罗氏沼虾养成中白体病防治措施

１．购买虾苗时应检查有无白体病，有病虾苗不要买，同时虾苗入池前应消毒，用０．４×１０－６浓度溴氯海因全池泼洒，３～５天后再用活性微生态制剂按１．５×１０－６浓度全池泼洒，调节水质，抑制有害微生物生长繁殖。２．平时每月用一次溴氯海因０．４×１０－６浓度全池泼洒，每月使用一次虾宁２％按饵料量或虾菌宁５‰按饵料量或虾康宁６‰按饵料量一次，连用３天。３．治疗方法：第一天用溴氯海因０．５×１０－６浓度或二溴海因０．３×１０－６～０．５×１０－６浓度全池泼洒，第二至第六天内服虾宁４％＋虾菌宁５‰…     

有效氯对浮游植物生长的影响

用０．５×１０－６和１．０×１０－６有效氯处理虾池浮游植物，用４．０×１０－６、１００×１０－６和１５０×１０－６有效氯处理叉鞭金藻、球等鞭金藻两个品种（９００２、３０１１）、巴夫藻（３０１２）、塔胞藻和小新月硅藻，结果表明，０．５×１０－６—１．０×１０－６的有效氯对虾池浮游植物产氧有严重抑制，但对叶绿素含量无显著影响；金藻类用１５０×１０－６有效氯处理１．５ｈ仍可存活，但小新月和塔胞藻在有效氯为４．０×１０－６时，短时间即可致死。     

孔雀石绿用于防除桡足类的初步研究

在鲍育苗生产中可以用孔雀石绿的草酸盐来替代敌百虫杀灭培育池中的桡足类。使用 １．０×１０－６的孔雀石绿处理３小时与使用１．５～２．０×１０－６的敌百虫处理１５～２０小时的效果基本一致，且对底栖硅藻和鲍无明显副作用     

EDTA对紫彩血蛤幼虫发育的影响

本文研究了ＥＤＴＡ对紫彩血蛤幼虫生长，存活和变态的影响。结果表明，所有试验的ＥＤＴＡ浓度均能促进幼虫生长，前期３．０×１０＾－６浓度组生长最快，幼虫平均壳长由对照组的２３５．６μｍ增至２３９．７μｍ，后期则以１．０×１０＾－６浓度且生长最快，幼虫平均壳长由对照组的２４７．４μｍ增至２５３．０μｍ；０．５×１０＾－６－５．０×１０＾－６ＥＤＴＡ均能提高幼虫的存活率和变态率，其中以１．０×１０＾－６效     

红螯螯虾对硫酸铜和孔雀石绿耐受性的研究

测定了红螯螯虾虾苗对硫酸铜和孔雀石绿的耐受性，结果表明，２４ｈＬＣ５０分别为６３．８２×１０＾－４％和１３．７８×１０＾－４％；４８ｈＬＣ５０分别为２３．３７×１０＾－４％和４．８４×１０＾－４％；９６ｈＬＣ５０分别为１５．０７×１０＾－４％和２．６５×１０＾－４％；安全浓度分别为０．９４×１０＾－４％和０．１８×１０＾－４％。     

暴发性鱼病菌苗产生免疫力的时间及免疫时效研究

嗜水气单胞菌苗免疫接种试验表明，室温３０℃时，试验鱼注射接种１．８～２．７×１０８个／尾的灭活菌苗，８－１０天后即产生较强的免疫力，注射接种１％一１‰的灭活组织苗０．２－０．３ｍｌ／尾，６－８天后即产生较强的免疫力，两者的保护力均达９２％以上，浸泡相当于１．８×１０６个／ｍｌ的脂多糖粗提物（ＬＰＳ），１０—１２天后产生的保护力可达７０％左右。不同温度的接种试验表明，水温３０℃时接种比１５℃时接种，免疫力的形成早４—７天。大池试验表明，灭活苗苗接种鱼的免疫时效达６个月以上。     

镉对罗氏沼虾组织转氨酶活性及组织结构的影响

对罗氏沼虾（Ｍａｃｒｏｂｒａｃｈｉｕｍｒｏｓｅｎｂｅｒｇｉｉ）成虾六种组织的谷丙转氨酶（ＧＰＴ）和谷草转氨酶（ＧＯＴ）活性正常值作了测定，其中心脏和绿腺的ＧＰＴ和ＧＯＴ活性较高，鳃和肝胰脏次之，卵巢和肌肉较低。不同镉离子浓度（０．３７、０．７４和１．４８×１０－６）对罗氏沼虾的急性中毒试验表明，受水中０．７４和１．４８×１０－６Ｃｄ２＋影响，心脏、鳃和肝胰脏的ＧＰＴ和ＧＯＴ活性显著降低；绿腺的ＧＰＴ和ＧＯＴ活性在０．７４×１０－６组显著升高。组织学观察显示，Ｃｄ２＋中毒引起鳃丝增粗，鳃丝血腔扩大；肝小管严重萎缩，肝细胞解体；绿腺细胞解体，迷路结构消失。     

提高泥蚶附着变态率的生产性试验

１试验条件１．１　设施、设备育苗池１４个，有效面积 ４２０ ｍ２，规格 ５ｍ ×６ ｍ×１．３ ｍ；Ｍ级沙滤池 ２个，规格 ５ ｍ×２ｍ×１．５ ｍ；海边沙滤井 １口；单胞藻培养池 １６个，规格 ３ ｍ×５ ｍ×０．８ ｍ；１２ ｍ３／ｈ罗茨鼓风机１台；蒸发量为２ｔ／ｈ的锅炉１台。１．２　试验材料　饵料为人工培育的等鞭金藻、牟氏角毛藻、青岛大扁藻、异胶藻及海洋酵母。亲蚶系采自浙江乐清人工养殖的３龄泥蚶，规格１６０粒／ｋｇ。２试验方法２．１催产、孵化用沙滤海水冲刷掉亲蚶外壳上的犯及沉垢，然后用５００×１０－６的高…     

草鱼出血病防治

在草鱼养殖过程中，出血病是鱼种培育阶段一种广泛流行、危害性大的病毒性鱼病，发病率高，流行季节长，可造成大批草鱼鱼种的死亡，危害甚大。笔者根据多年实践经验，现将此病的防治方法介绍如下： （１）清除池底过多淤泥，并用２００× １０－６生石灰或２０×１０－６漂白粉（含有效氯３０％）或１０×１０－６漂白精（有效氯６０％）消毒。 （２）鱼种下塘前，用聚乙烯氮戊环酮碘剂 ６０×１０－６药浴２５分钟左右，或用鱼复药３号 ２０～３０×１０－６药浴 ３０～６０分钟。 （３）每万尾鱼种用水花生 ４ ｋｇ，捣烂后拌入 ２５０ｇ…     

三疣梭子蟹虾池养殖技术

我们自１９９６年开始，在虾池中进行了大面积养蟹技术研究，并获得了良好的效果，现报告如下：１材料与方法１．１池塘条件秦楼办事处万平口虾场５个池塘，面积分别为２０亩、２５亩、３０亩，水深１～１．５ ｍ，泥沙底质。水质良好，进、排水方便。１．２清池肥水池塘冬闲时，封池曝晒２０～３０天后清淤。１月下旬进水浸没滩面。使用“敌杀死”０．１～０． ２×１０－６，清除以杂蟹类为主的甲壳类敌害生物。３月上旬，当池水温度达８～１０℃时，使用２０～２５×１０－６的茶籽饼清除害鱼。毒性消失后，注入用６０目筛绢网过滤的海水…     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.     

Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l^–1 TA-N (total ammonia-N) in sea water in 1 m³ tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na^{+, Cl–, Ca2+ or Mg2+} levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).