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   

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   

Thyroid gland development in Senegalese sole (Solea senegalensis Kaup 1858) during early life stages: A histochemical and immunohistochemical approach     

J.B. Ortiz Delgado  N.M. Ruane  P. Pouso-Ferreira  M.T. Dinis  C. Sarasquete 《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):346-356

A key to success in the culture of marine fish species is the mass production of high quality fry, a process largely dependent on successful first feeding and normal development and growth of fish larvae. In this regard it is important to examine the structural and functional development of the endocrine system (pituitary, thyroid, interrenal glands) during early ontogeny of marine fish. Particularly, the thyroid hormones, thyroxine (T₄) and triiodothyronine (T₃), influence numerous metabolic processes, such as growth, differentiation, metamorphosis, reproduction, respiration, migratory behaviour, central nervous system activity, seasonal adaptation, etc. Therefore the aim of this study was to describe the development of the thyroid gland and the ontogeny appearance of the thyroid hormones in Solea senegalensis larvae by means of histological and immunohistochemical techniques. The first thyroid follicle was present at 4 days-post-hatch (dph) coinciding with first feeding. During metamorphosis (12–20 dph) the follicles increased in both number and size, and by 30 dph presented the same characteristics as that seen in adult fish. Tissue immunostaining of both thyroid hormones decreased during the endogenous larvae development to nearly undetectable levels at the completion of yolk-sac absorption. During larvae exogenous phase, T₃ and T₄ immunostaining was first detected by 6 dph and an increase of specific staining for both hormones was detected between 12 and 20 dph, during metamorphosis phase.  相似文献   

The rearing of common dentex Dentex dentex (L.) During the hatchery and on-growing phases     

G. Koumoundouros  J. Carrillo  P. Divanach  M. Kentouri 《Aquaculture (Amsterdam, Netherlands)》2004,240(1-4):165-173

In the current paper we present the rearing methodology of common dentex (Dentex dentex), a promising candidate for Mediterranean marine aquaculture, from the larval to the on-growing phase. The results are discussed in terms of the efficiency of rearing methodology followed, for the mass production of the species.  相似文献   

帽儿山溪流昆虫纲双翅目大蚊科稚虫分属分类检索     

贾铭宇  刘曼红刑 博等 《安徽农业科学》2014,(22):7459-7462

2011年7月和9月,在东北林业大学帽儿山实验林场溪流利用索伯网和D型网对水生昆虫进行调查和取样,根据外部形态特征对其中的双翅目大蚊科的幼虫进行了物种鉴定,共鉴定出11个属,编写了该区域大蚊科稚虫分属检索表,并对重要检索特征进行了图示。  相似文献