养殖斑点叉尾鮰的常见病害及防治技术

斑点叉尾鮰，又称河鲶、沟鲶、美洲鲶，原产于北美洲，具有食性杂、抗病力强、适应性广、生长快、肉质细嫩、营养丰富、经济价值高等特点，是一个有着广泛前景的优质养殖品种，也是我国引进的较为成功的养殖品种。斑点叉尾鮰的疾病较多，从病毒感染到寄生虫的侵袭均可造成批量死亡。因此，该鱼的病害防治是一项十分重要的工作。     

无公害斑点叉尾鮰养殖技术及病害防治

斑点叉尾鮰，原产于美洲，又称沟鲶、美洲鲶、河鲶。该鱼由于具有生长快、适温范围广、抗病力强。斑点叉尾鮰有三大优点：肉质细嫩、味鲜美、富含蛋白质和不饱和脂肪酸；摄食颗粒饲料，饲料系数低（1．3-2．0），适于集约化和规模化养殖；无肌间刺、适于机械加工、宜作快餐原料。斑点叉尾鮰可池塘单养、混养、以及网箱等方式的养殖。     

斑点叉尾(鮰)网箱养殖高产技术研究

进行了斑点叉尾(鮰)鱼苗池塘强化培育、网箱养成鱼种、鱼种网箱越冬和商品鱼网箱养殖试验.(鮰)鱼苗网箱培育当年个体重达22.98 g,网箱越冬成活率94.2%.网箱养商品(鮰)净产51.3 kg/m3,个体均重341.9 g,饲料系数1.70.     

斑点叉尾鮰池塘养殖技术

斑点叉尾鮰具有肉质细嫩、生长快、个体大、易饲养、经济价值高等特点。原是肉食性鱼,经驯化为杂食性鱼类。为推广新品种养殖,提高优质鱼产量,我们水产站2002年首次引进斑点叉尾鮰并试养成功。现将试验总结如下: 一.池塘与放养 1.池塘条件 选择1亩养鱼池,池塘水深保证1.2米,进排水方便,淤泥20厘米,水源为井水、自来水,水质     

斑点叉尾鮰无公害养殖技术

斑点叉尾鮰原产于美洲，是一种大型经济鱼类，经长期驯化后，已成为以植物性饲料为主的杂食性鱼类．斑点叉尾鮰具有生长快、适温范围广、抗病能力强、肉味美、出肉率高等特点，深受广大养殖户和消费者喜爱。随着国内外市场对斑点叉尾鮰需求急增。刺激了国内斑点叉尾鮰养殖，特别是一些内陆省份。相继建立了养殖基地。现将斑点叉尾鮰无公害养殖技术介绍如下。     

斑点叉尾Hui养殖技术及病害防治

我国自美国引进斑点叉尾Hui，并深入进行了养殖技术研究，已在全国20多个省，市，自治区推广应用，十几年来产值数达十亿元，斑点叉尾Hui病害及防治技术的研究，解决了养殖中重大技术难点，它的应用取得了巨大经济效益和社会效益。     

斑点叉尾鮰养殖技术与病害防治

斑点叉尾鮰,又名沟鲶,属鲶形目,鮰科鱼类。斑点叉尾鮰属杂食性鱼类,贪食、喜群食,并喜欢在弱暗光条件下摄食。幼苗期(体长<1O.0cm)以吞、滤食为主,体长>10.0cm时以吞食为主。天然水域幼鱼以摄食水生昆虫为主,成鱼主要摄食底栖动物、小杂鱼、虾类、藻类、水生植物及其种子、有机碎屑等。其肉味鲜美,细嫩,营养丰富,且具有降血压、降血脂的功效,深受广大消费者的喜爱。因其具有适温范围广、抗病力强、易饲养、成活率高、生长快、起捕率高等特点,适合我国绝大部分地区淡水水域饲养。且易于食用和适于加工,是水产深加工的原料之一,因而斑点叉尾…     

池塘养殖斑点叉尾(鱼回)鱼病防治技术

从斑点叉尾(鱼回)的生物学性状出发,介绍了池塘养殖过程中常见病害的流行病学、发病机理和发病症状,并提出了针对性的防治措施以及斑点叉尾(鱼回)的综合病防措施.     

美国斑点叉尾鮰无公害养殖技术

美国斑点又尾鮰具有食性广、生长快、适应性强、抗病力强、品质好、市场潜力大等特点，是当前推广养殖的优良品种。2001～2004年我们对该品种进行了养殖，现将其无公害养殖技术总结如下：     

水库网箱养殖斑点叉尾鮰技术

斑点叉尾鱼回又称沟鲶、河鲶、美洲鲶。由于这种鱼具有适应性强、生长快、易饲养、易起捕以及肉质鲜美等优点,因而成为世界闻名的养殖品种和游钓的对象。它适合于我国绝大部分地区养殖,是一种具有发展前景的优良养殖鱼类。利用水库养殖可提高水库水体生产效率,实现高密度、集约化养殖,但养殖实践中应把握以下几关。一、选址关斑点叉尾鱼回是温水性淡水鱼类,适温范围0～38℃,最适生长温度为21～26℃,在水温低于10℃时,基本停止摄食和生长。在纯淡水中生长良好,在盐度为1.4%的水中仍能生活。所以,适宜于网箱养殖的水库,必须水温常年在0～38℃…     

Multi-Locus DNA Fingerprinting of Channel Catfish Ictalurus punctatus

Abstract.— Similarities among multi-locus DNA fingerprints of five channel catfish Ictalurus punctatus strains and the ability to identify the strain of a fish based on its fingerprint pattern were investigated. Five restriction enzymes and 13 multi-locus DNA probes were screened to identify enzyme-probe combination useful for DNA fingerprinting channel catfish. Restriction enzymes Hinf I and Dpn II, in combination with probes (CAC)n, (CGC)n, (CTC)n, (ATCC)n, and (GATA)n, produced useful fingerprints (20–30 resolvable bands for each enzyme-probe combination). Thirty individuals (3 pools of 10 individuals each) from each of five channel catfish strains (albino, Mississippi normal, USDA-102, USDA-102 select, and USDA-103) were fingerprinted with all useful enzyme-probe combinations. Band sharing among samples was higher within strains than among strains and band sharing among strains was higher for strains whose breeding history indicated a high degree of relatedness. Individual fingerprints of 18 fish from each of the USDA-102 select and USDA-103 strains revealed no strain-specific bands, but several diagnostic bands (present at high frequencies in either USDA-102 select or USDA-103 strains and at a low frequencies in other strains) were identified. Band sharing at diagnostic bands was used to correctly identify fish as USDA-102 select or USDA-103 strains with 82% accuracy from fingerprints of 17 USDA-102 select strain fish, 18 USDA-103 strain fish, and 38 fish collected from three commercial farms.     

斑点叉尾鮰的主要细菌病及其防治措施

近年来,养殖斑点叉尾鮰的细菌性传染病频繁暴发,危害严重,给养殖户造成了巨大的经济损失。文章对斑点叉尾鮰肠道败血症、柱形菌病、出血性败血症、烂尾病等常见细菌病的病原、流行情况、病理变化进行了详细论述,并提出了一些行之有效的防治措施。     

美国红鮰鱼人工繁殖试验

从人工饲养的成鱼中挑选体色单纯、红色较深的个体作后备亲鱼进行强化培育，待其性腺发育成熟后，注射LHRH—A2催熟催产。催熟剂量为每千克鱼体重2～3μg(雄鱼不催熟)，催产剂量为8μg(雄鱼剂量减半)。试验结果，雌鱼的催产率达70．6％；共获受精卵大约18万粒；孵化出鱼苗约16万尾，平均孵化率88．9％；经培育，共获体长3．5cm的鱼种14．82万尾，鱼种的平均培育成活率达92．6％。试验结果表明，亲鱼培育是美国红鮰鱼人工繁殖取得成功的关键，而要获得遗传性状稳定的红鮰鱼鱼种，亲鱼的筛选至关重要；美国红鮰鱼生长快，抗病力强，产量高，肉质鲜嫩，是优良的养殖品种，可以在国内推广养殖。     

壶状臂尾轮虫高效培养技术

2008年4月,四川眉山一水库中养殖的斑点叉尾鮰出现大量死亡,病鱼主要表现为腹部极度膨大,解剖时有大量腹水流出,可见各内脏器官广泛出血.发病最高峰时每天的死亡量可达500多千克,给养殖户带来了巨大的经济损失.经笔者对死亡鱼进行解剖及对致病菌分离、鉴定,最终确定为维氏气单胞菌感染.现将该病例的诊断及防治情况介绍如下.     

Variation in Channel Catfish Ictalurus punctatus Flavor Quality and its Quality Control Implications

Abstract Producers may capture two to three channel catfish Ictalurus punctatus L. for flavor analysis from ponds scheduled for harvest. If off-flavors are not present in several consecutive fish samples, the population may be considered acceptable for harvest. However, instrumental analysis of the muddy/earthy off-flavor metabolites 2-methylisoborneol (1-R-exo-1,2,7,7-tetramethyl-bicyclo-[2,2,1]-heptan-2-ol) (MIB) and geosmin (lα, 10β-dimethyl-9α-decalol) concentrations in approximately 80 catfish from each of three commercial ponds found both acceptable (on-flavor) and unacceptable (off-flavor) individuals within a single pond (i.e., mixed-flavor populations). Ascertaining the frequency of mixed-flavor populations by instrumentally determining the off-flavor metabolite concentration in muscle tissues from a large number of fish sampled from many ponds at several locations over time is not currently feasible. However, analysis of 12,725 commercial processor flavor assessments collected in 1994 and 1995 indicated 120 instances of individual ponds yielding off-flavor fish followed by on-flavor fish in one day or less. Reports indicate that fish require approximately four days to depurate off-flavors fully, suggesting that a proportion of these rapidly changing flavor assessments may reflect the stochastic selection of fish from mixed-flavor populations rather than a complete and rapid conversion of the flavor quality of entire populations. Factors that contribute to the occurrence of mixed-flavor-populations have not been identified fully. However, increased proportion of fat in catfish fillet tissues has been reported to be correlated with a greater retention of MIB by fish. In this investigation, fish fat contents ranged from 4.45% to 30.45%, and were positively correlated (P < 0.0001) with MIB concentrations. Additionally, the spatial distributions of algal populations within certain commercial catfish ponds were not uniform, and the sensory analysis of the flavor intensity of MIB and geosmin in catfish was more variable than the assessment of the intensity of chickeny and nutty flavors. Probability analysis indicated that in certain mixed-flavor populations there was a 10 to 25% probability of a shipment of fish being rejected due to the random collection of only on-flavor fish prior to harvest followed by the post harvest capture of at least one off-flavor fish. In addition, a chance of no off-flavor fish being sampled from a population containing a proportion of unacceptable fish was indicated. At current sample sizes, replacing sensory analysis with instrumental analysis would not completely avoid problems associated with sampling mixed-flavor-populations. Until effective means to reduce/avoid off-flavor metabolite accumulations in fish are widely available, careful attention to proper sensory evaluation protocols, an enhanced attention to pond conditions that affect flavor quality, the production of leaner more uniform populations of fish, and optimizations of sampling strategies offer the most practical near-term augmentations of current practice.     

Behavioral Interactions in Juvenile Channel Catfish,Ictalurus punctatus

Behavioral interactions among juvenile channel catfish, "Ictalurus punctatus," were observed, and fixed action patterns were described and anlyzed. Dominant fish engaged regularly in aggressive activities and never in submissive activities, whereas subordinate fish were observed in submissive activities on a regular basis and rarely in those that were aggressive. Activity levels were significantly higher in dominant fish; however, there was no difference in activity levels between pairs of equal and unequal size fish. A factor analysis indicated that there were three general categoris of behavior in juvenile channel catfish. In addition, two behaviors (which appeared to be displacement activities) were functioning in agnostic encounters. Plasma cortisol concentrations measured in sigle fish and pairs of fish in aquaria and individuals from a holding tank indicated that the least amount of stress occurred in fish that were not interacting with any other individuals. Cortisol levels, however, were lower that those associated with stress levels in fish from other studies.     

Low-Quality Diets for Growout of Channel Catfish,Ictalurus punctatus

Abstract

A feeding trial was conducted to evaluate low-quality diets for growout of pond-raised channel catfish. Five practical diets containing various levels of protein (10-28%) of varying quality (with or without animal protein and/or soybean meal), and with or without certain nutrient supplements (vitamin, minerals, lysine, or fat) were fed to channel catfish, Ictalurus punctatusstocked in 0.04-ha earthen ponds at a rate of 17,290 fish/ha. The diets were as follows: (1) 28% protein, nutritionally complete control; (2) 28% protein without supplemental vitamins, minerals, or fat; (3) 18% protein + supplemental lysine, vitamins, and minerals, but without animal protein; (4) 10% protein without animal protein, soybean meal, or supplemental vitamins and minerals; and (5) 10% protein + supplemental lysine, vitamins, and minerals, but without animal protein or soybean meal. Each diet was fed once daily to apparent satiation to fish in five replicate ponds for a single growing season. Fish fed diets containing 18% or 28% protein without supplements had similar diet consumption rates and weight gain as those fed the 28% control diet, but the fish fed the control diet converted diet more efficiently. Fish fed the 10% protein diet without supplements consumed less diet, converted diet less efficiently, and gained less weight than fish fed diets containing higher levels of protein. The addition of supplements to the 10% protein diet increased weight gain and processing yield as compared to fish fed the 10% protein diet without supplements. Body fattiness increased, fillet protein decreased, and carcass, fillet and nugget yields decreased as dietary protein decreased. The data show that pond-raised channel catfish can be grown effectively on a diet containing 18% protein that is of relatively low quality, but fattiness is increased and processing yield is decreased. However, because of the negative aspects of this diet, we would not recommend it for general use in commercial catfish culture. It could be used where fattiness and processing yield are not of consequence, such as recreational ponds. For that matter, the 10% diet without supplements could be used as well in these situations if maximum growth is not desired.     

Environmental Assessment of Channel Catfish Ictalurus punctatus Farming in Alabama

An environmental assessment was made of Alabama channel catfish Ictalurus punctatus farming which is concentrated in the west‐central region of the state. There are about 10,000 ha of production ponds with 10.7% of the area for fry and fingerlings and 89.3% for food fish. Food fish production was about 40,800 tons in 1997. Watershed ponds filled by rainfall and runoff make up 76% of total pond area. Water levels in many of these ponds are maintained in dry weather with well water. The other ponds are embankment ponds supplied by well water. Harvest is primarily by seine‐through procedures and ponds are not drained frequently. The main points related to Alabama catfish farming and environment issues are as follows: 1) catfish farming in Alabama is conservative of water, and excluding storm overflow, about two pond volumes are intentionally discharged from each pond in 15 yr; 2) overflow from ponds following rains occurs mostly in winter and early spring when pond water quality is good and stream discharge volume is high; 3) total suspended solids concentrations in pond effluents were high, and the main sources of total suspended solids were erosion of embankments, pond bottoms, and discharge ditches; 4) concentrations of nitrogen and phosphorus in effluents were not high, but annual effluent loads of these two nutrients were greater than for typical row crops in Alabama; 5) ground water use by the industry is about 86,000 m³/d, but seepage from ponds returns water to aquifers; 6) there is little use of medicated feeds; 7) copper sulfate is used to control blue‐green algae and off‐flavor in ponds, but copper is rapidly lost from pond water; 8) although sodium chloride is applied to ponds to control nitrite toxicity, stream or ground water salinization has not resulted from this practice; 9) fertilizers are applied two or three times annually to fry and fingerling ponds and occasionally to grow‐out ponds; 10) hydrated lime is applied occasionally at 50 to 100 kg/ha but this does not cause high pH in pond waters or effluents; 11) accumulated sediment removed from pond bottoms is used to repair embankments and not discarded outside ponds; 12) sampling above and below catfish pond outfalls on eight streams revealed few differences in stream water quality; 13) electricity used for pumping water and mechanical aeration is only 0.90 kW h/kg of production; 14) each metric ton of fish meal used in feeds yields about 10 tons of dressed catfish. Reduction in effluent volume through water reuse and effluent treatment in settling basins or wetlands does not appear feasible on most farms. However, some management practices are recommended for reducing the volume and improving the quality of channel catfish pond effluents.     

Biochemical Oxygen Demand in Channel Catfish Ictalurus punctatus Pond Waters

A study of the biochemical oxygen demand (BOD) of waters from ten channel catfish ponds at Auburn, Alabama, revealed that the 5-d BOD (BOD₅) seldom exceeded 8 mg/L and that the ultimate BOD (BOD_u) was usually less than 30 mg/L. Water samples from catfish ponds usually needed to be diluted only 2 or 3 times to permit BOD₅ measurements, and nitrification occurred even during a 5-d incubation period. Catfish pond waters were not extremely high in ammonia nitrogen concentration, and ammonia nitrogen introduced in the ammonium chloride-enriched dilution water caused an appreciable increase in BOD of some samples. Plankton respiration is a major component of carbonaceous BOD (CBOD) in catfish pond waters. Thus, the BOD is not expressed as rapidly during 5-d incubations as in typical waste-water. The ultimate BOD (BOD_u) would be a good measurement of oxygen demand for catfish pond effluents, but it is difficult to measure. Data from this study suggest that BOD_u can be estimated from BOD₅, but the correlation is not strong ( R ²= 0.62). An alternative is to develop a short-term BOD measurement specifically for effluents from channel catfish and other aquaculture ponds. This study suggests that a 10-d BOD conducted without nitrification inhibition or addition of ammonia nitrogen in dilution water might be a better alternative to standard BOD₅ or BOD_u measurements normally used in wastewater evaluation.     

In Search of the Cause of Proliferative Gill Disease in Channel Catfish,Ictalurus punctatus:

A two-year study was conducted on three ponds at a commercial channel catfish, Ictalurus punctatus, farm that experienced severe losses of channel catfish to proliferative gill disease (PGD) during the winter of 1988/1989. Low levels of mild PGD persisted throughout the year. Outbreaks of PGD with resulting mortalities occurred in both hot and cool months. Mortalities associated with PGD occurred in Pond 37 in its first vear of production and in Pond 42 in both its fist and second years of production; Pond 42 had been drained and dried following a PGD outbreak in the spring of its first year. PGD-related mortalities did not occur in Pond 21 in either its third or fourth years of continual production, despite the presence of histologically detectable PGD in the third year. Hennegiya exilis and Sphaerospora were only occasionally observed in PGD-affected channel catfish. Seasonal changes in PGD prevalence were correlated with changes in myxozoan infection of small mud-dwelling worms, Dero digitata (Oligochaeta: Naididae). The myxozoan is an undescribed species of Aurantiactinomyxon (Actinomyxea: Triactinomyxidae). D. digitata and isolated spores of Aurantiactinomyxon sp. were the only pond organisms that produced PGD in laboratory experiments. Comparison of the oligochaete populations of the study ponds suggested that differences in PGD prevalence in channel catfish raised in "old" and "new" ponds may be related to oligochaete population diversity. Channel catfish naturally infected with PGD recovered completely when held in tanks supplied with well water.