花[鱼骨]胚胎和仔鱼发育的初步研究

本文报道了采用胸鳍基部一次注射LRHA-A2和DOM催产花亲鱼,采用平铺、悬挂、底层漂浮棕榈皮鱼巢三种接卵方式及流水条件下遮光、不遮光,静水条件下遮光、不遮光四种不同孵化方式的试验结果。在水温18.2-19.8℃条件下,花胚胎发育需140 h破膜。观察了胚后组织、器官、系统生理发育过程,该鱼在破膜后52h进入混合营养期。不可逆点（PNR）为仔鱼破膜后第8d。     

黄河上游极边扁咽齿鱼人工繁殖试验

采取干导法进行人工授精,2年累计孵化极边扁咽齿鱼受精卵14万粒,平均受精率87.5%,发眼率77.5%,上浮率72%.在孵化水温10～14 ℃条件下,从受精到发眼平均积温为2012.5 ℃·h;从发眼到破膜平均积温为575 ℃·h;从破膜到卵黄囊吸收完平均积温为3734 ℃·h;鱼苗全部发育平均积温为6321.5 ℃·h.     

花(鱼骨)的人工繁殖与苗种培育试验

试验结果表明,催产花亲鱼9组,雌鱼平均体质量105 g,催产率82%;获受精卵1.2万粒,受精率85%;获水花1.0万尾,孵化率84%。水花鱼苗于池塘中养殖120 d,收获鱼种7200尾,平均体长12.45 cm,平均体质量20.47 g,养殖成活率72%。平均水温21.5℃,花受精卵120 h破膜;破膜后第15 d,臀鳍出现,平均全长12.5 mm,外部形态发育完善。     

唇(鱼骨)(♀)×花(鱼骨)(♂)杂交育种初步研究

研究分析了唇(鱼骨)(♀)×花(鱼骨)(♂)杂交育种的特点和可行性.结果表明:2008-2011年,共计获得约164万粒受精卵,杂交F1鱼苗111.7万尾.在水温18～26℃条件下,唇(鱼骨)(♀)×花(鱼骨)(♂)的催产率、受精率和孵化率可达到85.5％～89.2％、80.6％～81.2％和80％～85.6％.在水温(20±1)℃条件下,杂交F1受精卵在受精后94 h 10 min,仔鱼开始出膜.初孵仔鱼全长5.75 ～ 6.83 mm.杂交F1成鱼的体色和体型与母本比较相近.唇(鱼骨)(♀)×花(鱼骨)(♂)的杂交育种是可行的.     

眼斑花鲈的人工繁殖及苗种培育技术

根据眼斑花鲈的繁殖生态特征选择性腺发育比较成熟的亲鱼进行产前强化培育,通过人工或自然方式对亲鱼进行配对,在适宜的水温下,受精卵经60～72 h孵化出膜,初孵仔鱼72 h后卵黄囊消失,开口摄食.鱼苗开口饵料以卤虫无节幼体为主,经过1个月左右的培育,苗种的体长可达2 cm左右.     

花[鱼骨]的人工繁殖与苗种培育试验

试验结果表明，催产花[鱼骨]亲鱼9组，雌鱼平均体质量105g，催产率82％；获受精卵1．2万粒，受精率85％；获水花1．0万尾，孵化率84％。水花鱼苗于池塘中养殖120d，收获鱼种7200尾，平均体长12．45cm，平均体质量20．47g，养殖成活率72％。平均水温21．5℃，花[鱼骨]受精卵120h破膜；破膜后第15d，臀鳍出现，平均全长12．5mm，外部形态发育完善。     

黑龙江流域江鳕的胚胎发育

采用固定后剥离卵膜后拍照的方法,在平均水温1.61℃下系统观察了黑龙江流域江鳕（Lota Iota Linnaeus）的胚胎发育。根据发育特征,将江鳕整个胚胎发育过程分六个大的发育阶段。黑龙江流域江鳕受精卵为淡黄色,近似圆球形,具有微粘性,比重略大于水,内部紧靠卵膜分布大量的脂肪滴,吸水膨胀后卵径为1.01±0.11mm,在平均水温为1.61℃水温条件下受精卵至破膜共历时1746h,需4106.98℃.h,进一步细分为21个发育时期。将黑龙江流域江鳕和新疆额尔齐斯河流域江鳕的胚胎发育过程进行了对比分析,为黑龙江流域江鳕的人工养殖和自然资源的复壮提供了基础资料。     

利用叶绿素荧光技术揭示人工培育的铜藻幼苗对胁迫温度、光照和盐度的反应

2008年以全人工条件下培育的铜藻Sargassum horneri幼苗为材料,利用叶绿素荧光测定仪,通过测量经过暗适应后最大叶绿素荧光量子产量变化(Fv/Fm),研究了不同温度、光照强度和盐度条件下铜藻幼苗光合作用的变化.数据表明,幼苗存活温度上限为28℃,最适生长温度为22～24℃.在消减的太阳光照射下,受胁迫的幼苗即时荧光产量(Fm′)最低降到0.4.随着光强降低,Fm′可恢复到初始值0.73;在室外太阳光直射下,胁迫幼苗的Fm′最低降到0.11,24 h恢复后为0.5,叶片有萎焉现象.结果表明,铜藻幼苗易受高温、强光胁迫,最好进行遮光培育.9～60盐度的胁迫6 h以内对幼苗的Fv/Fm影响不明显,淡水在1 h内对铜藻的Fv/Fm无影响,可以将苗帘直接浸泡在淡水中以清除对低盐敏感的附生杂藻.     

裸体异鳔鳅(鱼它)人工繁殖与胚胎发育研究

为了解裸体异鳔鳅(鱼它)(Xenophysogobio nudicorpa)人工繁殖和胚胎发育规律，以从金沙江采集到的10尾雌鱼(平均体长17.5 cm,体质量22.3 g)、8尾雄鱼(平均体长15.6 cm,体质量17.5 g)作为亲本，分3批次开展了人工繁殖试验，并观察在水温(20.0±0.5)℃下该鱼的胚胎发育情况。试验结果显示：在水温(15.0±0.5)、(18.0±0.5)、(20.0±0.5)℃的条件下催产，催产剂(雌鱼第1针注射LHRH-A₃ 2μg/kg,第2针注射LHRH-A₃ 10μg/kg+HCG 1 200 IU/kg+PG 8 mg/kg,间距12 h;雄鱼不注射)的效应时间分别为21、15、14 h,受精率分别为8.5%、76.8%、74.5%。将受精卵在水温(15.0±0.5)℃条件下孵化288 h,大部分仔鱼未能正常出膜；当水温升至(18.0±0.5)℃,大部分仔鱼在孵化168 h后破膜而出，但仍有小部分无法正常出膜；当水温升至(20.0±0.5)℃时，仔鱼正常出膜，且出膜时间缩短至120 h。裸体异鳔鳅(鱼它...     

加热条件下鱼翅结构和物性学参数变化

研究了鱼翅在不同加热时间(1、2、3、4 h)条件下组织构造及其物性学参数(凝胶强度、最大破断应变、剪切应力、破断强度)变化,并测定了胶原蛋白含量。通过扫描电子显微镜镜观察鱼翅的组织构造,采用质构仪测定其物性特性。结果表明,随着加热时间的延长,鱼翅的物性学参数变化显著,总体呈减小趋势。加热3 h后即可达到鱼翅较好质构。     

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.     

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.     

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.     

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.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

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。