长江斑鳜的人工繁殖和苗种培育研究

长江斑鳜(Siniperca scherzeri Steindachner)的催产和受精卵孵化受天气、温度和水温影响较大。长江斑鳜的种质资源锐减,本研究有利于保护长江斑鳜的种质资源,人工繁殖采用人工催产、自然受精和人工孵化的方法。选择团头鲂幼苗为长江斑鳜幼苗的开口饵料,随后以鲤和团头鲂的夏花为主要饵料鱼,辅以从江河中捕获的野杂鱼夏花。在不同水温条件下,效应时间和受精率明显不同。当水温在(20±2)℃时,效应时间约为32h,受精率大于80%;水温低于18℃时,效应时间明显延长,受精率也较低;水温20～24℃时孵化时间约125h,孵化率均超过90%。长江斑鳜幼苗出膜后30～56h开始主动摄食。幼苗全长(L;mm)与日龄(D;d)的线性关系为L=3.244+0.926D,r=0.9940。长江斑鳜的人工繁殖和苗种培育为后续研究及人工养殖提供了资料和参考。     

长江斑鳜的人工繁殖和苗种培育研究

长江斑鳜（Siniperca scherzeri Steindachner）的催产和受精卵孵化受天气、温度和水温影响较大。长江斑鳜的种质资源锐减,本研究有利于保护长江斑鳜的种质资源,人工繁殖采用人工催产、自然受精和人工孵化的方法。选择团头鲂幼苗为长江斑鳜幼苗的开口饵料,随后以鲤和团头鲂的夏花为主要饵料鱼,辅以从江河中捕获的野杂鱼夏花。在不同水温条件下,效应时间和受精率明显不同。当水温在（20±2）℃时,效应时间约为32h,受精率大于80%;水温低于18℃时,效应时间明显延长,受精率也较低;水温20～24℃     

基于水温的鳜与鲢配套催产模式研究

为解决汉江上游流域鳜饵料鱼的配套问题,建立鳜与鲢配套催产模式,分析了水温对鳜和鲢人工繁殖中效应时间、孵化时间、开口时间等的影响,了解鳜和鲢人工繁殖各时间段与水温的相关性。结果表明:鳜孵化时间和开口时间与水温(18~28℃)显著相关,受精卵孵化时间(y)与水温(x)的关系式为y=41 058x~(-2.142 4),R~2=0.995 2,仔鱼开口时间(y)与水温(x)的关系式为y=-0.099 6x~2-5.226 0x+266.02,R2=0.961 4;鲢的效应和孵化总时间(y)与水温(16℃x32℃)的关系式为y=0.051 4x~2-4.924 4x+129.91,R~2=0.978 2;鳜、鲢配套催产时间(y)与水温(x)的关系式为y=-0.151 0x~2-0.301 6x+136.11。研究表明,在水温18~28℃条件下,可根据水温计算出鲢的催产时间,为在鳜人工繁育生产中进行开口饵料鱼的精准配套提供参考。     

昆明裂腹鱼全人工繁殖技术初探

<正>文章对昆明裂腹鱼全人工繁殖过程中的亲鱼催产效应、受精卵孵化等方面的内容进行了研究,结果表明,采用干法和半干法相结合的人工授精,共获得受精卵27.10万粒,受精率53,98%。采用孵化槽孵化,经过170小时~180小时,共孵化鱼苗11,32万尾。催产期间,水温平均16,5℃,效应时间为46小时。孵化水温13℃~18℃,溶氧6,5mg/L时,平均孵化时间176小时,最早174小时。     

瓦氏黄颡鱼人工繁殖技术研究

瓦氏黄颡鱼在池塘生态环境条件下人工培育亲鱼、人工繁殖.产卵季节为每年的5中旬～7月上旬,产卵水温为20～30℃,最佳产卵水温为23～28℃,催产效应时间水温20～30℃为40～52小时.流水水泥池中流水孵化,孵化必须在室内光照500～800Lx条件下进行,孵化出膜时间水温20～30℃为47～70小时.人工繁殖的产卵率、受精率、孵化率均达到90%以上.     

欧洲丁(鱼岁)的人工繁殖技术

欧洲丁(鱼岁)人工繁殖的亲鱼以3～4龄较好,个体要求雌鱼到达400g,雄鱼到达250g以上;催产时间(鹰潭地区)为4月下旬-5月中上旬为好;适宜水温为18～30℃,最适水温为25～28℃,32℃以上时产卵率、受精率和孵化率都较低;催产激素可选择混合激素,剂量为50μg/kg LHRH-A2和5mg/kg DOM合剂;催产方法以两针注射法为好,针距为8～10h;效应时间(水温25℃时)为11～16h;产卵既可自然产卵也可人工授精,孵化一般在网箱中充氧孵化即可,有条件的地方可以实行脱粘后在环道或孵化漕中进行孵化.三年的最高产卵率87%、受精率91%、孵化率93%.     

花提早人工催产及孵化试验

2008年4月16-28日在浙江湖州地区进行了花于水温15℃条件下的人工催产生产性试验。用常规催产剂和方法,催产花亲鱼540尾,其中雌亲鱼355尾、雄亲鱼185尾。试验结果表明:排卵率为91.5%,催产效应时间为29.5 h,群体排卵时间为2.5 h;受精率为98.7%;孵化鱼苗(下塘鱼苗)380万尾。与常规生产水温17～18℃以上催产情况比较,在水温15℃条件下,花也完全可以进行人工催产;除效应时间和孵化时间延长及卵膜难以溶解外,其排卵率、受精率、群体排卵时间和孵化率等均无明显差异。     

欧洲丁的人工繁殖技术

欧洲丁人工繁殖的亲鱼以3~4龄较好,个体要求雌鱼到达400g,雄鱼到达250g以上;催产时间(鹰潭地区)为4月下旬-5月中上旬为好;适宜水温为18~30℃,最适水温为25~28℃,32℃以上时产卵率、受精率和孵化率都较低;催产激素可选择混合激素,剂量为50μg/kg LHRH-A2和5mg/kg DOM合剂;催产方法以两针注射法为好,针距为8~10h;效应时间(水温25℃时)为11~16h;产卵既可自然产卵也可人工授精,孵化一般在网箱中充氧孵化即可,有条件的地方可以实行脱粘后在环道或孵化漕中进行孵化。三年的最高产卵率87%、受精率91%、孵化率93%。     

拉萨裂腹鱼胚胎适宜孵化水温研究

为探索拉萨裂腹鱼胚胎适宜孵化水温，设置5℃、9℃、12℃、14℃、16℃、18℃、20℃、22℃8个温度梯度孵化拉萨裂腹鱼鱼卵，统计各温度下发育速度，鱼卵受精率、孵化率，初孵仔鱼畸形率及形体指标情况。结果表明：拉萨裂腹鱼卵裂期发育最快，到囊胚期、原肠期，器官分化期及出膜期，每个发育时期积累时间逐渐增长，随温度的升高，胚胎发育时间缩短，发育速度加快。胚胎不同发育时期在不同温度条件所积累的时间均呈幂函数关系，温度越高各发育时期所需时间越短。孵化积温随温度升高呈现逐渐降低的趋势。水温在9℃-18℃，鱼卵受精率均较高，超过90%。水温在12-16℃，孵化率均较高，超过95%。水温在9-16℃，鱼苗畸形率均较低，均低于4%。初孵仔鱼全长与孵化温度呈二次多项式函数关系；体高没有显著性差异；卵黄囊体积先升高后降低再升高。因此，适当提高孵化水温能缩短胚胎孵化周期，但水温过高，会影响胚胎孵化率及初孵仔鱼畸形率，影响仔鱼对营养物质的吸收利用以及器官发育分化。综合考虑胚胎孵化周期，孵化率，初孵仔鱼畸形率及形体指标，拉萨裂腹鱼胚胎适宜孵化水温为12~16℃。     

欧洲丁鱥的人工繁殖技术

欧洲丁鱥人工繁殖的亲鱼以3～4龄较好，个体要求雌鱼到达400g，雄鱼到达250g以上；催产时间（鹰潭地区）为4月下旬-5月中上旬为好；适宜水温为18～30℃，最适水温为25～28℃，32℃以上时产卵率、受精率和孵化率都较低；催产激素可选择混合激素，剂量为50μg/kg LHRH—A2和5mg／kg DOM合剂；催产方法以两针注射法为好，针距为8～10h；效应时间（水温25℃时）为11—16h；产卵既可自然产卵也可人工授精，孵化一般在网箱中充氧孵化即可，有条件的地方可以实行脱粘后在环道或孵化漕中进行孵化。三年的最高产卵率87％、受精率91％、孵化率93％。     

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.