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1.
Wang Yanfeng Chi Liang Liu Qinghua Xiao Yongshuang Ma Daoyuan Xiao Zhizhong Xu Shihong Li Jun 《中国海洋湖沼学报》2019,37(1):350-360
Atlantic salmon reared in recirculating aquaculture system (RAS) may lead to inappropriately high stocking density, because fish live in a limited space. Finding the suitable stocking density of Atlantic salmon reared in RAS is very important for RAS industry. In this paper, the influence of stocking density on growth and some stress related physiological factors were investigated to evaluate the effects of stocking density. The fish were reared for 220 days at five densities (A: 24 kg/m3; B: 21 kg/m3; C: 15 kg/m3; D: 9 kg/ m3 and E: 6 kg/m3 ). The results show that 30 kg/m3 might be the maximum density which RAS can afford in China. The stocking densities under 30 kg/m3 have no effect on mortality of Atlantic salmon reared in RAS. However, the specific growth rate (SGR), final weight and weight gain in the high density group were significantly lower than the lower density groups and middle density groups. Moreover, feed conversion rate (FCR) had a negative correlation with density. Plasma hormone T3 and GH showed significant decrease with the increase of the stocking density of the experiment. Furthermore, thyroid hormone (T3), GH (growth hormone) activities were decreased with stocking density increase. However, plasma cortisol, GOT (glutamic oxalacetic transaminase) and GPT (glutamic pyruvic transaminase) activities were increase with stocking density increase. And the stocking density has no effects on plasma lysozyme of Atlantic salmon reared in RAS. These investigations would also help devise efficient ways to rear adult Atlantic salmon in China and may, in a way, help spread salmon mariculture in China.
相似文献2.
The distribution and chemical properties of colored dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea during December 2011-January 2012 were investigated. The input of freshwater and biological activities had an evident influence on the CDOM levels(characterized by the light absorption coefficient at the wavelength of 355 nm a_(355)) in the study area. The spatial distribution of CDOM levels displayed a gradually decreasing trend from the coastal waters(0.37 m~(-1)) to the open sea(0.18 m~(-1)). The spectral slope ratio(the slope ratio S_R defined as S_(275-295):S_(350-400)) during the cruise was correlated with salinity, and exhibited a large variation from inshore(average of 2.515) to offshore sites(average of 5.327) compared with the distribution of a_(355). The values of S_R were related to CDOM molecular weight(MW). The a_(355), S_R, and chlorophyll a in 37 samples collected from the surface microlayer were significantly correlated with those in the corresponding subsurface water samples, implying a strong exchange action between the microlayer and bulk water. The a_(355) and S_R of CDOM exhibited significant microlayer enrichment, with mean enrichment factors(EFs) of 1.72 and 1.62, respectively. 相似文献
3.
《中国海洋大学学报(英文版)》2020,(5)
In this mini review, we systematized current knowledge about the number of Caligus elongatus on farmed Atlantic salmon in relation to the use of lumpfish as cleaner fish. The review was prompted by reports of an unusually large number of sea lice(C. elongatus) infestation of farmed salmon in northern Norway, Faroese Islands and Iceland and the urgent need to determine if common lumpfish can be used to reduce the number on farmed Atlantic salmon by actively grazing on sea lice. Available data from Norway clearly indicate that lumpfish grazes on C. elongatus, and it is possible to enhance this grazing with the assistances of livefeed conditioning prior to sea pen transfer and selective breeding. Observations from Iceland, Faroese Islands and Scotland also indicate that lumpfish can effectively lower infestations of C. elongatus on salmon. Overall, this mini review expresses that lumpfish can actively lower the number of C. elongatus on farmed Atlantic salmon. 相似文献
4.
The combined effects of feeding rate （0.8%, 1.0%, and 1.2% initial body weight/day）, feeding frequency （two, three, and four times/day） and stocking density （10, 15, and 20 kg/m3） in recirculating aquaculture systems （RAS） on growth performance, digestion and waste generation of Atlantic salmon （Salmo salar L.） were investigated in an 8-week orthogonal experiment （L9（3）3） with a constant daily water renewal at 7.50% of total volume. No mortality occurred during the experimental period. Feed conversion ratio （FCR） varied from 0.90 to 1.13 and specific growth rate （SGR） ranged from 0.48% to 0.69%/day. SGR, thermal growth coefficient （TGC） and FCR were not significantly （P〉0.05） affected by the three factors, while net protein utilization （NPU） was significantly （P〈0.05） affected. Apparent digestibility coefficients （ADC） of dry matter in the present study were in the range 66.12%-73.55%. ADC in protein, lipid and energy were statistically different among all treatments and in the range of 90.07%-93.67%, 81.54%-89.15%, and 67.55%-71.87%, respectively. The proportion of mean total ammonia nitrogen excreted ranged from 1.37% to 1.64% of feed nitrogen at steady state, and the concentration of nitrogenous and phosphorus compounds were differently correlated to the three factors. The results will provide valuable reference data for culture management decisions in the Atlantic salmon farming industry. 相似文献
5.
通过组织切片对虎纹蛙性腺发育过程进行研究，根据其细胞学特征，雌性虎纹蛙的性腺发育过程分为卵原细胞期、初级卵泡期、生长卵泡期和成熟卵泡期；在第一个性周期内，从卵原细胞到成熟卵泡整个发育阶段需要2a。雄性虎纹蛙的生殖细胞成簇排列，性腺发育分为精原细胞、初级精母细胞、次级精母细胞、精子细胞以及精子形成5个阶段；性成熟期为1a。并报道了虎纹蛙的镶嵌型性腺。 相似文献
6.
The effect of light intensity ( 1500 Ix and 5000 Ix) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211 ), Phaeodactylum tricornutum (Bl14, Bl18 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated.The total lipids of B13, Bl14, and B211 grown at 5000 Ix were lower than those grown at 1500 Ix. No evident changes were observed in Bl18, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:l(n- 7) and 20:5(n-3) . Cylindrothecafusiformis had high percentage of 20:4n - 6 (9.2 - 10.9% ) . The total polyunsaturated fatty acid /rl all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis. 相似文献
7.
The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon( Salmo salar L.), the ambient water of unhealthy fish, and the biofilter material in the recirculating aquaculture system(RAS) to understand differences in the intestinal microbiota. The V4–V5 regions of the prokaryotic 16 S r RNA genes in the samples were analyzed by Mi Seq high-throughput sequencing. The fish were adults with no differences in body length or weight. Representative members of the intestinal microbiota were identified. The intestinal microbiota of the healthy fishincluded Proteobacteria(44.33%), Actinobacteria(17.89%), Bacteroidetes(15.25%), and Firmicutes(9.11%), among which the families Micrococcaceae and Oxalobacteraceae and genera S phingomonas, Streptomyces, Pedobacter, Janthinobacterium, Burkholderia, and Balneimonas were most abundant. Proteobacteria(70.46%), Bacteroidetes(7.59%), and Firmicutes(7.55%) dominated the microbiota of unhealthy fish, and Chloroflexi(2.71%), and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented. Overall, the intestinal hindgut microbiota differed between healthy and unhealthy fish. This study off ers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota. 相似文献
8.
Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese Iongliners during 2003, 2004 and 2005, which is a part of Chinese Tuna Fishery Scientific Observer Program (CTFSOP). The reproductive biology has been investigated. A total of 1023 samples are collected including 417 ovaries and 606 testes. Spawning activities of yellowfin tuna have been studied for both male and female from January to June. The data showed that the average monthly sex ratio is 0.59, and the minimum length at sexual maturity is 101 cm for female and 110 cm for male respectively. Length at 50% sexual maturity is esti- mated at 113.77 cm for female and 120.20 cm for male, whereas maturation rate is 0.066 cm-1 for female and 0.091 cm-1 for male. Sex ratio by length class indicates that the proportion of male is higher than female's along with size increasing; for instance, in the group of the body length longer than 145 cm, some females have their body length from 145 to 160 cm and males have their body length at 160 cm and even longer. Statistically, yellowfin tuna has a significant seasonal reproduction. 相似文献
9.
When cultured under certain environmental conditions (25°C, light intensity 80 μmol/m2·s, LD 12/12, in enriched seawater medium with 7×10−4 mol/L NO3−N, 1.56×10−4 mol/L, PO4−P and supplements of other elements like Mn, Fe, I, etc.), male and female gametophytes ofU. pinnatifida kept growing vegetatively and propagated fast at average daily fresh weight increase rate of about 20%. The empirical formulaG
m=G
o·3m was established to estimate the output of vegetative gametophytes. Vigorous vegetative gametophyte cells began to form reproductive
structures (oogonium and spermatangium, when the temperature was lower than 25°C and other environmental factors were kept
optimal. The sufficient supply of gametophyte cells provided enough seeds for raisingUndaria sporelings on production scale. Controlled cross-breeding experiments using selected male and female gametophyte clones which
increase their cell number by mitosis instead of meiosis were also carried out in vitro. Juvenile sporophytes from the cross-breeding
had almost the same length and width increase rates as those of the control. The fact that vegetative gametophytes can be
purposely selected, propagated quickly, cross-bred, with the resulting sporophytes having almost the same characteristics
leads to a new way to select desiredUndaria strains for long time use without losing the desired economic characteristics.
Contribution No. 2696 from the Institute of Oceanology, Chinese Academy of Sciences.
Supported by National Natural Science Foundation of China. 相似文献
10.
The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few species have been studied under well-controlled laboratory conditions. In this work, the effects of temperature and photoperiod on gonad development and spawning of Cephalothrix hongkongiensis were observed by rearing worms under different temperatures and photoperiods. Worms reared at 4℃ and 6℃ showed no growth or gonadal development, and all died within 109 days. At 8℃ and 12℃, gonads could be seen from 90 days to the termination of the 360-day experiment, but no spawning was observed. Worms maintained at 16, 24, and 28℃ showed both gonadal development and spawning, and matured faster at higher temperatures. Under a fixed temperature(16℃), photoperiod did not have any significant impact on maturation and spawning. It is likely that temperature plays a major role in regulating the maturation and reproductive cycle of C. hongkongiensis. 相似文献
11.
Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese longliners during 2003, 2004 and
2005, which is a part of Chinese Tuna Fishery Scientific Observer Program (CTFSOP). The reproductive biology has been investigated.
A total of 1 023 samples are collected including 417 ovaries and 606 testes. Spawning activities of yellowfin tuna have been
studied for both male and female from January to June. The data showed that the average monthly sex ratio is 0.59, and the
minimum length at sexual maturity is 101 cm for female and 110 cm for male respectively. Length at 50% sexual maturity is
estimated at 113.77 cm for female and 120.20 cm for male, whereas maturation rate is 0.066 cm−1 for female and 0.091 cm−1 for male. Sex ratio by length class indicates that the proportion of male is higher than female’s along with size increasing;
for instance, in the group of the body length longer than 145 cm, some females have their body length from 145 to 160 cm and
males have their body length at 160 cm and even longer. Statistically, yellowfin tuna has a significant seasonal reproduction. 相似文献
12.
The effects of wavelength-specific visible light,white light,and ultraviolet-B(UV-B,280-31 5 nm)on selected behaviors,grazing rate,spawning rate,and hatching rate of the marine copepod Calanus sinicus collected from the Yellow Sea were studied.Calanus s inicus placed in a partitioned experimental sy stem responded positively phototaxis to blue-cyan and yellow light but negatively to orange light and UVB.No obvious dodge activity was found among C.s inicus irradiated with0.005 mW/cm~2 UV-B.Under0.20,0.30 and 0.50 mW/cm~2 UV-B radiation,the lethal half times of individuals were 30.47,2.86,and1.96 h,respectively.Grazing of C.sinicus was restrained at0.10 mW/cm~2 UV-B,whereas yellow-red light stimulated grazing.Egg production rate was highest at a white-light intensity of 1.58 mW/cm~2,with an average rate of 10.04 eggs/(female d).These results are consistent with the observed phenomenon that C.sinicus in the Yellow Sea mostly spa.wn near dawn.Our results indicate that light intensity and spectrum are important factors affecting the diel vertical migration of C.sinicus under natural conditions in the Yellow Sea. 相似文献
13.
对雌雄短吻新银鱼肌肉营养成分进行了比较分析。结果表明:雌性短吻新银鱼肌肉鲜样中粗蛋白显著低于雄性(P<0.05),粗灰分极显著低于雄性(P<0.01),而雌雄水分和粗脂肪含量无显著差异(P>0.05);短吻新银鱼肌肉样品中均测出18种氨基酸,但在含量上雄性短吻新银鱼绝大多数氨基酸均显著高于雌性(P<0.05)。其中雌雄短吻新银鱼肌肉干样中鲜味氨基酸(DAA)总量分别为26.43%、30.47%,占氨基酸总量的分别35.23%、35.83%。以氨基酸评分(Amino acid score)进行评价,雌雄短吻新银鱼的第一限制性氨基酸均为缬氨酸,第二限制性氨基酸为色氨酸,而以CS进行评价时,雌雄短吻新银鱼的第一限制性氨基酸均为色氨酸,第二限制性氨基酸为缬氨酸。雌雄短尾新银鱼的必需氨基酸指数(Essential acid score index)分别为89.51、93.13,构成比例符合FAO/WHO规定的优质蛋白质标准。雌短吻新银鱼鲜味氨基酸总量、必需氨基酸含量,氨基酸总量、DHA的比例显著低于雄性短吻新银鱼(P<0.05)。表明雄性短吻新银鱼的营养价值较雌性银鱼丰富,具有较高的食用价值和保健作用。 相似文献
14.
Sori formation inLaminaria japonica was studied from the ecological and physiological point of view. Cutting through the medulla ofLaminaria japonica improved the formation of sori. Sori formation under different water temperature, photoperiod, and light intensity was investigated
and total nitrogen and reducible sugar content determined. The result showed that sori ofL. japonica can be formed in 1–22°C water in Dalian. No sori were found in water over 23°C. High temperature inhibits the formation of
sori, but low temperature has no effect. Apparently, light intensity affects the formation of sori, but photoperiod does not.
In shallow waterL. japonica grows slower but stores dry material faster and forms sori rapidly. In deeper water it grows faster in length but stores
dry material slower and the sori formation is slow. Analysis of dry material shows that during sori formation the water content
decreases but total nitrogen and total reducible sugar increase. Only when the storage of sugar reaches a certain level can
sori begin to form. Cutting through the medulla interrupts the passage of nutrients to the growth area. Storage of carbohydrates
and nitrogen is the main factor affecting sori formation. 相似文献
15.
Evaluation of spectral scale effects in estimation of vegetation leaf area index using spectral indices methods 总被引：1，自引：0，他引：1
Spectral index methodology has been widely used in Leaf Area Index (LAI) retrieval at different spatial scales. There are differences in the spectral response of different remote sensors and thus spectral scale effect generated during the use of spectral indices to retrieve LAI. In this study, PROSPECT, leaf optical properties model and Scattering by Arbitrarily Inclined Layers (SAIL) model, were used to simulate canopy spectral reflectance with a bandwidth of 5 nm and a Gaussian spectral response function was employed to simulate the spectral data at six bandwidths ranging from 10 to 35 nm. Additionally, for bandwidths from 5 to 35 nm, the correlation between the spectral index and LAI, and the sensitivities of the spectral index to changes in LAI and bandwidth were analyzed. Finally, the reflectance data at six bandwidths ranging from 40 to 65 nm were used to verify the spectral scale effect generated during the use of the spectral index to retrieve LAI. Results indicate that Vegetation Index of the Universal Pattern Decomposition (VIUPD) had the highest accuracy during LAI retrieval. Followed by Normalized Difference Vegetation Index (NDVI), Modified Simple Ratio Indices (MSRI) and Triangle Vegetation Index (TVI), although the coefficient of determination R 2 was higher than 0.96, the retrieved LAI values were less than the actual value and thus lacked validity. Other spectral indices were significantly affected by the spectral scale effect with poor retrieval results. In this study, VIUPD, which exhibited a relatively good correlation and sensitivity to LAI, was less affected by the spectral scale effect and had a relatively good retrieval capability. This conclusion supports a purported feature independent of the sensor of this model and also confirms the great potential of VIUPD for retrieval of physicochemical parameters of vegetation using multi-source remote sensing data. 相似文献
16.
采用Wright’s-Geimsa混合染料对三疣梭子蟹、锈斑蟳和锯缘青蟹的血淋巴细胞进行染色,光镜下对这三种海水蟹的血淋巴细胞进行了观察和比较。根据血淋巴细胞的核质比、细胞整体着色特点、细胞质中颗粒的存在与否、颗粒的数量和分布等,三种海水蟹的血淋巴细胞均可分为颗粒细胞、半颗粒细胞和透明细胞三种主要类型,三种蟹的同类血淋巴细胞在染色形态上稍有差别。三种蟹的颗粒细胞大小差异较大,而半颗粒细胞和透明细胞大小相近。三种蟹的血淋巴细胞均以半颗粒细胞为主,透明细胞在血淋巴细胞中所占比例最小。三种蟹的血淋巴细胞密度均存在明显的雌雄差异,锈斑蟳和锯缘青蟹血淋巴细胞分类计数也存在明显的雌雄差异。 相似文献
17.
北极城镇空间信息对于研究北极,认识北极,利用北极都有重要意义。本文以北极圈内的城市特罗姆瑟为例,使用Landsat影像、DMSP/OLS夜间灯光、ASTER-GDEM2数据,通过特征提取得到属于光谱特征、纹理特征、夜间灯光特征、地形特征等18个特征,识别最优特征组合后基于AdaBoost算法提取1990、2004、2016年研究区的城镇用地,并将提取结果与最大似然法进行了对比,在此基础上进行了扩张分析。研究结果表明：引入地形与夜间灯光特征都可以在光谱纹理特征的基础上提高提取精度。基于光谱与纹理特征得到的总体精度与kappa值分别为86.20%和0.68;加入地形特征后精度分别提高2.70%（OA）和6.21%（kappa）;加入夜间灯光特征后精度分别提高2.10%和0.50;加入地形与夜间灯光特征精度分别提高3.70%和8.55%,因此光谱、纹理、地形与夜间灯光的组合是最优特征组合。通过最优特征组合进行AdaBoost城镇提取,比最大似然法对城镇的两分类总体精度高10%左右、kappa值高20%左右。计算结果显示,研究区城镇扩张强度为5.5×10-4左右,属于缓慢扩张;扩张的平均动态度水平为0.018,是全球水平（0.0325）的一半左右;2004-2016年的动态度水平低于1990-2004年的动态度水平,说明研究区目前由高速发展期向平稳发展期过渡。 相似文献
18.
【目的】建立可用于大规模培养的户外开放式微藻培养体系。【方法】设计一种微藻平面开放浅层培养(Flat,open and shallow,FOS,简称浮法)体系,以小球藻(Chlorella sorokiniana)为模式藻种,探讨温度、光照、pH值和培养基营养成分等因素在该培养体系中对小球藻生长的影响,开展900 L体系的户外培养试验。【结果】浮法体系主要由塑料袋和垫板组成,在该培养体系中的小球藻在20~40℃范围内均可生长,最适生长温度为30~35℃。小球藻生长有明显的照度依赖性,无光时几不生长,随着照度升高,生长速度加快,在较高的照度下表现有光饱和现象。以TAP为基础培养基,在碳源或氮源缺乏时小球藻几不生长。pH 7.5左右有利于小球藻生长。900 L体系的户外培养试验的生物量(干物质得率)为0.15 g/(L·d)。【结论】在此新型户外平面开放浅层微藻培养体系中,温度、照度、pH值及营养成分等对小球藻的生长均有不同程度的影响。该体系有成本低、操作简便、容易控制、自然资源利用率高等特点,有大面积推广潜力。 相似文献
19.
During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60–120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S. japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia. 相似文献
20.
李正炎 《中国海洋湖沼学报》2005,23(2):163-168
Imposex, specifically caused by TBT pollution, refers to the superimposition of male sexual characteristics in gastropod females. Seasonal variation of imposex intensity in Thais clavigera from both slightly and severely contaminated sites in Hong Kong waters was studied from 1988 to 1999. The male penis length showed significant difference between both sites and seasons. It was shortest during late autumn and early winter (October to December) and longest during spring and early summer (February to June). Female penis length also showed significant difference between sites. It did not change seasonally, however. The RPS (Relative Penis Size) index was the highest during autumn and early winter, and the lowest during spring and early summer. The VDS (Vas Deferens Sequence) index remained stable throughout the sampling period. This study showed that VDS index is a better indicator when we compare relative intensity of imposex. The comparison can only be meaningful provided the samples from different locations are taken during the same season. 相似文献