浙江南部近岸水域海蜇放流增殖研究

１９９２－１９９４年,每年４－５月浙江苍南县近岸水域进行海蜇苗放流增殖,放汉回捕率为０．５７－２．３３％,停止放流后的１９９５－１９９７年在浙南近岸水域共捕到海蜇１２４．２万只,,放流结果表明,海蜇放流回捕率是高的,并且出现了自然繁殖群。     

塔岛湾海蜇生产性增殖试验

为恢复海蜇资源,山东省于1991年在渤海莱州湾首次进行海蜇人工放流增殖试验研究,并于1994年将其列为生产性增殖品种在莱州湾进行了大规模的人工放流,回捕率在1．12％～3．32％之间,取得了显著经济、社会和生态效益。为进一步扩大海蜇增殖规模和数量,我们于2003～2004年在山东黄海南部的塔岛湾进行了海蜇生产性增殖试验。     

莱州湾海蜇放流增殖的回捕率和效益分析

本文报道了在以幼蜇伞径大小异来区分放流幼蜇与自然幼蜇的方法是可行的基础上，用二年来调查回捕结果，验证了莱州年生产数量中，放流海蜇数量所占百分比基本与回捕结果一致，为了使海蜇放流增殖的回捕率留有余地，综合分析认为：莱州湾海蜇放流增殖的回捕率估计为０．５－１是妥当的，其经济效益，社会效益和生态效益也是巨大的。     

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。     

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。     

海蛰大规格苗种培育技术

近年来我国已大规模开展海蜇生产性放流增殖和池塘人工养殖工作,并已取得了较好的成果。然而不论放流增殖还是池塘养殖都存在放苗量多,回捕率低的问题。据统计放流的回捕率低于1%,而池塘养殖回捕率也不高,据介绍最高的只有25%～30%,低的仅有2%～3%,平均不足10%。海蛰的敌害极少     

海蜇增殖放流效益显著

描述了在胶州湾进行海蜇的增殖放流情况，调查统计显示，海蜇的回捕率达到2％，投入产出比为1：6．8，放流投资利润率520％，对渔业资源的恢复及渔业经济的增殖具有重要的现实意义。     

江河渔业资源增殖技术研究报告

本研究采用人工放流鱼苗,加强护养管理的方法增殖江河渔业资源,从1991至1994年累计放流草、鲤、露斯塔野鲮等鱼苗195万尾,放流后4年的平均产量比放流前5年的平均产量增加5倍.本研究用标志回捕法研究增殖后鱼类回捕率、生长速率和种群数量,用放流前后多年平均产量对比法估算增殖产量.回捕率在14.5%—20.5%,平均年增殖产量146吨.     

报刊文萃

<正> 浙南沿海海蜇资源从70年代后期开始几乎绝迹,为了恢复海蜇资源,浙江省海洋水产研究所在温岭县境内的乐清湾江厦港自然海区,进行海蜇人工放流增殖和回捕小型试验。于5月上旬投放了10万颗人工培育的幼海蜇。这项试验将为人工培育的海蜇在台州地区安家落     

对浙南近岸水域停止海蜇放流后的海蜇调查

<正> 辽宁省海洋水产研究所在黄海北部近岸水域,山东省海洋水产研究所在山东莱州湾近岸水域都进行了数年的海蜇放流增殖研究,放流当年的回捕效果明显。但未见到有出现自然繁殖群的报道。本文对1992～1994年在浙南近岸水域进行海蜇放流增殖后于1995～1997年连续三年出现的自然繁殖群的调查结果进行了报道。     

夏初辽东湾海蜇放流区大型水母和主要浮游动物

根据2005～2007年6月上旬和7月上旬在辽东湾海蜇放流区进行的大型水母调查及同期进行的浮游生物调查数据,分析了该区域大型水母及浮游动物的数量分布特点以及海区中浮游动物的生态类型和优势种,并且试图寻找浮游动物的数量分布与大型水母的数量分布的关系。结果表明,浮游动物的优势种为小型桡足类及桡足类幼体:双刺纺锤水蚤Acartia bifilosa、小拟哲水蚤Pa-racalanus parvus、强额拟哲水蚤Paracalanus crassirostris、桡足类幼体、无节幼体。大型水母主要有:海蜇Rhopilema esculentum、沙蜇Nemopilema nomurai、白色霞水母Cyanea nozakii。大型水母的高密集区往往位于浮游动物高丰度区的附近。     

超声波优化辅助盐渍海蜇脱铝工艺

为探究超声波辅助盐渍海蜇脱铝工艺的条件,实验以盐渍海蜇为原料,采用电感耦合等离子体质谱法（ICP-MS）进行检测,其铝残留量为考察指标,通过单因素实验研究复合保鲜液浓度、超声功率、超声频率以及超声时间对盐渍海蜇脱铝效果的影响,根据Box-Behnken中心组合实验设计,采用响应面分析法分别优化复合保鲜液脱铝工艺与超声波辅助脱铝工艺。结果显示,未超声波辅助处理的优化条件：料液比1∶7（g/mL）、浸泡时间4 h、浸泡次数3次,铝残留量最低为126.4 mg/kg,浸泡时间影响最为显著;超声波辅助处理影响脱铝率大小的因素依次为超声时间 > 超声功率 > 超声频率 > 复合保鲜液浓度;其最佳工艺：超声频率28 kHz、超声功率272.6 W、复合保鲜液[V（醋酸）∶m（丙酸钙）=1∶2]浓度0.68%、脱除时间35 min,铝残留量为124.46 mg/kg,脱铝率达到85.3%;验证实验得到实际脱铝率为82.1%,与理论预测值相比,其相对误差约为3.2%。研究表明,与未超声波辅助相比,铝脱除率稳定,脱除时间由12 h缩短至1.75 h,工艺效率提高6.9倍。因此,超声波技术应用到海蜇产业将为高效开发低铝盐渍海蜇制品提供理论依据。     

东海区夏、秋季大型水母分布区渔业资源特征分析

本文根据1999～2004年的夏季和秋季东海区大型水母和渔业资源的状况,分析了大型水母分布区内的渔业资源特征。结果表明大型水母夏季主要分布于30°30′～33°00′N间,秋季主要分布于32°00′N以北海域,并呈现由夏季到秋季逐渐往北转移的趋势;2003年是大型水母数量最高的年份,该年水母主要分布区内的渔业资源种类数最少,CPUE最低,Margalef种类丰富度指数也最低;2003年夏季水母高发区内渔获种类的优势度也较其它年份发生了显著变化,优势种变为黄;2003年水母高发区内带鱼、小黄鱼和银鲳的当龄鱼较少,银鲳的肥满度增加,小黄鱼的肥满度降低,而带鱼的肥满度未发生显著变化。本文对水母高发区内渔业资源变化的原因进行了初步解释,并对水母的防治措施提出了初步的建议。     

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.     

Juveniles of threadsail filefish, <Emphasis Type="Italic">Stephanolepis cirrhifer</Emphasis>, can survive and grow by feeding on moon jellyfish <Emphasis Type="Italic">Aurelia aurita</Emphasis>

We conducted feeding experiments on threadsail filefish Stephanolepis cirrhifer juveniles for 16 days to evaluate the efficacy of moon jellyfish Aurelia aurita as a prey item. Four treatments, each with 40 individuals, were prepared to compare fish growth performance. The treatments consisted of filefish that were starved (control) (S), fed only jellyfish (J), fed only krill (K), and fed both jellyfish and krill (JK). Fish in the S treatment exhibited a 50% mortality rate and reduced body weight, whereas the J treatment exhibited a zero mortality rate and increased body weight. Fish in the JK treatments showed a significantly faster growth than those in the K treatment. Filefish consumed as much as 24 and 13 times their own body weight in jellyfish per day in the J and JK treatments, respectively. This is the first report showing that growth can be sustained by feeding a marine fish only jellyfish, and indicates the potential of jellyfish as a fish prey in both nature and captivity.     

Efficacy of feeding tiger puffer Takifugu rubripes on moon jellyfish with respect to nutritional composition and behavioural traits

Although jellyfish blooms are serious nuisances for fisheries and other industries, the utilization and nutritional value of by‐catch jellyfish has drawn public attention. Here, we evaluated the efficacy of feeding tiger puffer Takifugu rubripes with moon jellyfish Aurelia sp. using 20‐day rearing experiments. Feeding on jellyfish had no positive effect on growth performance, although it significantly reduced neutral lipids and increased proportions of polar lipids, n?3 and n?6 highly unsaturated fatty acids (HUFAs), especially arachidonic and docosahexaenoic acids, and taurine. Supplemental feeding on jellyfish plus pellets elevated activity and responsiveness in the fish, with no effect on burst swimming speed or prevention of aggressive biting by siblings. The present research suggests that feeding on jellyfish improves body composition and some behaviours in tiger puffers. As cultured fish tend to accumulate excessive amounts of lipids from lipid‐rich pellets that can induce an unhealthy condition, and behavioural deficits of hatchery‐reared fish reduce survival after release in the wild, we propose the use of jellyfish as a supplemental diet in the nursery production of tiger puffer. Moreover, feeding on jellyfish can overcome deficiencies in alternative soy‐material feeds by supplying phospholipid, HUFAs, or taurine.     

Estimating the economic damage caused by jellyfish to fisheries in Korea

Jellyfish cause a range of problems: they sting beach vacationers in the summer, block nuclear power plant intakes (thus disrupting the supply of electricity), decrease fishery catches, cause fishing activities to be delayed, decrease product value, and damage fishing gear. This study gauged the types and amount of damage directly caused by jellyfish. Using jellyfish monitoring data, the decreases in catch and product value for each fishery type as well as the estimated damage to each fishery type caused by jellyfish were evaluated. The results showed that the decrease in catch ranged between 6.5 and 33.7?%, and the decrease in product value ranged between 6.8 and 25.3?%, depending on fishery type. The annual direct damage caused by jellyfish was estimated to be between US$ 68.2 million and US$ 204.6 million. This corresponds to a minimum of 2.1?% and a maximum of 25?% of the annual production value, demonstrating that jellyfish cause considerable damage to the fishing industry.     

张网渔具霞水母兼捕减少装置的初步研究

近年来,霞水母的旺发严重影响了东、黄海秋冬汛张网渔业。为了维持渔业生产的正常进行,利用霞水母和目标渔获物的个体大小以及行为特性的差异,通过在网囊前安装网目长度为45cm的分隔网片和释放口所组成的兼捕减少装置(BRD)来释放霞水母。根据2000年和2001年的海上试验显示,该装置能有效减少霞水母兼捕,平均释放率达91.29%;而目标种类的平均逃逸率为13.35%,其中梭子蟹、鲳鱼的逃逸率较高,分别为52.84%和33.44%,带鱼和小黄鱼的逃逸率较低,分别为5.23%和6.27%,棘头梅童鱼的逃逸率为9.14%;同时由于霞水母的释放,使得作业中的暴网事故明显减少;霞水母BRD自设计开发、试验以后,得到了广泛的运用,自2003年起,已在江苏省启东市所辖350余艘张网渔船上全面推广应用。     

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。     

黄海南部银鲳的摄食生态

本研究应用汞质量平衡模型评估了黄海南部银鲳的日摄食量,为5.87 g wet/100 g wet/d。结合1998~2000年海上声学评估获得的资源量,计算了黄海南部银鲳年饵料消耗量为4.78×105 t,食物转换效率为1.46%。根据观察食道侧囊和分析胃含物,确认水母是银鲳的食物源之一,食道侧囊能够高效碾磨水母,是银鲳重要消化器官,胃内鳞片不是银鲳摄食对象。亟需对银鲳摄食水母的生态过程进行深入研究,从而确定银鲳控制水母暴发的潜在可能性。