单环刺Yi增养殖生物学的研究

单环刺Ｙｉ个体鲜出肉率大致为冬季３９－４７％，春季１７－２７％．食性为滤食性，以水中悬浮性颗粒为食。气温７℃，干露时间持续７２ｈ，均能成活。生活水温是０－３０℃，临界高温３２．５℃，临界低温－４℃。生活的盐度范围是１５－３６，适宜盐度范围２４．９４－３５．７７。     

嘉庚蛸对温度、盐度的耐受性试验

2003年4～10月在试验条件下研究了嘉庚蛸成体对温度、盐度等环境因子的耐受能力。利用温水和冰水调节水温，在温控加热器和生物冰袋的协助下完成温度耐受性试验；通过淡水和海水晶调节试验过程中所需的盐度变化。试验结果表明：嘉庚蛸的适宜温度范围为12．0℃～31．0℃，临界上限水温为35．2℃，临界下限水温为0．5℃；耐受盐度的范围比较广泛，为4．8～48．5，适宜养殖的盐度为18．4～33．1。较高的耐受性范围可以保证嘉庚蛸更好地适应其生存的环境，不至于由于环境因子的激变造成嘉庚蛸的大规模死亡。因此，人工养殖和育苗过程中，保持环境因子的稳定是获得高孵化率的先决条件。     

大黄鱼幼鱼对若干环境因子的适应性试验

在有实验装置的人工控制环境条件下，以每批100尾大黄鱼幼鱼进行光照强度、水温、溶氧量、盐度等的单因子适应性实验以及对温度、溶解氧和盐度正交适应性实验。其结果是：全长29～44mm，平均全长为39mm的幼鱼．适光范围为520～5500lx，最适范围为780—1830lx；适宜温度为21．4～24．9℃，最适温度为22．4～24．9℃；适宜盐度为25．5～28．8，最适盐度为26．8～28．8；适宜溶氧量为4．70～5．38mg／L，最适溶氧量为4．76～5．15mg／L。全长为59～86mn，平均全长为75mm的幼鱼，适光范围为620～5500lx，最适光照强度为850～1820lx；适宜温度为22．3～25．0℃，最适温度为22．3～24．3℃；适宜盐度为26．5～28．5，最适盐度为26．7～27．8；适宜溶氧量为4．65～5．38mg/L，最适溶氧量为4．75～5．21mg／L。温度对幼鱼的影响极为显著，盐度和溶解氧的影响次之。     

莫桑比克鳗鲡养殖生物学主要特性研究

对莫桑比克鳗鲡（Anguillamor morata）玻璃鳗经形态学鉴定品种后，开展了主要养殖生物学特性研究。耐受高温和低温分别为39℃和7℃，适宜生存水温15℃～33℃；耐受盐度与水温相关，水温30℃致死盐度2．9％，适宜盐度小于1．1％，20℃致死盐度2．7％，适宜盐度小于1．8％，10℃致死盐度2．1％，适宜盐度小于2．0％；耐受pH值与水温相关，30℃致死pH值分别为3．5和11．0，适宜pH值6．0—7．0，20℃致死pH值分别为4．0和11．0，适宜pH值6．0～8．0，10℃致死pH值分别为3．5和10．5，适宜pH值5．5—8．5。常用药物S高聚碘、二氧化氯、三氯异氰尿酸、苯扎溴铵、溴氯海因、甲醛、敌百虫的安全浓度高于或接近常用浓度，硫酸铜、溴氰菊脂乳油、氯氰菊脂、甲苯咪唑的安全浓度低于常用浓度。水体中非离子态氨的安全浓度为2．51mg／L，亚硝酸氮的安全浓度为55．12mg／L。     

盐度与pH对云纹石斑鱼胚胎发育和仔鱼活力的影响

为探讨盐度、pH对云纹石斑鱼Epinephelus moara胚胎发育和仔鱼活力的影响,采用单因子实验的方法,在水温22±0．2℃条件下,将受精卵在不同盐度（5、10、15、20、25、30、35、40和45）、不同pH（5．5、6．0、6．5、7．0、7．5、8．0、8．5、9．0和9．5）下孵化,观察比较其孵化率HR、畸形率DR以及对初孵仔鱼活力和仔鱼培育周期的影响。并在上述设定条件下,进行了初孵仔鱼耐受试验,测定其存活率SR及生存活力指数（SAI）。结果表明,云纹石斑鱼胚胎发育的最低和最高临界盐度分别为10和45,最低和最高临界PH分别为6．O和9．5;盐度、PH的适宜范围分别是20～40、6．5～9．0,最适范围分别是30～35、7．5～8．0。仔鱼生存盐度、pH的适宜范围分别是20～35、6．0～9．0,最适范围分别是25～30、7．5～8．0。     

方斑东风螺对盐度适应性的研究

通过实验生态学的方法，在温度28．2～29．7℃、pH7．6—8．3的条件下，研究了养殖方斑东风螺（Babylonia areolata）的适宜、最适生存盐度及适宜、最适生长盐度，以期为养殖生产提供科学依据。生存临界盐度界定为120h50％死亡的盐度（120hLS50），其范围为适宜生存盐度；生长临界盐度界定为增长率为最佳一组30％所对应的盐度，其范围为适宜生长盐度；把经过多重比较结果显示无显著差异的存活率或13生长量最高的几个实验组所对应的盐度范围作为最适生存或生长盐度。研究结果表明，方斑东风螺适宜生存盐度为19．18～41．39，最适生存盐度为26．0—34．4；适宜生长盐度为19．28～39．96，最适生长盐度为26．0—31．6。当盐度变化超出最适范围时，养殖方斑东风螺对低盐更为敏感。     

莫桑比克鳗鲡对温度、盐度和pH的耐受性试验

就莫桑比克鳗鲡对水温、盐度和pH的耐受性进行了初步研究.试验结果表明,适宜水温为12.0～35.0℃,临界上限为40.0℃.临界下限为0℃;适宜盐度为0～15.临界极限为45;适宜pH为4.0～9.5,临界上限为11.0,临界下限为2.5.     

理化因子对原绿球藻生长及其色素含量的影响

以COA为基础培养基，进行了光照、温度、盐度等理化因子对原绿球藻生长和色素含量影响的单因子试验。试验结果表明，原绿球藻适宜生长的光照度为500～2500lx，最适光照度为500～1000lx：适宜生长的温度为10～30℃，最适温度为25～30℃；适宜生长的盐度为0～44．9，最适盐度为13．7～33．4；适宜生长的pH5～11，最适pH8～10；最适氮源为NH4-N，其次为（NH2）2CO；适宜生长的氮（NH4Cl）质量浓度为5～25mg／L，最适质量浓度为15～25mg／L。理化因子对该藻色素含量的影响与其生长相吻合。     

珍珠龙胆石斑鱼对水温、盐度和溶解氧的耐受研究

为研究珍珠龙胆石斑鱼对海水温度、盐度、溶解氧等主要环境因子的耐受,选择健康活泼的珍珠龙胆石斑鱼个体,采用渐变式方法达到设计的要求,进行试验。结果表明:珍珠龙胆石斑鱼对水温、盐度和溶解氧耐受范围较广,适宜水温为20～35℃,临界下限水温为10℃,临界上限水温为39℃;适宜盐度为11～40,临界下限盐度为3,上限盐度可到45以上;耐受低氧:DO_1为0.70 mg/L,DO_(50)为0.67 mg/L,DO_(100)为0.60 mg/L。     

温度和盐度对菲律宾蛤仔稚贝生长及发育的影响

本文叙述了，在室内控制条件下，温度和盐度对菲律宾蛤仔稚贝生长及发育的影响。蛤仔稚贝生长的适宜水温为15—30℃，其中以25℃为最好。在此温度范围内，稚贝生长迅速，成活率高达80％以上。稚贝对10℃以下的低温有强的忍耐性，也能忍耐35℃的高温，其死亡的临界温度在40℃左右。稚贝生长的适宜盐度为14．0—33．5‰，最适盐度是20．5‰左右。在此盐度范围内，稚贝发育整齐，成活率高达85％以上。生长的盐度下限和上限分别为7．5‰和40．0‰左右。幼虫变态的适宜盐度在20．5～33．5‰之间，在此盐度范围内，幼虫成活率为65％以上。盐度在27‰时幼体的成活率最高，达到92．5％。幼虫变态的盐度下限为7．5‰左右，而上限则在于40．0—46．5‰之间。     

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.     

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.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

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.