鲶鱼苗种培育技术

一、苗种培育 鲶鱼苗种培育全过程大致可分为四个阶段进行: 1.免投喂期:鱼苗刚出膜,全长约0.7～0.8厘米。此时,鱼苗的卵黄囊还未消失,鱼苗集群于池底角落,微微颤动,鱼群显青黄色,只有少数鱼苗离开池底无目的游动,     

杂色蛤苗种中间培育技术

一、池塘选择与清整。1．池塘条件 试验池塘系新开池塘，位于沿海堤外高潮区滩涂，泥沙底质，每个塘口面积2～5亩不等，海水水质达到无公害海水养殖用水水质标准，全年海水盐度在16‰-25‰之间，pH值7．0-8．5，池塘最大蓄水深度1．2～1．5米。     

鲶鱼的人工繁殖及苗种培育技术

鲶鱼（Silurusasot。）属鲶形目、给科、鲶属。鲶鱼不仅生长快,个体大,而且耐低温,耐低氧。同时肉质细嫩,营养丰富,味道鲜美,属高蛋白低脂肪的食品,深受消费者欢迎。目前国内正在开发利用鲶鱼资源,满足市场需求,为了解决鲶鱼苗种的问题,本文将鲶鱼的人工繁殖及苗种培育技术措施总结如下：1．鲶鱼的人工繁殖（1）亲鱼的选择从池塘或湖泊捕捞群体中选择体重在0．5－2kg之间,无病无伤,体质健壮的给鱼作为繁殖亲本。雌鱼腹部膨大,松软有弹性,轻压腹部能挤出卵粒,雄鱼腹部狭小,轻压腹部能挤出白色精液,雌雄比例为2：1。（2）雌…     

鲶鱼的人工繁殖和苗种培育试验

鲶鱼的人工繁殖和苗种培育试验方耀林，余来宁，郑卫东（中国水产科学研究院长江水产研究所）鲶鱼，属鳝形目，鲶科，俗称“土鲶”，可生活在江河、湖泊以及沟渠、堰塘等小型水体中，为底栖性的肉食鱼类，适应性广，以各种小杂鱼、小虾、软体动物等为其对象，经人工驯养，...     

泥蚶苗种中间培育高产技术

泥蚶俗称“花蚶”,属热带和温带贝类,分布于我国山东半岛以南的沿海海域,是沿海各省重要养殖对象。泥蚶苗种中间培育就是指在高潮区滩涂上筑坝蓄水培育人工繁殖的泥蚶苗,生产成泥蚶蚶豆供应养殖生产。这是近年来新兴的一项养殖生产方式,充分解决了因海区污染造成的自然资源量不足的问题。现已成为发展养殖生产、增加资源量的必需途径。目前各地泥蚶苗中间培育面较广,但成活率等技术指标普遍不够高。本文根据近年来的实践经验,归纳出培育过程中各项重点技术措施与广大同仁交流。一、养殖条件1.场址选择:要求选择在海区没有污染、潮流畅通、地…     

小网箱繁殖培育鲶鱼苗种技术

鲶鱼味道鲜美,肉嫩少利,是餐桌。的美味佳肴。随着消费量的上升以之江河野生数量的剧减,近年不少地了对其进行驯化养殖,养殖规模和范a不断扩大,苗种供不应求。而利用l。网箱进行鲶鱼的繁殖和苗种培育z有投资少,容易饲养管理,能充分u用现有水面,不占其它场地等优i。现根     

鲶鱼人工繁殖与苗种培育初探

一冬龄鲶鱼达到性成熟，４—６月为鲶鱼的繁殖期。催产药物及剂量为每公斤雌鱼用ＰＧ３—４ｍｇ＋ＨＣＧ８００ＩＵ；雄鱼减半。共催产５批１６０组，获受精卵５９万尾，出苗４２万尾。鲶鱼苗从孵出培育１６天可育成３５—４０ｍｍ的夏花。     

池塘培育斑点叉尾鮰苗种技术

斑点叉尾 鱼回 亦称沟鲶 ,属鲶形目 鱼回 科鱼类 ,是美国主要淡水养殖鱼类 ;该鱼具有适应范围广、食性杂、个体大、生长快 ,抗病能力强 ,肉质细嫩鲜美等优点。为了提高该鱼在北方池塘养殖产量 ,我们 1998年做了斑点叉尾鱼回 池塘苗种培育试验。1　材料与方法1 1　池塘条件本实验选在吉林农大水库渔场池塘 ;池塘面积 2 0亩 (斑点叉尾 鱼回 苗种培育池面积过大 ,不利于驯化饲养 ) ,养殖期间平均水深 1 5ｍ左右 ,池塘底泥在 2 0～ 30ｃｍ之间 ,注排水方便 ,水量充足 ,水质良好。 6月 18日全池用生石灰 2 6 0ｋｇ遍洒 ,6月 2 0日用网拉池底 …     

青蛤大规格苗种规模化培育技术

选择进排水方便的堤内连片田块建造苗种一级培育池，每个池为300米^2，池底整平后铺黑色薄膜，再均匀铺上一层5厘米左右的沙性细土；选择堤外高涂建筑扩苗、分级分养的二、三级培育池，每个池面积为2-4亩，池塘用泥浆泵从外面抽进服沃的底泥10-20厘米，再用旋耕机耕翻一遍。     

高盐碱池塘鱼类苗种培育技术

在内陆干旱少雨地区.有大面积不宜耕作的盐碱滩地。因表土层聚集大量盐碱成分,若建鱼池,则池塘盐碱度较高,有的塘水总碱度高达10毫克当量/升,甚至超过30毫克当量/升,含盐量>4‰;pH值一般也较高,大都在9.0以上,给鱼类苗种培育带来很大困难。因而。生产中应采取措施.改善池塘水环境,给鱼苗、鱼种及饵料生物提供适宜的生长条件。     

池塘主养土鲶高产试验

0.4hm2池塘放养规格为5.0cm的土鲶(Silurus asotus)夏花鱼苗,密度4.5万尾/hm2。经92d饲养,平均规格405g;产量11 846.25kg/hm2;饵料系数3.50;利润8.0万元;投入产出比1∶2.47;出塘率65.0%。     

鲇鱼淋巴样器官的发育

鲇鱼淋巴样器官的发育ＯＮＴＯＧＥＮＹＯＦＬＹＭＰＨＯＭＹＥＬＯＩＤＯＲＧＡＮＳＩＮＣＡＴＦＩＳＨ（ＳＩＬＵＲＵＳＡＳＯＴＵＳＬ．）￥ＺｈｏｎｇＭｉｎｇｃｈａｏ；ＨｕａｎｇＺｈｅ（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｌｏｇｙ，ＺｈｏｎｇｓｈａｎＵｎｉｖｅｒｓ...     

洞庭湖土鲶染色体核型分析

采用PHA 和秋水仙素体内注射法,研究洞庭湖土鲶的染色体核型.试验结果表明,洞庭湖土鲶染色体组由58 条组成,按着丝粒位置可分为4组,m 组有12对染色体,sm 组有8 对染色体,st 组有7 对染色体,t 组有2对染色体,每个染色体均有相应的同源染色体.洞庭湖土鲶的2n=58,NF =98,其核型公式为:2n =24m+16sm+14st+4t.     

鲇胚胎及其仔鱼发育的连续观察

鲇的成熟卵为典型的多黄卵,为不完全盘状卵裂;水温(24±1)℃时,鲇胚胎发育历时35 h,总积温840~875℃.h;脱膜后第1 d,仔鱼口未形成,2日龄口基本形成,口裂宽(B)与日龄(d)的关系可表示为:B=0.0165 0.3282d(r=0.9756,n=7,P<0.01,2≤d≤8);仔鱼孵出后第3 d开口摄食,仔鱼存在混合营养期,持续时间1 d,仔鱼开口摄食的适口食物为枝角类;发育至8日龄时,仔鱼期结束,此时鲇鳍褶消失,鳍条分化,外形与成鱼相似。     

池塘主养白斑狗鱼高产试验

2005年4月初至年底进行了白斑狗鱼池塘主养试验,共选放体长5 cm的优质鱼苗5000尾,并搭配适量鲢鱼苗。成活率达90%,平均质量550 g/尾,最大个体1.4 kg,平均产量达9375 kg/hm2,投入产出比为1∶2.64,饵料系数约5,取得了良好的经济效益。     

杂交鲶(怀头鲶♀×鲶♂)人工繁殖与苗种培育技术

采用捕自黑龙江水域的怀头鲶为母本，鲶鱼为父本，应用自制催产药物DOS与LRH-A2、HCG进行人工催产，使催产率、受精率分别达到92％和88％。20-21．5℃水温条件下43h孵化出苗，孵化率75％。出膜仔鱼体长3．93mm，7．83mm下塘，池塘培育8天达到34．08mm，培育成活率50％。     

Edwardsiella tarda infection in Korean catfish,Silurus asotus,in a Korean fish farm

Mass mortality of Korean catfish, Silurus asotus, occurred in a culture farm situated in Jeollabukdo Province, Korea. The cumulative mortality rates reached up to 5% of the total fish in the farm per day. In clinical signs, the affected fish showed abdominal distension, vent protrusion, enteritis, liver congestion and abscess‐like lesions in enlarged spleen and kidney. Histopathologically, in the liver, hepatocytes lost fat and underwent atrophy or necrosis. The spleen showed necrotized splenocytes and a haemorrhagic pulp. In the kidney, glomerular destruction, degeneration of renal tubular epithelial cell and haemorrhage were observed. However, necrotic muscular lesions were not observed. A pure bacterial isolate was obtained from the liver, spleen and kidney lesions of affected fish. Experimental infection of normal catfish with the isolate resulted in the development of clinical signs similar to those seen on the farm. The isolates were identified as Edwardsiella tarda through biochemical tests (99.4%) and analysis of bacterial genes (16S rDNA) sequences (98%). The bacteria possessed two virulent genes: sodB and katB genes. These results suggest that E. tarda can act as a pathogen of farmed catfish. This is the first report showing that E. tarda caused mortality in cultured Korean catfish.     

Haematological and biochemical alterations in Korean catfish, Silurus asotus, experimentally infected with Edwardsiella tarda

This study determined the haematological changes in Korean catfish, Silurus asotus , experimentally infected with Edwardsiella tarda . Twenty-four or 48 h after infection with 1 × 10⁴ colony-forming units (CFU) mL⁻¹ of E. tarda , the fish were anaesthetized and the blood was collected. The haematological and biochemical tests included haematocrit (Ht), haemoglobin (Hb), leucocyte counts (Lc), total calcium (Ca), total protein (TP) concentration, alkaline phosphatase (ALP), glucose (GLU), aspartate aminotransferase, lysozyme and differential leucocyte populations. After 24- and 48-h infection, the values of Ht, Hb, Lc, TP, ALP and GLU were significantly decreased with respect to the control. Aspartate aminotransferase and lysozyme activity in both the 24- and 48-h groups exhibited higher levels compared with those in the control. However, the bacterial infection did not induce any significant alteration in the Ca concentration. After the 48-h infection, neutrophils and macrophage populations were reduced whereas lymphocytes were increased with respect to those in the control and the 24-h infection groups. The present study demonstrates that E. tarda infection causes haemato-biochemical responses that are related to the general physiological condition and defence system in catfish.     

鲇仔、稚鱼消化系统胚后发育的组织学观察研究

通过石蜡包埋切片法对鲇(SilurusasotusL.)仔、稚鱼消化系统胚后发育进行了较系统的组织切片观察。本研究描述了全长5.0～22.5mm的鲇摄食器官、消化器官胚后发育的组织学结构特征。观察发现,1～3日龄为内源性营养阶段,卵黄囊很大,2日龄消化道出现裂缝状腔隙,3日龄基本贯通但未开始摄食;4～6日龄为混合营养阶段,卵黄囊被逐步吸收,主要靠吞食轮虫、小型枝角类等为食;6日龄以后卵黄囊消失,进入外源性营养阶段,捕食能力增强。观察还发现,鲇前咽顶壁始终平直无粘膜皱褶;颌齿和咽齿为斜生尖锥状的同型齿,数量多、排列紧密,与相应的骨骼牢固地骨性固着;后咽、食道的粘膜上皮内粘液细胞极多,深层结缔组织肌肉层发达。这些构造适应于鲇的完全吞食摄食方式。胃腔小,前肠膨大、中肠粘膜上皮细胞纹状缘发达,肝脏和胰脏发育速度较快。胃的消化功能较弱,主要储存、消化场所为前肠,吸收场所在中肠。鱼苗4～6日龄下塘适宜,6～8日龄可开始诱其摄食人工饲料。     

Reproductive cycle and human chorionic gonadotropin-induced ovulation in hatchery reared Japanese catfish Silurus asotus

ABSTRACT:   The annual reproductive cycle, including the first maturity of ovarian development and plasma levels of testosterone (T) and estradiol-17β (E2), was examined in female Japanese catfish Silurus asotus reared under natural conditions. In addition, the possible period that final oocyte maturation and ovulation can be induced by human chorionic gonadotropin (hCG) injection were investigated. Results showed that female Japanese catfish matured 1 year after hatching under reared conditions. The beginning of vitellogenesis was in March and ovarian development and plasma T and E2 levels peaked in June. Thereafter, the gonadosomatic index gradually decreased to October and regression of oocytes at the tertiary yolk globule stage was observed. Female Japanese catfish could be induced to final oocyte maturation and ovulation by hCG treatment during the period from June to September. In addition, the fertilization rates were relatively high and stable during this period. These results suggest that yearling female Japanese catfish can be used as brood stock for seed production. This is the first study to investigate the annual reproductive cycle in Japanese catfish. These data will provide useful information regarding brood stock management and seed production.