我国深水网箱养殖技术及发展展望（上）

深水抗风浪网箱代表着海水网箱养殖的发展方向,是国家今后重点支持的先进的海水养殖方式。为此本刊特邀国内著名的深水网箱养殖专家徐君卓教授就我国深水网箱的发展现状、养殖技术、挪威深水网箱发展情况等内容作一介绍,刊出后收到了很好的效果,很多读者纷纷来电、来函询问深水网箱的有关问题,并希望我刊能多刊登这方面的文章。我刊又邀中国水产科学研究院南海水产研究所深水网箱课题组负责人郭根喜研究员等专家重点就南海区深水网箱发展概况、深水网箱养殖适宜的养殖水域条件、深水网箱养殖技术及今后的发展前景作一系统介绍。     

我国深水网箱养殖产业化发展存在的问题与基本对策

深水网箱养殖在我国起步较晚。自1999年起，海南率先在国内引进国外的第一套深水网箱养殖后，以其高效益高性能在全国沿海省市展开了深水网箱国产化研制的热潮。2001年，由中国水产科学研究院南海水产研究所主持的”十五”国家科技攻关计划。在广东省科技斤及广东省海洋与渔业局的联合资助下，成功研制出我国第一套具有自主知识产权的“HDPE园形双浮升降式深水抗风浪网箱”，单位水体产鱼14kg。据不完全统计，截止2004年底。全国有深水网箱达2700多只，养殖水体达351万立方米，理论产量可达49140吨。随着深水网箱急速的发展，带来的问题也逐渐显现，养殖系统一次性投资较大，产业配套不完善包括深水网箱的配套设旋、养殖技术与主养品种、养殖布局与养殖容量、饲料与病害防治、产品加工与流通在内，直接制约了深水网箱的发展，结果是导致深水网箱养殖设施空置率偏高，达1／3强。解决深水网箱养殖产业化发展存在的问题，首先实施深水网箱高技术集成，完成养殖产业链（群）的连接，建立全新养殖模式，与渔业产业结构性调整的政策性衔接，是深水网箱产业化的重要研究课题。     

海水网箱养殖现状及抗风浪网箱养殖的发展前景

报道了中国与广东省海水网箱养殖的现状及存在问题，介绍了深水抗风浪网箱的特点及国外深水抗风浪风猜想垢主要，描述了广东深水抗风浪网箱养殖的发展前景。     

深水网箱的发展现状与方向

本文阐述了国内外深水网箱的发展现状。并对深水网箱进行了新的分类,介绍了国外水流对 网箱影响的研究成果,最后提出了深水网箱的发展方向。     

立足市场办基地 依靠管理创效益

深水抗风浪网箱养殖是海水鱼类养殖发展的方向，近年来在各级政府的支持下海水抗风浪网箱养殖发展很快，全国已有深水抗风浪网箱3000多个，广东、海南、福建、浙江省都有一批深水抗风浪网箱养殖基地，自主创新的网箱制作取得了专利，投放的网箱经受了强台风的袭击，黄花鱼、军曹鱼、金鲳鱼、鲱鱼等鱼类在深水网箱中养殖也己成功，并创造了高产记录。     

海水经济鱼类深水网箱养殖新技术

大型深水网箱养殖，形式多种多样，是近年来国际上发展迅速的离岸型网箱养殖新技术。深水网箱一般由海底固定、网箱框架、高强度网箱、养殖配套设施等组成，是科技含量较高的海水鱼类养殖方式。深水网箱养殖具有集约化程度高、养殖密度大、单位水体产量高、产品质量高、经济效益显著、抗风浪能力强，可在半开放海区养殖等     

深水抗风浪网箱的应用与改进

嵊泗县绿华岛具有良好的海洋生态环境。蓝海洋公司自2000年开始进行深水抗风浪网箱养殖生产，先后使用了浮绳式网箱、圆形网箱、金属网箱、飞碟形网箱。在实际应用的过程中获得了丰富的技术数据和生产经验，也碰到了一系列问题和困难。在对这四类网箱进行生产应用的基础上，分析其中存在的问题和不足，介绍了一些问题解决的基本方法，并提出了进一步发展的设想。     

大型抗风浪深水网箱养鱼发展现状与趋势

大型抗风浪深水网箱是一种全新的养殖方式与设备，它与充分采用了当代的计算机，新材料、防腐蚀、防污染、抗紫外线等高新技术，推广深水网箱养鱼是向海洋要食物，发展海洋经济的一条有效途径，它可为城乡人们提供鲜活名特优水产品，市场前景广阔，社会经济效益显著，作者就大型抗风浪深水网箱养鱼发燕尾服现状与趋势作扼要概述。     

平潭县推广深水抗风浪网箱养殖的现状、问题及对策

福建省平潭县是个岛县，四面环海，海岸线较长，20m等深线以上未开发的可养水面广阔。自2001年开始，该县作为全省重点大型抗风浪网箱示范县，经近几年试验性生产，取得明显成效，现已发展到84个网箱。为使全县深水网箱养殖持续、健康发展，本文在对全县各深水网箱示范点进行广泛调查的基础上，就深水网箱现状、存在的问题以及发展对策作一粗浅的探讨。     

中国海水网箱的产业发展现状与未来发展方向

海水网箱养殖是水产养殖中一种重要模式。在当前海洋渔业资源日益衰退的形势下,海水网箱养殖成为中国水产养殖绿色可持续发展必然选择的方向之一。海水网箱的发展体现了中国在海水网箱高科技的集成,也代表着中国海水网箱养殖技术的逐步成熟。文章概述了中国普通网箱、深水网箱和深远海网箱的发展现状,着重介绍了以浮式网箱为代表的3种深水网箱,以及以“深蓝1号”全潜式深远海渔场为代表的3种深远海网箱的研究现状,并且提出建议:为符合中国水产养殖绿色发展的要求,海水网箱未来应沿着离岸拓展化、大型升级化、智能自动化和规模集约化的方向发展。     

Gonad quality of sea urchin Paracentrotus lividus cultured in an offshore pilot‐scale trial on the south‐east Italian coast

A pilot project aimed at testing roe enhancement strategies based on offshore Paracentrotus lividus cultures was conducted off the south‐east coast of Italy (Apulia Region). Adult sea urchins were reared in sea cages located 700 m offshore at a depth of 12 m for 3 months. The animals were fed once a week on two formulated diets, prepared mixing nutrients with agar 20 g/Kg and differing only in terms of the protein source: anchovy flour (Diet A) or krill flour (Diet K). At the end of the rearing trial, the gonad somatic index of sea urchins fed on formulated diets significantly exceeded that of wild sea urchins. Total FAA content in the gonads of wild sea urchins and Diet A‐fed sea urchins was similar, whereas in Diet K‐fed sea urchins it was significantly higher. In terms of fatty acids, the gonads contained SFAs, MUFAs and PUFAs. In visual and sensory assessment of gonads by panel test and electronic nose, the gonads of reared sea urchins were rated as being of better size, while no differences were recorded for coloration, taste and odour. This study shows that under these experimental conditions, commercial‐grade Paracentrotus lividus roe enhancement can be achieved after 3 months in sea cages.     

Feasibility of Offshore Co‐culture of Abalone,Haliotis discus hannai Ino,and Sea Cucumber,Apostichopus japonicus,in a Temperate Zone

Feasibility of offshore co‐culture of abalone and sea cucumber was investigated in Northern China. Survival and growth of abalone, Haliotis discus hannai Ino, and sea cucumber, Apostichopus japonicus, co‐cultured in abalone cages from suspended longlines, in the offshore area, were examined. Abalone and sea cucumbers were co‐cultured at density ratios of both 3:1 and 6:1 for 1 yr. Abalone were fed with fresh kelp and no additional feed was given to sea cucumbers. Survival of abalone and sea cucumber was 100% for all treatments. Abalone and sea cucumber grew well; the body weight (BW) of abalone and sea cucumber was nearly doubled and had reached a commercial size. There were no significant differences in the growth rates for both abalone and sea cucumber between the two density treatments. The specific growth rate of BW of abalone (SGRbw) was highest in June, with a value of 0.536%/d. Growth rate of sea cucumber (SGRsc) was highest in December, reached 1.84%/d, with an annual average SGRsc of 0.182%/d. Results suggested that the offshore co‐culture of abalone and sea cucumber was feasible offshore. The co‐culture of abalone with sea cucumbers may provide an additional valuable crop without additional financial input.     

Strategies and technologies in offshore farming

A more restrictive attitude to inshore farming, in addition to positive biological findings among offshore farmed fish, have increased the demand for suitable offshore fish farming cages/systems.

To develop such a cage/system, the requirements of the fish, the fish farmer, the insurance companies, the authorities and the moorings must be considered. The existing offshore concepts can be classified into: (1) simple flexible one-net bag cages; (2) integrated stiff semi-submersible one-net bag constructions; (3) simple stiff poly-net bag cages; (4) integrated stiff poly-net bag constructions; (5) submersible and submerged cages. An example from each group is described.

The Bridgestone cage and the Farmocean system, the only offshore concepts that have been in commercial use for some years, are compared with respect to strength and management. The other concepts are evaluated in various parts.

A suitable offshore concept should, in general, consist of a stable, strong and safe platform that should be easy and safe to tow, moor and board. It should allow a proper attachment of the net bag (preferably round, 15 m deep and 5000 m³ in volume), and guarantee its strength and shape during all weather conditions. The fish should be fed by means of a computer-controlled automatic feeder.

Faster growth, lowered mortality and reduced visceral fat content are reported among offshore farmed fish compared with those farmed inshore. A lower degree of self-pollution will also be a consequence of moving larger and deeper cages/systems offshore.

The tentative rules for the type approval of floating fish farming units that have been presented by “Det norske Veritas” (DnV) in Norway will be positive for the fish farming business if it starts to be valid and cover the rest of the fish farming countries.

Despite the higher investment required for the offshore cages/systems, it has been indicated that there is a better economic result and that the cost of producing 1 kg of fish is lower than in conventional fish farms.

As the single-net bag concept represents a lower risk for the fish farmer, insurance company and veterinary authority, it will probably be the preferred concept.     

Improving rearing performance in sea‐cage culture of Pacific bluefin tuna Thunnus orientalis juveniles (Temminck and Schlegel) using small sea cages

High levels of mortality occur in large net‐cage culture of Pacific bluefin tuna (PBF) Thunnus orientalis due to poor growth on commencement of sea‐cage culture obstructing the mass production of fingerlings. Therefore, we carried out this study to develop a countermeasure by using small sea cages (square with 13‐m sides). PBF juveniles were directly transferred to a 30‐m‐diameter cage (control) and compared them to fish transferred to small sea cages for 12 days before being merged into another 30‐m‐diameter cage. The survival rate, growth performance and potential factors increasing mortality were examined. The results of our study showed that survival rate in small sea cages was approximately 20% higher than that of the control. Poor growth also occurred in the small sea cages; however, its frequency and daily mortality rate were half those in the control. In addition, growth performance such as specific growth rate and weight gain of PBF juveniles in small sea cages significantly increased compared to the control. These results suggest that using small sea cages could be an effective countermeasure for poor growth, which may mitigate the high‐mortality conditions of current sea‐cage culture systems for PBF.     

潜浮式船型桁架结构深海养殖网箱避浪性能研究

深海网箱作为现代海洋渔业拓展外海养殖空间的重要养殖装备，其布设环境一般较近海更为复杂恶劣，对于保障其安全性和稳定性提出了更高的要求。本研究针对一种单点系泊潜浮式船型桁架网箱开展了模型比尺为1︰40的波浪流水池试验，重点围绕该网箱在不同吃水深度受波浪作用的系泊受力、升沉、纵摇和横摇等水动力学特性进行了比较分析。试验结果显示，波高为7.5~12.5 cm时(原型3~5 m)，网箱漂浮状态即可以满足养殖需求，其系泊力及运动响应均较小，具备较高的安全性和稳定性；恶劣海况时，即本试验中波高为15.0和17.5 cm (原型6 m和7 m)，通过整体下潜的方式网箱具有良好的避浪性能，其中，系泊力减幅达70%以上，升沉、纵摇和横摇等运动分量减幅也达20%~60%；波流试验中，海流对网箱避浪性能存在一定的影响，但总体上仍然具有较好的避浪效果。研究结果可为单点系泊潜浮式深海网箱的安全运行与日常管理提供理论依据和数据参考。     

多维视角下的新时代水产养殖业发展

由于经济因素的驱动,我国水产养殖规模和集约化水平在快速扩大和提高,同时,土地、淡水和鱼粉等资源制约日趋明显,氮磷排放、碳足迹、生态足迹在迅速增大,因此,我国水产养殖业需要生态集约化发展。从多维和可持续发展的视角可以推知,内陆大水域未来仅适于发展不投饲的养殖种类或称净水渔业,近岸(10 m以浅、距岸2 km以内或有遮蔽的海域)可发展不投饵的贝、藻养殖和增殖,离岸(距岸2 km以外、水深10～50 m)应增殖、养殖并举,深远海养殖(50 m以深、高海况开放海域和12 n mile以外的专属经济区海域)大有可为,陆基池塘生态集约化改造和陆基循环水养殖的阳光工厂化改造任重道远。     

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。     

我国离岸水产养殖设施装备发展研究

随着我国人口的增多和生活水平的不断提高,人们对优质海洋食品需求也在不断增加。我国拥有近300万km2的海洋国土面积,目前还未得到充分的利用,因此拓展海洋蓝色资源的利用范围,发展离岸养殖,尤其是深远海养殖,缓解粮食安全保障压力,成为今后养殖发展的重点。而这就需要通过采用现代新技术,大力发展离岸水产养殖设施装备。文章重点介绍了"十二五"期间我国筏式养殖设施装备、网箱养殖设施装备和深远海养殖设施装备的发展状况、存在的主要问题和需求、国外发展现状等,并对今后的发展提出了建议。     

中国深远海网箱的发展现状与展望

深远海网箱养殖是一种新型水产养殖模式,具有技术先进、环境友好和成鱼品质高等优点,因此,它对推进水产养殖绿色发展战略意义重大。本文在介绍中国普通网箱和深水网箱、国外深远海网箱发展简况的基础上,重点概述2017年前后中国深远海网箱发展现状及其研究进展,并对今后的发展方向加以展望。2017年前,我国深远海网箱处于起步阶段,开发了特力夫~(TM)超大型深海养殖网箱等近10种深远海网箱。2017年后,我国深远海网箱进入快速发展期,开发应用了"深蓝1号"全潜式深海渔场等一系列深远海网箱,引领了深远海网箱的现代化建设。迄今为止,我国主要开展了深远海网箱的定义、专利、结构、绳网材料及其配套智能装备等研究,部分成果已得到应用。为适应水产养殖绿色发展要求,今后我国深远海网箱将朝着离岸化、大型化和智能化等方向发展。虽然我国深远海网箱养殖业取得了长足进展,但与挪威等国外先进技术相比,我们还存在巨大的差距。我国深远海网箱养殖业前景广阔,但相关工作任重道远。     

A closer look at closed cages: Growth and mortality rates during production of post-smolt Atlantic salmon in marine closed confinement systems

The most controversial environmental problems in commercial salmon farming are the negative effects of sea lice (Lepeoptheirus salmonis, Caligus spp.), the genetic introgression of farmed salmon in wild populations, nutrient waste load and the emission of potentially toxic waste to coastal waters. Moving production from sea cages to land-based facilities, offshore farming or marine closed containment systems (CCS) are suggested as possible ways to solve these problems. However, there are few published studies on production capacity and fish welfare in such systems. The main aim of this study was to describe growth rates, mortality rates and mortality causes in the commercial-scale production of Atlantic salmon (Salmo salar) post-smolts in CCS from sea transfer until the size of 1000 g. From October 2014 to May 2017, we recorded growth rates, feed use, mortality and mortality causes during 23 CCS production cycles, including 18 CCS periods with off-season smolt (S0) and 5 CCS periods with one-year smolt (S1). The mean (SD) growth rate, thermal growth coefficient (TGC), for all 23 CCS was 3.03 (0.34), with no difference between cages with S1 (n = 5) and cages with S0 (n = 1 8). Cumulative mortality three months after sea transfer (CM_3mo) was 2.6 %, while cumulated mortality throughout the total trial period (CM_total, mean number of days = 159) was 3.6 %. Both CM_3mo and CM_total were higher in S1 groups than in S0 groups. Mean (SD) feed conversion ratio in CCS with S0 (n = 18) was 1.11 (0.07). The two main mortality causes were ‘Ulcers and fin rot’ (S1 and S0) and ‘Failed smolt’ (S1), accounting for 36.1 % and 19.3 % of the total mortality, respectively. Water flow, oxygen saturation and other water quality parameters were within safe limits for fish health and welfare.