多品系南美白对虾苗种的引进与仿生态盐度调节技术

南美白对虾（Litopenaeus vannamei）又称凡纳滨对虾，与斑节对虾、中国对虾并列为世界养殖产量最高的3大优良对虾之一。目前我国淡水、半咸水、高盐度海水养殖南美白对虾技术成熟、养殖面积规模化或初具规模。但是，北方地区正常海水（盐度20～35）的南美白对虾养殖面积规模小、养殖风险大。我国沿海有大量的海水池塘可以进行南美白对虾养殖，海水养殖的南美白对虾口感好，其商品虾销售价位和同规格的中国明对虾不相上下，所以，开展正常海水直接养殖南美白对虾试验非常有必要。     

嘉兴市低盐度海水养虾长势喜人

最近，嘉兴市“中国对虾低盐度海水养殖技术”课题组对协作单位的对虾生产，进行了检查和技术交流。     

珠江口低盐海水双季养虾研究

对珠口低盐海水（盐度24-1）早季养殖中国对虾、晚季养殖草虾技术进行了研究。2种种虾在盐度为26.0的育苗水中可直接移入盐度为10.4的低盐海水中养殖。盐度1.3-10.4范围内的海水中，成活率随盐度升高而提高。珠江口低盐海区一年可养殖两季对虾，早季养中国对虾，晚季养草虾，双季亩产可达280kg以上。     

不同方法处理的海水对中国对虾孵化和早期发育成活的影响

本试验采用经不同方法处理的海水对中国对虾的受精卵进行孵化并对无节幼体进行培育。结果表明，砂滤海水、磁化海水、加入分析纯ＥＤＴＡ的海水、加入工业用ＥＤＴＡ的海水、含聚乙烯塑料薄膜熔出物的海水，这几种海水对中国对虾的孵化率的影响无明显差异。含聚乙烯塑料薄膜熔出物的海水影响无节幼体的活力，并使无节幼体至蚤状幼体的成活率降低。     

黄海北部辽宁沿岸对虾放流水域的IN和IP

１９９６－１９９８年的６－８月对黄海北部辽宁沿岸中国对虾放流水域的ＩＮ、ＩＰ进行了调查,多数站位不同程度地超过一类、二类、三类海水标准,平均值在一类海水标准以上,总的趋势是河口附近和东部偏高。     

当前我国的海水池塘养殖模式及其发展趋势

海水池塘养殖、滩涂贝类养殖及海上筏式养殖是海水养殖业的三大主要养殖方式。我国的海水池塘养殖是从20世纪70年代末中国对虾的大规模养殖开始的．其间经历了对虾低密度养殖→对虾高密度养殖→两茬低密度养殖→多品种生态养殖的发展轨迹。循着这一演变轨迹可以发现，不同的养殖模式对海水池塘的生态效益起着决定性作用，而生态效益又对社会效益和经济效益产生影响，进而影响海水池塘养殖业的发展。本文拟从生态效益角度出发，对目前我国对虾池塘养殖的几种模式作一粗浅的分析、评价。     

中国对虾低盐度养殖试验研究

中国对虾(Penaeus orientalis)俗称明虾，盛产于黄、渤海，其肉嫩味美、生长速度快，养殖期短，经济价值高，畅销于国内外，是海水养殖优良品种。我国开展对虾养殖业已有百余年历史，1958年开始进行人工繁殖技术的研究，1978年全国海水鱼虾养殖现场会议后，对虾养殖发展很快，但养殖一般都在盐度为20‰左右的海水中进行。     

粤西地区几种主要对虾养殖模式的分析

自20世纪80年代以来,广东省对虾养殖主要品种南中国对虾、墨吉对虾、长毛对虾到斑节对虾再到南美白对虾,主要养殖模式由粗放养殖为主发展到粗放、半集约化、集约化几种养殖方式并存,养殖的规模和产量、效益得到了迅猛发展。据广东省海洋与渔业局统计,2002年广东省对虾养殖产量已超过20万吨,其中海水养殖对虾产量近11.8万吨,淡水养殖对虾产量8万多吨。对     

规范养虾管理走健康发展之路

一、我国海水虾类养殖生产发展概况我国的海水虾类养殖业从起步到现在已走过了25个年头。1978年开始组织中国对虾的人工育苗技术攻关，并于1982年获得突破性进展，从此开始了中国海水虾类养殖业的发展历史；1983年后，对虾养殖业迅速在全国沿海地区发展起来，养殖规模不断扩大，养殖产量也急速上升，到1992年仅10年时间，全国的养殖面积发展到208.53万亩，产量达20.7万吨；1993年，因对虾疾病的大面积暴发，养殖产量锐减，当年的产量下降到8.8万吨，1994年继续下降到6.2万吨。为重振我国对虾养殖业，年农业部全国水产1993技术推广总站提出，…     

关手海南岛热带海区试养中国对虾的探讨

中国对虾是一种广盐性、畏酷热的寒温带的经济虾类。它是北方对虾养殖的优良品种，肉质鲜美、生长迅速、抗病力强。近年来，南方的广东、广西、福建等省试养中国对虾相继获得成功。作者于1987年2月24日至5月25日在海南岛万宁县英文海水养殖场进行了中国对虾的南移试养，获得圆满成功，为热带海区试养中国对虾又闯出了一条路子，试验方法值得借鉴。     

Motility of spermatozoa obtained from testes of Japanese pearl oyster <Emphasis Type="Italic">Pinctada fucata martensii</Emphasis>

Effects of NH₃ concentration in sea water and pH of sea water on the motility of spermatozoa obtained from testes were examined in the Japanese pearl oyster Percent motility at 30 s after dilution increased with increasing NH₃ concentration in sea water from 0.75–2.0 mM. When spermatozoa were diluted with sea water containing 0.75 mM NH₃, which is widely used as the insemination fluid in the hatchery of this species, the percent motility increased with time elapsed after dilution, and peaked at 5 min. For spermatozoa diluted with sea water containing 2.0 mM NH₃, the percent motility increased rapidly and peaked at 30 s. The pH of sea water increased with increasing NH₃ concentration from 8.2 (0 mM NH₃) to 9.9 (5.0 mM NH₃). When spermatozoa were diluted with artificial sea water at various pH (buffered without NH₃ at 6.0–10.0), only spermatozoa diluted with artificial sea water of pH 10.0 were motile, and the percent was considerably lower than those in ammonical sea water. These results indicate that sea water containing 2.0 mM NH₃ is a suitable solution for evaluating sperm motility, and that NH₃ and/or ammonium ions may activate sperm motility in this species.     

Changes in structure and fertilizing ability of marine and preshwater fish spermatozoa diluted in media of various salinitiesModification de la structure et du pouvoir fécondant des spermatozoïdes des poissons marins et d'eau douce dilués dans des milieux de différentes salinités

The spermatozoa of various marine teleosts (sea bass, Dicentrarchus labrax; sea bream, Sparus auratus) or fresh water teleosts (trout, Salmo gairdneri; pike, Esox lucius; guppy, Poecilia reticulata) were diluted in media of different salinities. Motility, morphological changes and fertilizing ability were the criteria used in judging the effects of such treatments. The medium best adapted to dilution of sea-fish sperm had a salinity of about 20‰. Sperm motility was increased and prolonged, and fertilization rate was significantly improved (P<0.05) for the sea bass at a $\text{1}\text{1000}$ dilution. For freshwater fish (trout and pike), an extender with about 7‰ salinity increased motility time and fertility ability (P<0.01) as compared to freshwater. After dilution in fresh water the structure of trout spermatozoa was considerably altered (rupture of plasma membrane and mitochondrial swelling). When spermatozoa were diluted in the extender, there were no significant structural changes in trout, but alteration occurred in the mid-piece of the guppy spermatozoon. It is concluded that fresh water or sea water are not the best media for the practice of artificial insemination in freshwater or marine fish. Investigations should be carried out to define the best extender for use in techniques of artificial insemination in fish produced in aquaculture.     

Influence of artificial insemination on the reproductive performance of Farfantepenaeus paulensis in conventional and unisex maturation systems

The application of artificial insemination techniques as a way to overcome the lack of mating of the closed thelycum Farfantepenaeus paulensis under large scale conditions is reported. The performance of artificially inseminated females (49.4±11.6 g) maintained in conventional versus unisex maturation systems was compared. Groups of unilaterally eyestalk-ablated females were artificially inseminated with one compound spermatophore soon after molting. The percentage of fertilized spawns increased from 26% before the use of artificial insemination to 57% afterwards. The reproductive performance of inseminated females held in conventional or unisex maturation systems showed no significant differences. Artificial insemination was considered a practical approach to overcome the lack of mating of F. paulensis under large-scale conditions with acceptable reproductive performance. The results also indicate the possibility of holding females separately from males, which could mean significant improvements in maturation systems through the increase in the stocking density of spawning females.     

Sperm collection, evaluation, preservation and artificial insemination in the dog

The present paper explains the conditions for semen collection in the dog in principal and the technique of semen collection by manual stimulation of the penis in detail. The evaluation of the most important ejaculate parameters is pointed out concerning their dependence of the partially striking variation of the body size of dogs from different breeds. Furthermore some methods of semen preservation and the results of the laboratory examinations are presented. The notes upon artificial insemination contain the time, frequency, interval and technique of semen application. Better conception rates can be obtained by a double than by a single insemination. Using fresh semen an insemination interval of 48 hours has proved favorable whereas with preserved semen the insemination interval should not exceed 24 hours. While freshly ejaculated semen can be applied with good success intravaginally, the intrauterine insemination offers better conditions for conception using liquid or frozen stored semen.     

Method for Determining Apparent Digestibility of Carbohydrate and Protein Sources for Artificial Diets for Juvenile Sea Cucumber,Australostichopus mollis

Effective nursery diets can greatly reduce the cost of producing juvenile sea cucumbers for release to aquaculture or restocking programs. However, methods for systematically testing the bioavailability of artificial diet ingredients for sea cucumbers are poorly developed, and consequently, there has been little research in this field. The current study presents methods developed to test the suitability of common carbohydrate and protein sources for inclusion in artificial diets for juvenile Australostichopus mollis. Apparent digestibility of carbohydrates was moderate and did not exceed 50% for any carbohydrates assayed. Wheat starch and carrageenans showed the highest digestibility amongst carbohydrates. Differences in apparent digestibility were not reflected in growth performance of juvenile A. mollis fed carbohydrate diets; overall growth performance was poor for all diets. Artificial protein sources consistently exhibited higher apparent digestibility, ranging from 75.1% for fish meal to 98.1% for casein. Low‐cost protein sources, like meat meal, show promise for future use in artificial diet formulation. However, delivering high protein content may reduce ingestion rates and thereby lower overall digestive efficiency in juveniles. Results show that artificial carbohydrate sources have some potential as diet constituents for juvenile sea cucumbers but are unsuitable as primary energy sources. Future testing of artificial carbohydrate sources for A. mollis may require predigestion to improve digestibility.     

Diluted rotifer, Brachionus plicatilis (Muller), extract as culture medium stimulates hatching of red sea bream, Pagrus major (Temminck & Schlegel)

Hatching rates and hatching times (50% hatch) of red sea bream, Pagrus major (Temminck & Schlegel), eggs in culture media that were prepared to dilute rotifer Brachionus plicatilis Muller extract at 4000-, 6000-. 8000- and 10 000-fold with artificial sea water (σ₁₅, = 24.0) were investigated. Although differences in hatching rate between the culture media and control artificial sea water were negligible, hatching time was significantly shorter in media at 4000- and 6000-fold dilutions than in media at 8000- and 10 000-fold dilutions and in the control artificial sea water, when the eggs immediately post spawning were incubated. The hatching rates of eggs at three developmental stages, immediately post-spawning, gastrula stage and heart-beat initiation stage, incubated respectively in the medium at 6000-fold dilution and the control, did not differ either, yet the hatching times at each egg stage in the medium were significantly shorter than that in the control. These results suggest that hatching enzyme secretion from the hatching glands is promoted to perceive chemical stimuli in the water-soluble fraction of rotifer extract via the embryo's chemoreceptors, from the heart-beat initiation stage to immediately before hatching, thus shortening the hatching time.     

苏氏圆腹（♂）与南方大口鲶（♀）杂交种的胚胎学观察

在（26＋1）℃水温条件下以苏氏圆腹为父本,南方大口鲶为母本采用干法授精进行杂交,用双筒显微镜对其子一代的胚胎发育过程续跟综观察。结果显示：两者杂交受精率80%,胚胎畸形率72%,孵化率22.4%,整个胚胎发育历时26h35min,其发育过程与其父本、母本基本一致。杂交种既有父本的特征,又有母本的特征,说明绝非单性生殖。     

Spawning of ocean pout (Macrozoarces americanus L.): evidence in favour of internal fertilization of eggs

Sperm physiology, in vivo artificial insemination and spawning of the ocean pout (Macrozoarces americanus L.), a marine bottom fish, were studied. Milt was collected from the reproductive tract of mature males by suction using a catheter. The uncontaminated milt, having a very low sperm concentration, contains highly motile spermatozoa and sperm motility was retained in vitro at 4 °C for at least 24 h in both seminal plasma and ovarian slime collected from the oviduct of pre-spawning females. Instead of activating sperm, dilution in sea water instantly immobilized the spermatozoa of ocean pout. Osmolarity and pH of ocean pout seminal plasma were in the ranges 365–406 mOsM and 7.2–7.5, respectively. A study of the ionic composition of ocean pout seminal plasma demonstrated the presence of various ions including Na⁺, K⁺, Ca²⁺, Mg²⁺, and Cl⁻, with a remarkably lower K⁺ concentration compared to that from other fish species. Since injections of milt containing motile sperm into the ovaries of pre-spawning females, which spawned in the absence of males, yielded fertilized ocean pout eggs, it is concluded that the ocean pout exhibits internal fertilization. The larvae hatched after 3 months of egg incubation in ambient sea water (9–10 °C). With proper timing of in vivo artificial insemination of mature females, fertilized ocean pout eggs can be obtained from fish reared in captivity.     

Nitrite Toxicity to Litopenaeus vannamei in Water Containing Low Concentrations of Sea Salt or Mixed Salts

The uptake, depuration and toxicity of environmental nitrite was characterized in Litopenaeus vannamei exposed in water containing low concentrations of artificial sea salt or mixed salts. In 2 g/L artificial sea salts, nitrite was concentrated in the hemolymph in a dose-dependent and rapid manner (steady-state in about 2 d). When exposed to nitrite in 2 g/L artificial sea salts for 4 d and then moved to a similar environment without added nitrite, complete depuration occurred within a day. Increasing salinity up to 10 g/L decreased uptake of environmental nitrite. Nitrite uptake in environments containing 2 g/L mixed salts (combination of sodium, potassium, calcium and magnesium chlorides) was similar to or lower than rates in 2 g/L artificial sea salt. Toxicity was inversely related to total dissolved salt and chloride concentrations and was highest in 2 g/L artificial sea salt (96-h medial lethal concentration = 8.4 mg/L nitrite-N). Animals that molted during the experiments did not appear to be more susceptible to nitrite than animals that did not molt. The shallow slope of the curve describing the relationship between toxicity and salinity suggests that management of nitrite toxicity in low-salinity shrimp ponds by addition of more salts may not be practical.     

云南盘(绚)人工繁殖及胚胎发育初步观察

采用催产素绒毛膜促性腺激素(human chorionic gonadotrophin,HCG)、促黄体素释放激素A2(luteinizing hormone releasing hormone A2,LHRH-A2)和地欧酮(domperidone,DOM)对性腺发育良好的野生云南盘(绚)(Discogobio yunnanensis)进行人工催产,干法授精.利用体视镜观察早期胚胎发育过程,并详细记录了各发育阶段的形态特征及发育时序.结果显示,云南盘(绚)成熟卵圆形、黄绿色、弱粘性,卵径平均2.1 mm.受精后卵迅速吸水膨胀,卵膜外径平均3.29 mm.在水温17 ～19℃条件下,胚胎发育历时168 h 30 min,胚胎发育过程可划分为受精卵、卵裂、囊胚、原肠胚、神经胚和器官发生6个阶段,共27个分期.初孵仔鱼平均体全长为7.16 mm,平均体质量为0.012 g,初孵仔鱼口凹形成,鳃循环明显,泄殖孔处可见输尿管,残余卵黄囊较大.