长吻Wei的营养和饲料研究Ⅱ：温度对摄食,生长及饲料转化效率的影响

在室内流水条件下测定不同温度（１５℃、２０℃、２５℃和３０℃）对长吻Ｗｅｉ幼鱼摄食。生长及饲料转化效率的影响。结果表明：长吻Ｗｅｉ摄食与生长的起始温度为１５℃；适宜温度区为２０－３０℃；最适温度为２５℃左右。水温为１０℃时，长吻Ｗｅｉ基本不摄食。水温为１５－２５℃时，长吻Ｗｅｉ摄食率 、生长率随永温升高而显著增加，２５℃和３０℃组间差异不大。饲料转化效率随水温上升明显提高，但水温升至３０℃时，饲料     

长吻的营养和饲料研究Ⅱ温度对摄食、生长及饲料转化效率的影响

在室内流水条件下测定不同温度（１５℃、２０℃、２５℃和３０℃）对长吻幼鱼摄食，生长及饲料转化效率的影响。结果表明：长吻摄食与生长的起始温度为１５℃；适宜温度区为２０—３０℃；最适温度为２５℃左右。水温为１０℃时，长吻　基本不摄食，水温为１５—２５℃时，长吻摄食率、生长率随永温升高而显著增加，２５℃和３０℃组间差异不大。饲料转化效率随水温上升明显提高，但水温升至３０℃时，饲料转化效率有下降的趋势。长吻幼鱼日投饵量可根据经验公式：Ｃ＝０．１４８Ｔ￣（１．６２６）Ｗ￣（－０．５２１）计算。     

论我国鲟鱼产业发展方向

一、我国鲟鱼养殖的现状和存在的问题目前，各种规格鲟鱼养殖存塘量约在６００万～７００万尾（４０００吨左右），其各种类所占比例（重量）大致为：史氏鲟３５％，杂交鲟２５％，中华鲟２０％，西伯利亚鲟１０％，其他种类１０％。养殖的主要区域为广东、湖北、福建和江、浙、沪，其养殖量所占比例大致为：广东２５％，湖北２５％，福建２０％，江、浙、沪１５％，其他省市合计１５％。鲟鱼为亚冷水性鱼类，生长适宜温度为１５～２６℃，广东和福建尽管冬季的水温较为适宜，但是一般地表水水温超过２６℃长达３～５个月，因此该地区并非鲟…     

温度对条纹石鮨蛋白消化酶活性影响的初步研究

水温１５～２０℃时,条纹石鱼旨各消化器官的重量占鱼体重的百分比大小依次排列为比肝重＞比胃重＞比肠重,而在２５～３０℃时则排列为比胃重＞比肝重＞比肠重;水温１５～３０℃时,随着温度的上升,单位体重中酶蛋白所占的比例呈下降趋势;１５～２０℃时,消化道蛋白酶的活性随着水温的升高而显著增大,超过２０℃时,蛋白酶的活性又呈下降趋势;１５～２０℃时,各消化器官中蛋白酶的比活均上升９倍,２０～３０℃时,肝蛋白酶的比活继续增大,而胃及肠蛋白酶的比活则略有下降。     

加州鲈鱼人工繁殖技术

加州鲈鱼人工繁殖技术陈文龙（浙江省德清县水产局）加州钟属鲈形目、太阳鱼科，为淡水广温性种类。该鱼自然分布范围在北纬２５－５０°，西经７０—１２５°，生存水温１—３６℃，适宜水温１５—２５°。其适应性强，性情温驯，生长迅速且易捕捞，是经济价值高的名贵鱼...     

锚头鳋的测报与预报

锚头鳋是寄生在鱼体表上的一种水生昆生。其由头、胸、腹三部分组成。雄虫不侵害鱼体，营自由生活。雌虫以头部深深扎入鱼体肌内，吸取鱼体营养，胸、腹裸露在外。性成熟后，卵囊增大。产卵时身体呈半透明状，其内有一黑点。水温１３℃时开始繁育，生育期随水温变化而变化，１５～２０℃水温约３５天，２１～２５℃约２８天，３０℃以上只存活２０天，３３℃以上生活受抑制，２０～２５℃生命活动最旺盛。１２００１年测报锚头鳋以成虫寄生在鱼体或水下越冬。２００１年，我们将带有锚头鳋病的草鱼１００千克（其中草鱼３０千克，鲢鱼６５千…     

大黄鱼养殖中几种常见病的防治方法

本尼登虫病 ［病因］本尼登虫寄生而发病。 ［症状］本尼登虫常寄生在大黄鱼、黄鳍鲷、真 鲷、黑鲷、石斑鱼等海水鱼的体表各处，尤其是背部 的前半段较多。本尼登虫在鱼体上寄生时，鱼在水 中焦躁不安，不断狂游，在网或池壁上摩擦，虫体后 固着盘的大小钩将表皮撕破，体表受伤发炎，分泌大 量粘液，严重时贫血、消瘦、体表局部或大面积溃疡 或出现烂颌、烂尾等并发症。 ［治疗］ 方法一：用淡水浸浴，在水温１０—２０℃浸洗１５－ ２０分钟，水温２０—２５℃浸洗１０—１５分钟，水温２５℃ 以上浸洗５—１０分钟，此方法劳动强度大，操…     

山区流水养鱼技术要点

山区流水养鱼技术要点一、水质和鱼池的要求１．水质条件流水养鱼要求水质清新、无臭、无异味，无明显的油膜浮沫，水源充足，水中溶氧不得低于５毫克／升。一年中要有６个月以上的适宜水温，水温一般在２０—３０℃之间，不得低于１５℃。如水温过低，在流水池前增建一个...     

大菱鲆养殖实用技术

本文就大菱鲆养殖的基本技术、条件要求做简单介绍。 一、苗种购入：大菱鲆苗种购入时体长要在５ｃｍ以上，鱼体色泽正常，有活力，无病害、畸形。 二、水温：大菱鲆是冷水性鱼类，养殖适宜水温要求在１０℃－２０℃之间，１４℃-１７℃水温为快速生长阶段。 三、盐度：大菱鲆养殖的适宜盐度２０‰－３２‰之间，２５‰－３０‰最为合适。 四、水质：大菱鲆养殖要求水质无污染，抽取地下海水可直接入养殖池使用，用外海水要进行过滤、杀菌。 五、用水量：根据对大菱鲆的养殖经验，以流水养殖为好。每天换水量至少在５个循环以上，如果水量充…     

大菱鲆养殖实用技术要点

大菱鲆产自英国、法国等欧洲国家的大西洋北部海域，为底栖性鱼类。我国于１９９２年引进大菱鲆进行人工养殖，目前已在山东等地发展到一定规模。大菱鲆肉质鲜嫩，营养价值高，很受消费者欢迎，发展前景看好。现就大菱鲆养殖的基本技术、条件要求做简单介绍。１ 苗种购入 大菱鲆苗种购入时体长要在５ｃｍ以上，鱼体色泽正常，有活力，无病害、畸形。２ 水温 大菱鲆是冷水性鱼类，养殖适宜水温要求在１０～２０℃之间，１４～１７℃为快速生长水温。３盐度 大菱鲆养殖的适宜盐度２０～３２之间，２５～３０最为合适。４水质 大菱鲆养殖要求水…     

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.