Studies on jellyfish blooming in marine coastal waters : mechanisms for the population increase and technical development for the countermeasures

近海水母繁殖研究：种群增长机制及对策技术开发

• 批准号: 13480158
• 负责人: UYE Shin-ichi
• 金额: $ 10.5万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13480158/
• 关键词: Jellyfish; Mass occurrence; Ecological impact; Marine costal environment; Nuisance of jellyfish; Decomposition of jellyfish; The Inland Sea of Japan; Tokyo Bay

The moon jelly Aurelia aurita is one of the most common schyphomedusae in the world's coastal waters, and the population of this species is highly speculated to have been increasing for the last decades. In the Inland Sea of Japan, the increase of this species occurred intensively in the last 10 years, due probably to the combination of the following factors:1) increase in food supply for the jellyfish owing to eutrophication or the modification of nutrient supply2) elevation of water temperature in the winter to allow the population overwintering3) increase in the polyp attachment area owing to the modification of the water front and construction4) decrease in planktivorous fish stock size owing to overfishing.The technique to monitor the Aurelia aurita population has been established using composite airphotographs from a Cessna and groundtruthed net surveys. The monitoring in the Uwa Sea for 4 years (2000-2003) reveals that the total jellyfish biomass varies more than one order magnitude year to year, although the causes for such annual difference are not known. According to fishermen, the nuisance of jellyfish aggregation is very severe in the Inland Sea of Japan.By measuring the respiration, feeding and growth rates of Aurelia aurita, the ecological impact of the jellyfish upon the zooplankton populations has been estimated. The daily feeding pressure ranges from a few % to several hundreds % of the zooplankton biomass, depending on the density of the medusae.One of the countermeasures is to decompose the medusae using jellyfish decomposing bacteria. Several bacterial strains which are effective to the decomposition have been isolated from the Inland Sea of Japan. A preliminary test plant for the decomposition of Aurelia aurita has been established.

月冻是世界沿海水域最常见的水母之一，据高度推测，该物种的数量在过去几十年里一直在增加。在日本内海，这种水母的数量在过去10年里急剧增加，可能是由于以下因素的综合作用：1)富营养化或营养供应的改变增加了对水母的食物供应；2)冬季水温升高，使水母种群得以越冬；3)由于水边和结构的改变，水母附着面积增加；4)过度捕捞导致食浮性鱼类种群减少。对水母海4年(2000-2003年)的监测表明，水母的总生物量每年变化超过一个数量级，但其原因尚不清楚。据渔民表示，日本内海水母聚集造成的滋扰非常严重，通过测量水母的呼吸、摄食和生长速度，估计了水母对浮游动物种群的生态影响。根据水母的密度不同，每天的摄食压力从浮游动物生物量的几%到几百%不等。对策之一是用水母分解细菌来分解水母。从日本内海分离出了几株对分解有效的细菌菌株。初步建立了金龟子分解试验装置。

项目成果

Ishii, H.: "The effects of environmental light condition on strobilation in Aurelia aurita polyps"Sessile Organisms. 20. 51-54 (2003)

Ishii, H.：“环境光条件对 Aurelia aurita 息肉中颤动的影响”无柄生物。

Fukuda, Y.: "Potential dietary effect on the fatty acid composition of the common jellyfish Aurelia aurita."Marine Biology. 138. 1029-1035 (2001)

Fukuda, Y.：“饮食对普通水母 Aurelia aurita 脂肪酸组成的潜在影响。”海洋生物学。

Ishii, H: "The influence of environmental changes upon the coastal plankton ecosystems, with special reference to mass occurrence of jellyfish"Bulletin of the Plankton Society of Japan. 48. 55-61 (2001)

Ishii, H：“环境变化对沿海浮游生物生态系统的影响，特别是水母的大量出现”日本浮游生物协会通报。

Uye, S.: "Recent increase of jellyfish populations and their nuisance to fisheries in the Inland Sea of Japan."Bulletin of the Japanese Society of Fisheries Oceanography. 68. 9-19 (2004)

Uye, S.：“最近水母数量的增加及其对日本内海渔业的滋扰。”日本水产海洋学会公报。

Watanabe, T.: "In situ estimation of ephyrae liberated from polyps of Aurelia aurita using settling plates in Tokyo Bay"Hydrobiologia. 451. 247-258 (2001)

Watanabe, T.：“使用东京湾的沉降板对 Aurelia aurita 息肉中释放的碟状体进行原位估计”Hydrobiologia。