海蜇增养殖技术讲座（五）——山东沿海内湾海蜇放流增殖技术

自20世纪80年代以来，已对海蜇的生活史、人工育苗和放流增殖进行过不少研究，并形成了较为完善的配套技术，为今后进行海蜇生产性放流增殖提供了科学依据和实践经验。通过对莱州湾等多年的人工育苗、人工放流、回捕效果等方面研究，结合海蜇的生态习性和山东沿海的海况条件等，认为在山东沿海适亢内湾进行海蜇放流，扩大放流规模，增加放流数量是可行的。     

信息与动态

由山东省水产研究所和莱州市对虾育苗增殖场共同承担的国家“八五”技术攻关课题-海蜇人工育苗放流试验,最近,通过国家有关部门技术验收。海蜇人工育苗放流试验是利用秋季捕获的亲蜇产卵、孵化并附着越冬,春季利用越冬螅状幼体,放散蝶状幼体、育成稚蜇进行     

黄海北部大规模放流海蜇获得成功

辽宁省海洋水产研究的科研人员在揭开了海蜇生活史奥秘之后,又攻克了海蛋的人工育苗、螅状体越冬和幼蜇放流等技术的关键,并与辽宁省海洋渔业开发中心等单位合作,从1987年开始进行黄海北部海蜇幼体放流试验研究。经过5年的放流试验,使黄海北部海蜇资源逐渐增加,目前已成为继中国对虾放流增殖后的第二个增殖对象。海蜇放流的     

海蜇的人工育苗及养殖技术（二）

3 海蜇的人工养殖。早在八十年代初，国内已进行海蜇的人工育苗及放流的报道，但由于当时的条件，意识所限，以及技术方面的欠缺等等原因，海蜇没有能够形成大规模的生产。近几年，辽宁锦州、营口等地，出现个别养殖户利用天然纳潮进来的海蜇苗种进行人工养殖，获得了较大的经济效益，亩盈利均在千元以上。2000年，盘锦光合水产有限公司在辽宁省水产研究所海蜇专家陈介康研究员的指导下，对海蜇的人工育苗及养殖进行的探索和研究，首次取得了大规模培育海蜇人工育苗的技术突破。2001年培育幼蜇150万片，供应养殖面积2．8万多亩，但是由于养殖技术上的原因，养殖成功率仅在10％左右，唯一值得欣慰的是成功的养殖户其利润都非常可观，亩盈利都在千元以上。在2000年的基础上，2002年，光合公司成功培育幼蜇1500万片，供应养殖面积50多万亩，并在养殖技术上也加大了科技投入，从而积累了很多宝贵经验，使养殖成功率获得了很大的提高。     

浙江近海海蜇增殖研究

1975年后浙江南部海蜇资源突然衰退,至今20年没有恢复迹象。采用人工放流增殖方法逐步恢复资源量。全人工育苗研究已经完成,并进入工厂化、规范化育苗阶段,保证了放流种苗的供应。同时,在浙江北部完成了海蜇放流可行性的研究。利用标志放流方法计算回捕率为0.88%,在123天中,平均日生长为0.33cm。1992年,又在浙江南部进行试放流,回捕率为1.29%。人工放流海蜇在自然海区能进行自然繁殖。     

辽宁近海渔场海蜇增殖放流的回顾与发展

辽宁近海渔场海蜇放流经过1988-1993年、2004年在海洋岛渔场和2002年在辽东湾各渔场的增殖试验与2005-2006年的生产性增殖放流，探索了放流海域选择、放流时间和放流规格，跟踪监测技术，回捕效果检验等相关技术。笔者就海蜇增殖放流情况作系统回顾，并对其大规模发展做以探讨。     

海蜇全人工养殖获成功

1991年,山东省海滨城市——荣成,全人工养殖海蜇获得成功。经国内有关专家对海蜇育苗和试验养成进行验收,一致认为该项技术属水产科技领域的一项重大突破。荣成市高级工程师邱铁铠,1987年率先提出了“海蜇全人工养殖技术开发课题”,并列入了1990年国家科委重点科研计划。1991年6月,他在邱家渔业公司育苗厂的协助下,成功地用自然海区捕捞的海蜇,贮养后获得了受精卵,育出螅状体,用越冬螅状     

赴斐济国海蜇人工育苗试验

2007年5月17日～7月7日，应青岛金海丰水产有限公司邀请，笔者受山东省海洋水产研究所派遣赴斐济国进行海蜇养殖技术考察和人工育苗。从中国青岛到斐济国在长达46天的海上运输过程中，运载的500片海蜇螅状体健康，活动自如，无脱落。海蜇螅状体从中国到南太平洋斐济国的高温地区，万里长时间苗种运输成功，这是首次，为开发利用国外浅海海域资源，开展海蜇增养殖奠定了基础。     

浙南海域海蜇增殖前景的探讨

１９９２年至１９９４年在浙南海域进行了三年海蜇人工增殖工作，共放流０．３公分以上海蜇状体１７５３３万尺，在三年中共回捕到海蜇２９３万多只，三年平均回捕率达１．６７％，并且于停止放流后的１９９５年和１９９６年共捕获蜇６１厉 多只，产生了较好的社会效益和一定的经济效益。     

日本栽培渔业见阔（三）

二、育苗放流技术 作为放流或养殖用的人工苗种，有车虾、鲍、海参、银蛙、真鲷、香鱼、河豚鱼、梭子蟹、海带、紫菜等；利用海区天然苗种作为养殖或放流用的，有，蛳鱼，牡蛎和扇贝等。这次，我们没有考察到紫菜、海参和梭子蟹的育苗情况。下面将考察到比较特殊的育苗技术和放流增殖效果作简单介绍：     

莱州湾海蜇增殖放流的可行性及建议

从海蜇的生物学特点和生态习性出发，对莱州湾的温度、盐度、饵料生物、海蜇苗种来源、回捕率以及增殖放流的经济、社会和生态效益进行了分析，认为在莱州湾放流增殖海蜇是可行的，并对放流数量、规格、地点、方法和时间提出了建议。     

三种大型钵水母幼体对牙鲆和许氏平鲉仔稚鱼的捕食选择性

为探讨中国近海常见大型钵水母对鱼类资源补充的影响,本实验利用清除率法比较研究了伞径4 cm的3种大型水母幼体—海月水母(Aurelia aurita)、海蜇(Rhopilema esculentum)和沙海蜇(Nemopilema nomurai),对不同发育阶段的牙鲆(Paralichthys olivaceus)和许氏平鲉(Sebastes schlegeli)仔稚鱼的捕食量。结果表明,3种水母均可捕食牙鲆和许氏平鲉仔稚鱼,其捕食率随仔稚鱼生长而降低,其中海月水母可捕食规格15 mm牙鲆和20 mm许氏平鲉,海蜇能够捕食规格20 mm牙鲆和30 mm许氏平鲉,沙海蜇可捕食30 mm许氏平鲉;仔稚鱼密度对水母捕食率影响不显著,牙鲆的变态和底栖生活是其逃避被水母捕食的有效手段;不同水母物种对仔稚鱼的捕食效率主要与其活力相关,水母结构和毒性也是重要因素,相同规格3种水母对仔稚鱼捕食率由高到低为海蜇沙海蜇海月水母。本研究结果可为阐明水母与鱼类的动态关系,研究海洋鱼类的自然资源补充机制提供参考。     

Predation on fish larvae by moon jellyfish <Emphasis Type="Italic">Aurelia aurita</Emphasis> under low dissolved oxygen concentrations

ABSTRACT:   Laboratory experiments were conducted to test the hypothesis that low dissolved oxygen concentrations have the potential to enhance the predation rate on fish larvae by moon jellyfish Aurelia aurita which is increasing in abundance in the coastal waters of Japan. Larvae of the red sea bream Pagrus major in four size classes (2.9, 4.1, 6.2 and 8.6 mm in standard length) were used as prey in a short-term predation experiment. No change in the bell contraction rate of the jellyfish (mean bell diameter, 100.4 ± 10.2 mm) was observed at the oxygen concentrations tested (1, 2 and 4 mg/L, and air-saturated, 5.5–6.0 mg/L), suggesting a strong tolerance to a decline in the oxygen concentration. More than 80% of the 2.5 and 4.1-mm size-class larvae were predated on by the jellyfish at all oxygen concentrations during the 15-min trials in 10-L tanks. The 6.2 and 8.6-mm size-class larvae were able to escape from the jellyfish apparently due to their developed swimming ability at the two higher dissolved oxygen concentrations. There was an increase in predation on larvae of these two size classes at the two lower dissolved oxygen concentrations. Predation by moon jellyfish on fish larvae can be more intense at low dissolved oxygen concentrations that commonly occur in the coastal waters of Japan.     

Differences in the biochemical compositions of two dietary jellyfish species and their effects on the growth and survival of Ibacus novemdentatus phyllosomas

Phyllosomas (planktonic larvae) of slipper lobsters cling onto and feed on jellyfish under both natural and laboratory conditions. Phyllosomas of Ibacus novemdentatus are capable of feeding on various jellyfish species including venomous stingers; however, the range of jellyfish species capable of supporting the growth and survival of phyllosomas is unknown. Seventeen (12 for the first and five for the second trials) and 18 (13 for the first and five for the second trials) phyllosomas were fed exclusively on the jellyfish Aurelia aurita and Chrysaora pacifica, respectively. Aurelia aurita‐fed phyllosomas metamorphosed into the nisto stage (postbenthic larvae) ～54 days after hatching, whereas C. pacifica‐fed phyllosomas did not. Major nutritional compositions such as amino acids, fatty acids and minerals were compared between the two jellyfish species. The proportion of each major nutritional component was not significantly different between the two jellyfish species, suggesting that C. pacifica was not nutritionally inferior to A. aurita. Therefore, the observation that the C. pacifica‐fed phyllosomas did not metamorphose into the nisto stage was not because of major nutritional compositions but due to other factors such as the lack or excess of other minor nutrients, or the species‐specific texture of the jellyfish.     

Effects of turbidity on survival of larval ayu and red sea bream exposed to predation by jack mackerel and moon jellyfish

We conducted laboratory experiments to examine the effects of turbidity on the survival of red sea bream Pagrus major and ayu Plecoglossus altivelis altivelis larvae when exposed to either visual (jack mackerel juveniles) or tactile (moon jellyfish) predators. The experiments were conducted in 30-l tanks with three different levels of turbidity obtained by dissolving 0, 50, or 300 ppm kaolin. Predators were introduced to the experimental tanks followed by larvae of either red sea bream (mean ± standard deviation 6.1 ± 0.3 to 11.4 ± 2.1 mm standard length) or ayu (6.6 ± 0.3 and 24.4 ± 1.8 mm). When exposed to jack mackerel, the mean survival rate of larvae was significantly higher in 300 ppm treatments compared with the other turbidity levels. When exposed to moon jellyfish, however, there was a less marked difference in the survival rates among different turbidity treatments. Survival rates of ayu larvae exposed to moon jellyfish were generally lower than those of red sea bream. Our study indicates that anthropogenic increases of turbidity may increase the relative impact of jellyfish predation on fish larvae.     

日本鳗鲡仔鱼的开口饵料和行为特征

在连续多年日本鳗鲡人工繁殖实验的基础上,研究了不同饵料对日本鳗鲡仔鱼存活率的影响,并记录了仔鱼的运动特征和摄食行为。结果显示,与对照组(不投饵)相比,投喂以鲨鱼卵、磷虾提取液为基础的饵料和以鲨鱼卵、海蜇匀浆液为基础的饵料以及微绿球藻液均提高了日本鳗鲡仔鱼的存活率,仔鱼发育至柳叶鳗前期阶段;而投喂以鲨鱼卵、卤虫匀浆液为基础的饵料和以卤虫匀浆液、磷虾提取液为基础的饵料,以及轮虫、海带+龙须菜匀浆液或海蜇以及发酵鲨鱼肉,均降低日本鳗鲡仔鱼的存活率。实验同时还研究了日本鳗鲡仔鱼的主动摄食行为,摄食时仔鱼先用吻端反复多次触碰食物,然后张开下颌咬食,证实了日本鳗鲡早期仔鱼的摄食方式是触碰后咬食。     

海蜇中明矾（铝）质量分数4种测定方法的比较

铝（Al）元素在海蜇产品中以明矾的形式存在，Al在人体内累积会对健康造成危害。当前海蜇中明矾（Al）质量分数测定方法较多，各种方法的操作及检测灵敏度均存在差异。研究比较了水煮滴定法、原子吸收光谱法、比色法和酸煮滴定法4种不同方法的检测效果，对各种方法中的前处理现象差异、检测结果、检测方法的准确度和精密度及方法的可操作性等方面进行对比。结果表明，酸煮滴定法前处理只需6min，煮沸后过滤速度快，其测定结果与原子吸收光谱法的结果相近。酸煮滴定法、比色法和原子吸收光谱法回收率介于103．81％～107．60％，平均回收率为104．70％，符合分析要求。对比各种测定方法的优缺点得出，酸煮滴定法操作简便快捷、花费少，适用于生产工厂及检测机构日常检测。     

Measurement of swimming speed of giant jellyfish <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> using acoustics and visualization analysis

A species of giant jellyfish, Nemopilema nomurai, which has appeared only recently in the East China Sea, is an emerging nuisance in the northeastern region of Asia because of its extensive damage to fisheries. Until now, the biomass estimates of these jellyfish have mainly been obtained using trawl sampling and sighting survey methods. However, it is also necessary to determine the origin and diurnal migration patterns of these jellyfish. Drawbacks of the trawl sampling method are that it is effective only in estimating the density of jellyfish population distributed throughout the entire water column and requires considerable time. Another common analysis technique is the sighting method, which is effective only in the estimation of he density of jellyfish distributed in surface areas. The sighting method can determine distributions over wide areas in a short time. This method has limitations in investigating the vertical distribution and swimming behavior of jellyfishes. In our study, we utilized an echo sounding method extensively and effectively to overcome these limitations. Our method involved the use of a scientific echo sounder, acoustic camera, and conductivity-temperature-depth instrument during the drifting of a research vessel at various stations in the Yellow Sea. The acoustical method of particle tracking velocimetry (PTV) was used to analyze the swimming speed according to the vertical distribution of N. nomurai jellyfish. Results of the scientific echo sounder indicated that the jellyfish were mainly present in the water column from the surface up to a depth of 40 m. The mean swimming speed of the jellyfish was estimated as being 0.6 times the bell size (BS), with a tendency to maintain a certain speed. Further, results of a Monte Carlo simulation showed that the swimming speed was in the range of 0.46–0.89 BS. These results might be used as an index in a migration model, which may be useful to forecast the behavior and origin of the giant jellyfish entering inshore areas on a massive scale in northeastern Asia.     

魁蚶底播增殖的试验研究

魁对是一种适应性强、生态效率高的大型经济贝类。种苗投放后成活率可达99%,1年后的回捕率在50%以上;在满足魁蚶习性要求的一般条件下,选择敌害少,海底稳定性好的海区是增殖成败的关键。蟹类(如梭子蟹、日本虫寻)对种苗危害极大,并可能导致“全军覆没”的后果;种苗放流没有严格的时间要求.壳长2.0～2.5cm 可作为放流种苗的标准规格。放流1～1.5年后可达5～7cm 商品规格,增殖效果显著,适用于生产性魁蚶资源增殖放流。