漠斑牙鲆人工育苗过程中的生物饵料问题

<正>漠斑牙鲆(Paralichthys lethost igma),又称美国漠斑牙鲆、南方鲆、太平洋漠斑牙鲆,隶属鲽形目、鲆科、牙鲆亚科、牙鲆属。漠斑牙鲆属底栖鱼类,主要分布在美国的大西洋沿海地区和墨西哥湾。漠斑牙鲆肉质细嫩鲜美,具有生长速度快,抗逆性强,广温、广盐等优良生物学特性,适合于池塘养殖、网箱养殖和工厂化养殖等多种养殖方式,在肉质和生长速度及对环境的适应性等方面均优于褐牙鲆,被公认为是一种优良的养殖品种。     

苏北沿海网箱养殖牙鲆试验

近年来,牙鲆人工育苗技术的日臻完善,为牙鲆养殖发展奠定了坚实的基础。连云港市牙鲆工厂化养殖发展较快,但自然海域网箱养殖进展缓慢。为了弄清楚连云港海域几乎常年水质浑浊的条件发展牙鲆网箱养殖的可行性和经济效益,我们曾引进了14cm规格的1250尾牙鲆鱼苗进行网箱试养,当年获得成功;随后承担了市科技局下达的“网箱养殖牙鲆试验”课题,项目实施1年,取得了较好的试验效果,经济效益显著,现将网箱养殖试验工作总结如下：     

漠斑牙鲆养殖技术之一漠斑牙鲆养殖技术概要

漠斑牙鲆(Paralichthys Lethostigma)又称大西洋漠斑牙鲆、南方鲆,隶属硬骨鱼纲(Osteicthys)、鲽形目(Peuronetiformes)、鲽亚目(Plenronectoides)、鲆科(Bothidae)、牙鲆亚科(Paralichthyinae)、牙鲆属(Paralichthys),为深海底栖鱼类,是美洲众多鲆鲽鱼类中个体最大的一种.漠斑牙鲆具有很好的养殖性能,具有生长快、品质优、适应性广、抗逆能力强等特点,它既可生活在海水里,又可在淡水中生长,适合在我国北方、南方进行池塘养殖、网箱养殖和工厂化养殖,该品种的引进,为我国鱼类养殖又增添了一个新的优良品种.     

牙鲆Paralichthys olivaceus(Temmincket Schlegel)的养殖技术

牙鲆是我国海水鱼养殖的重要对象。本文扼要介绍牙鲆室内水泥池养殖、牙鲆网箱养殖技术等内容，对生产单位有一定的参考价值。     

牙鲆养殖技术之二漠斑牙鲆苗种繁育技术

漠斑牙鲆(Paralichthys Lethostigma)又称大西洋漠斑牙鲆、南方鲆,为深海底栖鱼类,分布于美国北卡莱罗纳州到佛罗里达州海湾及得克萨斯州南部海峡沿岸。是美洲众多鲆鲽鱼类中个体最大的一种。具有生长快、品质优、适盐范围广、抗逆能力强等特点,适宜在我国北方、南方进行池塘、网箱和工厂化等多种模式的养殖。     

牙鲆腹水病的危害及防治

目前牙鲆养殖规模正日益扩大,逐渐成为我国北方地区陆上海水工厂化养殖和海水网箱养殖最主要的养殖品种。但随着养殖规模的不断扩大,各种疾病开始频繁发生,给牙鲆的养殖造成了巨大危害,其中以牙鲆腹水病的危害最为严重。2002年我国北方各牙鲆养殖厂,无论是陆上工厂化养殖还是网箱养殖,从牙鲆苗种(5～6mm)开始一直到秋冬季200～400g／尾的成鱼均深受其害。     

牙鲆北方池塘养殖技术

牙鲆(Paralichthys olivaceus)人工养殖在英、日、韩等国已经研究多年,并获得成功的养殖经验。我国的牙鲆养殖主要是工厂化养殖和网箱养殖。目前山东省、河北省和辽宁省都有较大规模的工厂化养殖场。但是工厂化养殖和网箱养殖的一次性投资成本大,资金回收速度慢,还受海区条件的     

漠斑牙鲆内陆淡水池塘网箱养殖试验

通过内陆淡水池塘网箱养殖漠斑牙鲆试验,探索出内陆淡水池塘漠斑牙鲆网箱养殖的模式,总结出养殖过程中应采取的技术措施,25m2网箱总产漠斑牙鲆102.9kg,平均单产4.12kg/m2,漠斑牙鲆平均规格为306.25g/尾,成活率达84%,使池塘产量比往年养殖产量增加5.94%。     

池塘网箱漠斑牙鲆套养项目通过专家鉴定

近日,由河口区海洋与渔业局承担的《半咸水南美白对虾养殖池塘高效综合利用———网箱漠斑牙鲆养殖技术试验》科研项目,通过专家鉴定,该项目综合研究达到国内领先水平。项目实施两年,共开发推广南美白对虾与漠斑牙鲆套养面积250亩,漠斑牙鲆养殖网箱(3m×3m)100个,鱼虾总产84.3t,漠斑牙鲆网箱平均单产11.2kg/m2,实现产值379.6万元,效益215.7万元,辐射带动养殖面积1 000亩,实现产值1 500万元,经济和社会效益显著。项目根据黄河三角洲地区荒碱地资源优势和养殖现状,首次在国内利用半咸水南美白对虾养殖池塘进行网箱漠斑牙鲆养殖,取得成功,并总…     

盐碱地低盐水池塘网箱套养漠斑牙鲆技术研究

根据漠斑牙鲆(Paralichthys lethostigma)适广温、广盐和较强的抗逆性等优良生态习性,采用地下卤水、盐碱地渗水,通过合理淡水配兑使其适合漠斑牙鲆生理生长需求,在我国中纬度地区利用盐碱地低盐水养殖过洋、暖温性漠斑牙鲆。2004-2005年,利用盐碱地低盐水池塘虾池设置网箱套养漠斑牙鲆349.5m2,产鱼3.749t,产虾55.065t,其中2005年虾池设置网箱套养漠斑牙鲆306m2,产鱼3.245t,平均10.6kg/m2,平均全长34.0cm,体重527.4g,养殖成活率为90.5%,产虾49.003t,平均408.4kg/亩,平均规格11.9cm,养殖成活率为71.23%。虾池设置网箱套养漠斑牙鲆,可充分利用水体空间,促使池塘高产高效,提高养殖经济效益。     

港湾海域新型网箱养鲍新技术探讨

根据鲍的生活习性,总结国内外养鲍设施特点,自行研发新型竖排式网箱。通过在港湾海域进行新型竖排式网箱的养鲍试验,对养鲍过程中网箱内饵料分布、附着生物情况进行研究,并与传统挂笼养殖模式对比分析。结果表明:新型网箱养殖过程中采用平潮点倾倒法投喂龙须菜或海带,鲍匍匐基内的饵料占比分别为:龙须菜约30.4%,海带约36.7%,均高于其它投喂方式。经过9个月的养殖,网目为1 cm的竖排网箱中的鲍最终体重为(29.1±6.17)g,存活率为60.5%,传统挂笼中鲍体重为(22.8±7.93)g,存活率为33.5%,新型网箱养殖效果显著优于传统挂笼(P0.05);不同网衣规格的网箱表面附着生物附着量无显著性差异(P0.05),但均显著大于传统挂笼组(P0.05),进入夏季后,网箱中附着生物的生物量和丰富度都有显著增加。与传统挂笼相比,新型竖排式网箱具有水体交换好、操作简单、节省劳力、存活率高等优点。     

湾外海域不同结构鲍匍匐基初步对比试验

2016年3月6日—5月3日,在福建省漳浦县霞美镇浮头湾外海域进行三种不同结构鲍匍匐基养殖对比试验。三种鲍匍匐基分别为扣箱式(有效匍匐面积1.072 8 m2)、双层斜板式(有效匍匐面积1.993 5 m2)和传统养殖盆(有效匍匐面积0.413 3 m2),试验对象为皱纹盘鲍杂交鲍(Haliotis discus hanai)。试验结果如下:1)扣箱式鲍壳长日增长为0.131mm,日增重为0.129 g,存活率为98.44%,饲料转化率为3.38%;2)双层斜板式鲍壳长日增长为0.098 mm,日增重为0.096 g,存活率为99.38%,饲料转化率为4.29%;3)传统养殖盆式鲍壳长日增长为0.115 mm,日增重为0.103 g,存活率为98.00%,饲料转化率为5.37%。试验设施未受到湾外海况影响破坏。结果表明扣箱式鲍匍匐基整体性能较好,基于该匍匐基的鲍养殖网箱在经济型吊杆辅助作业下具有养殖效率高、抗风浪流性好、劳动强度低、所需劳动力少等优点,适合应用于湾外养殖。     

The cause of death of juvenile Pacific bluefin tuna (Thunnus orientalis) reared in sea net cages

Although the survival rate of juvenile Pacific bluefin tuna Thunnus orientalis (PBT) during 30 days after stocking in sea net cages has been as low as approximately 50%, the reason for this high mortality is not clear. The dead fish were collected and counted during 30 days after stocking in a sea net cage, and the growth performance, stomach contents, and bone injury were investigated. Nearly half (47.9%) had died within the first 4 days. The total length and body weight of the dead fish were significantly smaller than those of the live fish, and the weight of the dead fish did not increase during the first 7 days. Approximately one-third of the dead fish (21.9–42.9% per day) had ingested inorganic matter such as wood or Styrofoam waste during the first 7 days, and 25.0–45.0% of the dead fish sampled per day showed poor growth. The daily ingestion rate of inorganic matter decreased dramatically from the eighth day, when the daily mortality rate decreased. The percentage of dead fish with bone injuries due to collision or contact was low (less than 15%). These results suggest that one of the causes of high mortality during several days after stocking in a sea cage was accidental ingestion of inorganic matter by juvenile PBT. Improvement in feeding method can increase the survival rate of juveniles in sea net cages.     

Assessment of the removal efficiency of fish farm effluents by grey mullets: a nutritional approach

A field study was carried out to assess the use of the bottom‐feeding grey mullet (Mugil cephalus) within benthic enclosures as a means to reduce the benthic impacts of a net cage fish farm in the Gulf of Aqaba, Red Sea. Five experimental 1‐m³ net‐cage enclosures were stocked with 12 grey mullets each (fish weights 50, 70 or 144 g). The enclosures had no bottom and the mullets had access to the enclosed organically enriched sediments and to particulate matter (PM) falling from the overlying cages. Sediment traps were used to quantify and qualify the PM falling from the fish farm to the sea floor. Simultaneously, a feeding trial was performed with mullets (50 and 70 g) in experimental tanks. In order to estimate the potential growth rate and to quantify energy and protein requirements, the fish were fed a formulated diet with known composition. After approximately 70 days at sea, mullets in the enclosures had used up all the available food in the sediment and gained up to 0.78 g day^?1 fish^?1. Applying the values for energy and protein requirements for maintenance and growth derived from the experimental trial, estimates indicated that the grey mullets effectively removed 4.2 g organic carbon, 0.70 g nitrogen and 7.5 mg phosphorus kg^?1 mullet m^?2 day^?1 from the organically enriched sediment. Thus deployment of grey mullets may be an efficient means to improve the quality of sediments below intensive net‐cage fish farms.     

Technological solutions and operational measures to prevent escapes of Atlantic cod (Gadus morhua) from sea cages

Escapes of cod (Gadus morhua) from sea cages represent an economic problem for farmers and a potential environmental problem. We estimate that 0–6% of cod held in sea‐cage farms in Norway were reported to have escaped each year from 2000 to 2005, which is a high proportion compared with salmon. We interviewed employees at 19 coastal sea‐cage cod farms in Norway to investigate both how and why cultured cod escape and to document cage handling and management strategies that were effective in minimizing escapes. Based on the interviews, we describe five working hypotheses that may explain why a greater proportion of cod than salmon escape: (1) cod are more willing to escape than salmon; (2) cod bite the net cage and create wear and tear; (3) net cages have insufficient technical standards for cod culture; (4) cod are placed in sea cages at considerably smaller sizes than salmon; and (5) cod are more popular feed for predators. Preliminary testing of the hypothesis that cod bite netting and create holes was done by placing pre‐damaged net panels with cut twines and control panels inside sea cages. Holes in the pre‐damaged net panels increased in size over a period of 3 months. The type of damage indicated that biting of netting twines was the likely cause.     

深水网箱养殖中的声学监测问题探讨

针对深水网箱养殖过程出现的一些诸如网衣安全、鱼类逃逸等问题,介绍了几种类型的监测技术应用:(1)声学警戒带方式构成的被动式网衣安全监测技术,监视声纳可以是单波束,也可以是机械扫描的多波束或电子扫描的多波束,同时采用水下机器人进行巡视;(2)基于网箱中鱼的目标强度,实现对网箱中养殖品种大小、数量的统计监测,鱼的目标强度主要取决于鱼的体态特征,同时也与发射声波的波长有关;(3)数量识别技术以及饵料投饲过程中的声学监测技术,通过将声纳输出信号反馈到投饵机,实现饵料投放自动化。     

Examination of net volume reduction of gravity-type open-net fish cages under sea currents

Owing to heavy criticisms of nearshore fish farming for causing environmental pollution and encroaching on sea space used for shipping, boating, recreational sea activities and marine eco-tourism, offshore fish farming has now being seriously considered. Moreover an offshore site provides more pristine water and greater space for increased fish production. However, offshore fish farming poses challenges such as a more energetic sea environment. A higher sea current can lead to large deformation of fish net and hence a net volume reduction which compromises fish welfare. With the view to identifying the effects of various important parameters on net volume reduction of a gravity-type open-net fish cage, this paper adopts a mass-spring model for the dynamic analysis of current-induced net deformations of cylindrical fish nets with discrete weights hanging at the bottom edge of the nets. In this model, the net mesh comprises knot nodes and bar nodes connected by tension-only massless springs. The spring stiffness is determined from the net bar diameters and material properties. The current-induced loads are applied to each node and calculated based on Morrison’s equation. The governing equation system for nodal motions can be established according to Newton’s second law, and solved by using the Runge-Kutta method for the real-time net deformations. The effects of net string reinforcements, weight distributions and net shapes on the net volume reduction are studied with the view to shed insights into how one may improve fish cage designs to effectively mitigate net deformation under high sea current speeds in offshore fish farming sites.     

海水网箱养殖长鳍篮子鱼的摄食与生长特性

于2005年10月至2006年5月对海水网箱养殖长鳍篮子鱼(Siganus canaliculatus)的摄食与生长特性进行了研究。结果表明,长鳍篮子鱼主要栖息于水体中下层,喜结群,易受惊,活动能力较强,具有争抢食物的习性,喜摄食网衣上附着的藻类。初始体重17.8±3.2 g的长鳍篮子鱼经187 d养殖,平均体重达68.4 g,日均增重0.27 g,平均瞬时增重率为0.72%。长鳍篮子鱼的生长速度受水温影响明显,采样阶段平均水温23.0℃时瞬时增重率达到最高值2.10%,当水温降到16.0℃以下时,瞬时增重率出现最低值0.22%。长鳍篮子鱼的全长与体长呈线性关系,相关方程式为:LT=0.7228LB+5.6424;体长与体重呈幂函数关系,相关方程式为:W=0.00002L3.0559,其生长属于等速生长类型。     

围网与普通网箱养殖大黄鱼营养成分的比较与分析

大黄鱼Larimichth ys crocea (Richardson)是我国重要的海洋经济鱼类,传统养殖的大黄鱼肉质已明显不如野生大黄鱼.本实验采用临近海区不同的养殖模式(围网与普通网箱)养殖的大黄鱼肌肉来研究其营养成分(包括常规营养成分和游离氨基酸)的含量与营养评价.结果表明:围网养殖大黄鱼的粗蛋白、氨基酸总量、呈...     

Survival, growth and feeding of Atlantic salmon, Salmo salar L., smolts after transfer to sea water in relation to the failed smolt syndrome

Abstract. An increase in mortalities, due to the failure of some smolts to feed after transfer to sea cages, has been observed in many fish farms during the last 2 years. In the present study mortalities were as high as 9–5% and the majority of these appeared 7–9 weeks post-transfer. Comparisons of length-weight relationships between the initial group of smolts released in the cage and at 3-, 6- and 8-wcek intervals after transfer showed that a proportion of the fish had lost weight. The condition factor of individually measured fish also confirmed that with increasing time after transfer some fish were in a much poorer condition.
The feeding of smolts after transfer was not related to their size. The fork length distribution of feeding and non-feeding fish showed that feeding fish were recruited from all size classes of the initial population.
The lack of appetite in smolts after transfer was demonstrated by the reduced number of fish feeding and by the amount of food consumed. In the first week after transfer only 10% of the fish were feeding in the sea cage, increasing to 65% after 5 weeks. In the tanks (where there were no failed smolts) 95% of the smolts were feeding within 5 weeks after transfer, whereas in the sea cage it took 8 weeks before this figure was reached.