Culture of Eriocheir sinensis Larvae in Ponds in Greenhouse     

《农业科学与技术》2016,(3)

A total of 15 pools were selected from a greenhouse, and they were randomly and evenly divided into three groups. In each group, one stocking density of Eriocheir sinensis was arranged. The results showed that after 45-d culture, the crab number per kilogram reached about 300 with survival rate of about 20%; the initial stocking density had significantly effect on the body size of E. sinensis on sel , instead on the survival rate of E. sinensis larvae. Therefore, it is feasible to conduct the culture of E. sinensis larvae in a pool in greenhouse.  相似文献   

Rearing performance of Clarias batrachus larvae: Effect of age at stocking on growth and survival during fingerling production     

S.K. Sahoo  S.S. Giri  S. Chandra 《Aquaculture (Amsterdam, Netherlands)》2008,280(1-4):158-160

An experiment was conducted to evaluate the rearing performance of different larval stages for optimum growth and survival during fingerling production of Clarias batrachus with an aim to reduce the rearing time of the catfish larvae in a hatchery system. The larvae were reared for 5, 10 and 15 days before stocking them in the nursery tanks. No significant (P < 0.05) difference could be found in length increment at the end of first week of rearing. But the total length was reduced during rest three weeks in five days old larvae compared to that of other two higher age groups. In 5 days old larvae the reduced weight (P < 0.05) was observed during the entire rearing period. However, the specific growth rate (SGR) did not vary among the groups. The survival rate as well as total biomass was decreased while stocking five days old larvae for rearing, compared to that of other two age groups.  相似文献   

The effect ofDendrolimus superans breakout on growth of trees     

Ma Dongmei  Qin Shili  Song Chunbin  Lu Kuicheng  Zhang Baohong  Liu Jiming 《林业研究》1998,9(4):269-272

The effect ofDendrolimus superans on growth of trees was investigated after the breakout in Shibazhan forest area in 1990. Stem analysis was conducted for determining the tree increment loss. The result showed that the current annual increment for extreme heavily damaged, heavily damaged, moderately damaged and lightly damaged stands is 14%, 39.8%, 64% and 82% of that of the control forest respectively. (Responsible Editor: Chai Ruihai)  相似文献   

Influence of food quality and quantity on the growth and development of Crassostrea gigas larvae: a modeling approach     

Eric N. Powell  Eleanor A. Bochenek  John M. Klinck  Eileen E. Hofmann 《Aquaculture (Amsterdam, Netherlands)》2002,210(1-4):89-117

A biochemically based model was developed to simulate the growth, development and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model is unique in that it (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate and ash content; (2) tracks weight separately from length to follow larval condition index and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for larval filtration, ingestion and respiration that determine growth rate and processes controlling larval mortality and metamorphosis. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food.

The simulations show that genetically determined variations in growth efficiency produce significant changes in larval survival and success at metamorphosis. Larvae with low growth efficiency are successful under a much narrower range of culture conditions than larvae with high growth efficiency. The impact of low growth efficiency is primarily controlled by the ability of larvae to store lipid for metamorphosis. Culture conditions that provide increased dietary lipid counterweigh low growth efficiency. Changes in food quantity and quality had little effect on size at metamorphosis. On the other hand, larval life span and success rate at metamorphosis varied over a wide range depending upon the conditions of the simulation. Food quality and food availability both influence larval life span and, hence, larval survival. As ingestion rate decreases, larval life span increases and cohort survival declines. Increased lipid or decreased protein in the diet improves cohort survival. Changes in carbohydrate content are less influential. If cohort success is significantly affected by mortality during larval life rather than success at metamorphosis, the influence of food quality becomes more complex. The range of food compositions yielding high survival is restricted by a balance between improved success at metamorphosis obtained by increased lipid storage and the shortening of larval life span as a result of more rapid growth, a function of protein availability. These simulations illustrate the strength and utility of numerical models for evaluating and designing hatchery protocols for optimizing yield of C. gigas larvae.  相似文献   

A system for model-based biomass estimation of larvae in intensive cod larvicultures     

Morten?O.?AlverEmail author  Jo?A.?Alfredsen  Gunvor??ie 《Aquaculture International》2005,13(6):519-541

High and unpredictable mortality rates are observed in the larval rearing of cod (Gadus morhua). As a means of addressing this problem, we present a model-based estimator system which can be used to indirectly measure the larval density through monitoring the live food dynamics and larval growth. The estimator has been evaluated in a conceptual context using a preliminary model formulation, and the observability of the process has been investigated. It was found that the two parameters, live food dynamics and larval growth, contain enough information for the larval density to be estimated under noisy conditions, given the correct model. When the system is applied practically, the estimation error will depend on the measurement and model accuracy; this is especially true with respect to the predictability of the feed intake rate of the fish.  相似文献   

温度和盐度对花鲈胚胎及前期仔鱼发育影响的初步报告   总被引：30，自引：0，他引：30  

王永新  陈建国 《水产科技情报》1995,22(2):54-57

花鲈（Ｌａｔｅｏｌａｂｒａｘ ｊａｐｏｎｉｃｕｓ）胚胎发育的适宜温度为１０～２２℃，１０℃组中的畸形率偏高，因此最适宜温度为１３～２２℃。短时期的７℃低温对胚胎发育没有影响；前期仔鱼的适温范围与胚胎的适温范围基本一致。胚胎发育的适宜 盐度为１９‰～２８‰，以２２‰～２５‰为最佳；仔鱼对盐度的要求与胚胎期近似。以低盐度和高盐 度相比较，４日龄以后，低盐度似有利于仔鱼存活。  相似文献   

多鳞鱚早期发育形态   总被引：2，自引：0，他引：2  

万瑞景 《海洋水产研究》1996,(1)

多鳞的受精卵在水温２０．５～２０．８℃，经２ｈ３００ｍｉｎ发育到多细胞期；４ｈ为囊胚期；１８ｈ３０ｍｉｎ原口关闭、胚体形成；３６ｈ３０ｍｉｎ仔鱼孵化。初孵仔鱼全长１．５６～１．６４ｍｍ，油球在印黄囊后下方。孵化后２１～３１ｈ，肛门开口于体外，胸结芽形成，尾鳍膜出现弹性丝。５０ｈ仔鱼全长２．３４ｍｍ，口完全张开，口裂０．１０ｍｍ。７２ｈ仔鱼全长２．５１ｍｍ，卵黄完全被吸收，油球吸收殆尽。口、咽、胃和肠相通。胸鳍条４根，尾部弹性丝２０余根。９８ｈ仔鱼全长２．６５ｍｍ，印黄、油球完全被吸收，口裂０．２２ｍｍ。  相似文献   

酸碱度和干露对墨西哥湾扇贝幼虫和稚贝的影响   总被引：2，自引：0，他引：2  

陆彤霞  龙仲杰  陈清建 《水产科学》2003,22(2):6-8

为探讨酸碱度和干露对墨西哥湾扇贝不同发育阶段的影响,2000年4月和2001年4月在浙江省玉环县抛西水产育苗场用实验生态的方法研究了酸碱度和干露对墨西哥湾扇贝浮游幼虫和稚贝生长和存活的影响。结果表明:pH值7～8存活率最高,生长最好。稚贝的耐干露能力低下。  相似文献   

Acute Toxicity of Synthetic Pyrethroid Cypermethrin on the Common Carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> L.) Embryos and Larvae     

Rahmi?Ayd?nEmail author  Kenan?K?prücü  Mustafa?D?rücü  Sibel??im?ek?K?prücü  Murat?Pala 《Aquaculture International》2005,13(5):451-458

In this study, the toxic effects on the embryos and larvae of the common carp were used as a model to investigate the synthetic pyrethroid pesticide, cypermethrin, which contaminates aquatic ecosystems. Data obtained from the cypermethrin acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The control and eight test experiments were repeated five times. The number of dead embryos significantly increased in response to cypermethrin concentrations 0.0001, 0.001, 0.01, 0.1, 1, 2, 4 and 8 μg l⁻¹ (p<0.05 for each case). The 48 h LC₅₀ value (with 95% confidence limits) of cypermethrin for common carp embryos was estimated at 0.909 (0.256–5.074) μg l⁻¹. Dose–response decreases in hatching success were recorded as 87.4, 85.0, 80.2, 71.4, 56.3, 48.6, 38.8 and 23.5%, respectively. The lowest concentration of cypermethrin (0.0001 μg l⁻¹) produced a significant increase in the number of dead larvae compared to the control group (p<0.05). The number of dead larvae significantly increased with increasing cypermethrin concentrations exposed for 1–96 h (p<0.05). The highest concentration (8 μg l⁻¹) showed the highest larvae mortality. The 96 h LC₅₀ value (with 95% confidence limits) of cypermethrin for common carp larvae was estimated at 0.809 (0.530–1.308) μg l⁻¹. The results of the study suggest that low levels of cypermethrin in the aquatic environment may have a significant effect on the reproduction and development of carp.  相似文献   

Treatment of the early life stages of scallop (Pecten maximus) with antimicrobial agents; searching for an alternative to chloramphenicol     

Lise Torkildsen  Rosie Coyne  Ole Bent Samuelsen  Thorolf Magnesen  Øivind Bergh 《Aquaculture International》2002,10(5):399-409

High mortality rates are often observed in rearing the early stages of the great scallop, Pecten maximus. The addition of antibacterial agents has been necessary to improve larval survival. However, as one antibacterial agent, chloramphenicol, is banned in Norway and Europe the aim of this study is to investigate alternative antibacterial agents. The therapeutic agents investigated in this study were florfenicol, oxytetracycline, oxolinic acid, neomycin and Pyceze. The mean minimum inhibitory concentration (MIC) values were determined for oxytetracycline, oxolinic acid and Pyceze against bacteria isolated from scallop larvae. Two types of treatment regime were investigated on an intermediate scale (20 L). One regime involved continuous exposure of scallop larvae to the therapeutic agent while the other involved a short exposure lasting two hours. All intermediate scale treatments were performed in parallel to large-scale production (800 L) treatment with chloramphenicol. Of the therapeutants investigated, oxolinic acid was the most effective, although only at high concentrations. The short exposure of two hours was ineffective for all therapeutics.  相似文献