匙吻鲟苗种规模化培育技术

2010年4月14日至6月1日在湖北宜昌进行了匙吻鲟苗种的规模化培育试验示范。鱼苗培育在室内水槽内进行,放养密度800～1000尾/m2,改善水温、溶氧、流速等养殖条件,适时投喂适口饵料生物,经过15d养殖,获4cm左右的鱼种47.12万尾,成活率95%;鱼种培育在水库坝下池塘进行,放养密度30万～40万尾/hm2,以水温相对稳定、水质优良的水库为养殖水源,及时驯食,转食后日投喂鱼种体重3%～5%的浮性鲟鱼饲料,加强饲养管理,经过30d养殖,获10～12cm鱼种40.47万尾,成活率85.9%。     

新疆地区施氏鲟受精卵及苗种培育技术要点

正2010-2013年,新疆各州的鲟鱼总产量从27吨增加到197吨。由于新疆地区鲟鱼养殖起步较晚,还尚未形成本土地区的鲟鱼繁育群体,因此新疆境内鲟鱼苗种缺乏。此外,新疆地区水文特征独特、鲟鱼养殖技术环节连接不畅,因此其鲟鱼苗种的驯养难度大。笔者于2013-2015年,在新疆地区进行了鲟鱼受精卵自然水体孵化及苗种人工饲料开口驯养的培育试验,经过几年的努力初步获得成功,并对鲟鱼的受     

转食和联合投喂对胭脂鱼仔稚鱼生长和消化能力的影响

为考察转食及联合投喂对胭脂鱼仔稚鱼生长和消化能力的影响,在水温(24±0.5)°C下,用丰年虫、水蚯蚓、微颗粒饲料和螺旋藻作为开口饵料,按照不同配比共设置8个处理组来投喂出膜后10 d(10 dph)的胭脂鱼开口仔鱼,40 dph后有2组(水蚯蚓组和丰年虫组)继续投喂先前的饵料,其余处理组全部进行转食投喂微颗粒饲料。统计养殖各阶段的成活率,并在30,40,45,55和65 dph取材测量全长、体质量及相关酶的活性。结果如下:1在转食前,各个处理组间的存活率无明显差异,均大于90%,40 dph后进行转食的处理组存活率逐渐下降,在实验结束时未进行转食的丰年虫组、水蚯蚓组成活率明显高于相应的转食组(丰年虫/饲料组、水蚯蚓/饲料组)和其他转食组(P0.05);2转食对胭脂鱼仔稚鱼的淀粉酶活性没有太大影响,对丰年虫/饲料组仔稚鱼胰蛋白酶活性影响也不大,但能显著影响水蚯蚓/饲料组仔稚鱼的胰蛋白酶活性(P0.05),对于脂肪酶活性,丰年虫组和水蚯蚓组在40 dph后存在差异,但转食后它们之间的变化趋势接近;3进行联合投喂的2个处理组(丰年虫+饲料+螺旋藻/饲料组、水蚯蚓+饲料+螺旋藻/饲料组)相对未进行联合投喂的处理组(丰年虫+螺旋藻/饲料组、水蚯蚓+螺旋藻/饲料组),在转食前后联合投喂组的体质量和全长均要小于相应的处理组;42个联合投喂组与相应的处理组在转食后,淀粉酶活性都呈现上升趋势,其中2个联合投喂组的淀粉酶活性在转食后均高于相应的处理组(P0.05);2个联合投喂组在转食前后胰蛋白酶和碱性磷酸酶活性整体波动趋势不大,但在转食后5 d脂肪酶活性均呈现先下降后上升的趋势。结果表明:丰年虫、饲料和螺旋藻进行联合投喂胭脂鱼仔鱼,并在40 dph时转食饲料是可行的投喂方案,但饲料投喂比例及添加时间还需进一步研究。     

泥鳅人工繁殖及苗种培育

<正>目前,由于泥鳅规模化人工繁殖和苗种培育技术不够成熟,普遍存在转食阶段存活率偏低的"瓶颈"问题,鳅苗生产成本偏高,养殖的鳅种主要依赖野生捕捞,数量、质量和规格都无法得到保障,严重影响泥鳅养殖业的发展。本试验以鲤鱼配合饲料粉料匀浆上清液和捕捞的浮游动物为开口饲料进行大胆尝试,以探索鳅苗转食阶段低廉的开口饲料,为降低泥鳅苗种培育成本提供基础数据,对规模化泥鳅养殖及其发展具有重要的生产指导意义。一、材料与方法1.材料(1)鳅种来源。供试亲鱼全部由重     

故县水库网箱规模化养殖鲟鱼成鱼试验

在故县水库90个规格为12m×4m×4m的网箱中进行鲟鱼成鱼网箱规模化养殖试验,取得成功。5月中旬投放鲟鱼种,平均规格125g/尾,投放密度41/m2,养殖全程投喂人工配合饲料,10月中旬至12月份完成生产、销售。试验共生产鲟鱼成鱼15.56万尾,105.8吨,平均产量245kg/m2,平均规格0.68kg/尾,成活率88.4%;共投喂饲料166吨,饲料系数1.98,平均利润154.7/m2元,投入产出比为1.29:1。     

史氏鲟人工繁殖及养殖技术（连载）

三、开口期的饲养管理　　(一 )鱼苗开口期的饲料　　卤虫与水蚤对于刚开口的史氏鲟鱼苗来说比较适口，营养也较全面，但投喂时必须达到一定的密度，鲟鱼苗才能充分摄食。当鱼苗得不到足够食物时，会引起相互残食；其次，开口之后的史氏鲟鱼苗生长速度加快，大约经过 4～ 5天左右的培育后，卤虫与水蚤也不再适口，必须改用其他的适口饲料，或用配合饲料强行驯化。水蚯蚓也是较好的鲟鱼开口饲料。但水蚯蚓对刚开口的鲟鱼苗来说，规格稍大些。在投喂前应先将水蚯蚓切碎成小段，用干净水清洗几次至无污液时再投喂。这样持续 4～ 5天后，待鱼苗…     

我国鲟鱼产业现状分析及发展建议(连载二)

三、养殖鲟鱼市场分析近几年来,鲟鱼的价格基本稳定在32~34元/kg,春节前后价格可达36~40元/kg。鲟鱼养殖的成本主要为:饲料、苗种、人工、水电、药品、设施折旧等,养成的成本大约在20~24元/kg左右。投资回报率可达30%~50%,是养殖其它淡水鱼无法比拟的。回报利润如此之高,会不会产生一哄而上的现象呢?可以预见短期内不会发生这种现象,原因在于:一是苗种还不能满足供应;二是水源的限制,养殖鲟鱼的水源要求偏冷水,水温又不能像鲑鳟那样低,水质要清新,以便保证溶氧,最好是流水养殖;三是市场问题,现有的鲟鱼养殖场,已有固定的市场销售渠道,新入围…     

肉食性鱼类食性驯化技术刍议

很多名贵肉食性鱼类已逐渐被开发为养殖新品种 ,但由于其鲜活饲料供应困难 ,大规模的集约化养殖受到限制 ,而采用人工饲料进行投喂能很好地解决这一问题。只是这些名优鱼类进行集约化养殖之前必须进行有效的食性驯化 ,使之由原先摄食鲜活饲料转向摄食人工配合饲料 ,才便于大规模养殖。但在驯化转食过程中 ,若方法不当 ,不仅苗种成活率不能保证 ,还会导致个体大小参差不齐 ,甚至诱发同类相残现象 ,直接影响到生产效益。本文对鱼类的食性驯化技术进行简要分析 ,以期为养殖单位提供有益的借鉴。1驯食环境对食性驯化的影响驯食环境可分为室内水…     

粗唇鮠鱼种人工饲料驯化培育

采用投喂人工配合饲料进行粗唇(鱼危)鱼种培育试验。结果表明:在普通养鱼池塘,放养平均规格1.8-2.2 cm/尾的粗唇(鱼危)苗种,放养密度15-45尾/m~2,经驯化投喂饲料粗蛋白42%的人工配合饲料,经120 d养殖期,粗唇觥平均规格为126-213尾/kg。     

鲟鱼苗种培育阶段气泡病的危害与防治

随着北京地区鲟鱼养殖规模不断扩大,当地对鲟鱼苗种的需求量也越来越大。养殖条件好的养殖户由鲟鱼仔鱼阶段开始进行鲟鱼苗种培育。在鲟鱼苗种培育阶段要经过仔鱼开口摄食和仔鱼转口摄食两个敏感时期。这两个时期是鲟鱼苗种培育成功与否的关键环节。由于鲟鱼仔鱼特殊的生理结构和生活习性,常常会因多种原因导致气泡病的发生,往往造成程度不同的损失,甚至造成大批量死鱼现象。笔者现将鲟鱼苗种培育阶段气泡病防治方面的一些经验和体会总结如下。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

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.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

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.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.