.5±0.5)℃时,受精后约1 h 10 min进入胚盘形成期,受精2 h 15 min后进入卵裂期,受精后7 h 50 min,进入囊胚期,再经约13 h 45 min进入原肠期,受精后21 h15 min,胚孔封闭,当受精39 h 5 min后,心脏开始出现搏动,受精后55 h,仔鱼开始孵出。     

Preparation and charaterization of self-assembled nanoparticles based on linolenic-acid modified chitosan

1 IntroductionHydrophobically modified water-soluble polymers,also known as hydrophobized polymers, are thosemodified by hydrophobic groups such as alkyl,arolkyl, and deoxycholic acid. In water, they canself-aggregate due to their intro- and/or intermolecularhydrophobic interaction. By this process, unique hy-drogel nanoparticles with hydrophobic core and hy-drophilic shell can be prepared, which is a new ap-proach to preparing the monodispersed hydrogelnanoparticles (Whitesides et al., 1991; …     

Identification of ice elevation change of the Shuiguan River No. 4 glacier in the Qilian Mountains,China

GPS measurement,an effective method for surveying glacier surface topography,has been applied in some glaciers for many years.The Shuiguan River No.4 glacier,a small glacier with its area of 1.84 km2 in 1972,located in the east of the Qilian Mountains,China,was selected to study its ice elevation change using GPS measurement in 2007.This study was conducted on the ablation area with GPS-measured area 0.5 km2.The ice elevation change of the glacier was obtained by comparing the DEM obtained by a 1:50 000 topographic map made in 1972 with the DEM by GPS-measured data acquired in 2007.The differences of the two DEMs showed the thinning condition of the glacier was apparent.The mean thinning was 15±8 m with the mean thinning rate of 0.42±0.22 m a-1 for 1972-2007 in the measurement area,which equaled 0.38±0.20 m yr-1 in water equivalent(w.e.).The prominent thinning occurred on the south part of the glacier,which was the area near the glacier terminus with the maximum thinning of 41±8 m.Assuming the thinning value of 15±8 m for the glacier area below 4640 m a.s.l.,the wasting ice mass was calculated to be 6.4±3.2×10-3 km3 for 1972-2007,corresponding to 5.7±2.8×10-3 km3 w.e.,which meant that the montane runoff released by the glacier was at least 5.7±2.8×106 m3 between 1972-2007.     

Impact of microzooplankton and Calanus sinicus (Brodsky, 1962) on phytoplankton in the Yellow Sea during early summer

Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a (Chl-a) levels. The Chl-a growth rates (k) ranged from 0.60–1.67 d⁻¹, while microzooplankton grazed the Chl-a at rates (g) of 0.29–0.62 d^t-1. The addition of C. sinicus enhanced the Chl-a growth rate (Z) by 0.004–0.037 d⁻¹ ind.⁻¹ L. C. sinicus abundance ranged from 84.1–160.9 ind. m⁻³, which occupied 90.7%–99.1% of the copepod (>500 μm) population. The in-situ increase in phytoplankton by C. sinicus community was estimated to be 0.000 4–0.005 9 d⁻¹. These results showed that microzooplankton were the main grazers of phytoplankton, while C. sinicus induced a slight increase in the levels of phytoplankton.     

Isolation of protoplasts from <Emphasis Type="Italic">undaria pinnatifida</Emphasis> by alginate lyase digestion

The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation is enzymatic digestion at 28°C for 2h using alginate lyase at the concentration of 213.36 U (8 mL) every 0.5g fresh thalline with NaCl 50 and at the shaking speed of 150 r min⁻¹ during digestion. The protoplast yield can reach 2.62±0.09 million per 0.5 g fresh leave under the optimum condition. The enzyme activity is inhibited by Ca²⁺ and slightly enhanced by Fe²⁺ and Mn²⁺ at concentrations of 0.05, 0.08 and 0.10 mol L⁻¹.     

A study on the age and growth of Lake Anchovy (Coilia ectenes taihuensis Yuen et Tin) in Taihu Lake

Scales of the Lake Anchovy in Taihu Lake are used as a basis for its age determination. Annual variation of scale edge growth rate (α) indicates that the annulus forms once a year, mainly in April–June. The relationship formula for body length and scale diameter is L=18.658+118.06R, that for body length and weight isW♀=7.588×10⁻⁶ L ^2.8301;W♂=5.584×10⁻⁶ L ^2.8781. The fish before age II have a higher relative growth rate in body length and weight and a higher growth index. Growth is consistent with the growth equation by Von Bertalanffy. The turning point of the body weight growth curve is located between age II and III; the exact position is atW=0.292W _∞. Variation specificity of the growth course can be reflected by the growth rate and its acceleration curves. Time for capture of the fish should preferably be after age II, when they have reached a body length of 170 mm. That is one of the key measures to increase Lake Anchovy production in Taihu Lake.     

The potential of ocean acidification on suppressing larval development in the Pacific oyster Crassostrea gigas and blood cockle Arca inflata Reeve

We evaluated the effect of pH on larval development in larval Pacific oyster （Crassostrea gigas） and blood cockle （Arca inflata Reeve）. The larvae were reared at pH 8.2 （control）, 7.9, 7.6, or 7.3 beginning 30 min or 24 h post fertilization. Exposure to lower pH during early embryonic development inhibited larval shell formation in both species. Compared with the control, larvae took longer to reach the D-veliger stage when reared under pH 7.6 and 7.3. Exposure to lower pH immediately after fertilization resulted in significantly delayed shell formation in the Pacific oyster larvae at pH 7.3 and blood cockle larvae at pH 7.6 and 7.3. However, when exposure was delayed until 24 h post fertilization, shell formation was only inhibited in blood cockle larvae reared at pH 7.3. Thus, the early embryonic stages were more sensitive to acidified conditions. Our results suggest that ocean acidification will have an adverse effect on embryonic development in bivalves. Although the effects appear subtle, they may accumulate and lead to subsequent issues during later larval development.     

Effect of temperature under unfavourable conditions on oxygen uptake of larval herring,Clupea harengus

Oxygen uptake under starvation and short periods of sudden temperature change was measured for larval herring (Clupea harengus L.) reared at average temperature of 7.3, 11 and 12.9°C. Larval stages between first feeding and premetamorphosis were used. For comparison, the routine oxygen uptake (ROU) was also investigated and followed the relationshipQ=0.974+0.174tW ^−0.210, whereQ is in μg/(mg·h),W is dry body weight in mg andt is temperature in °C. The oxygen uptake under starvation (SOU, deprived of food for 24 h) was different from the routine when the larval dry weight was less than 0.6–0.8 mg; it increased with temperature and body weight giving the relationshipQ=1.568+0.110tW ^0.380; if the larval dry weight was more than 0.6–0.8 mg, it reverted to the norm (Q=1.704+0.078tW ^−0.349). The oxygen uptake was tested in short periods (3 h) of sudden temperature changes in six groups: 7.3 to 11, 7.3 to 12.9, 11 to 7.3, 11 to 12.9, 12.9 to 7.3 and 1.29 to 11°C. The oxygen uptake in the 7.3 to 12.9 and 12.9 to 7.3°C groups varied in a way similar to that of the larvae under starvation. The other four groups' oxygen uptake were more or less normal.