大型水母声学观测与评估技术研究进展

20世纪末以来,世界多个海域频繁出现大型水母暴发现象,对海洋生态系统、海洋渔业、沿海工业和滨海旅游业带来了巨大的灾难。为了研究大型水母生态习性,进而揭示其暴发机理并进行灾害的预警防治,近些年来国内外学者开展了大量的采用网具、目视、水下摄像、声学技术、航空影像等多种手段的大型水母监测调查工作,其中使用声学技术对大型水母进行资源评估和行为跟踪目前在欧美、日本、韩国等渔业发达国家已经开展了相关应用,在资源评估、运动学规律等研究中展现出较好的观测效果和应用潜力。目前我国在大型水母声学观测研究应用领域鲜有文献报道,通过介绍国际上利用声学技术对大型水母进行资源调查与评估、空间分布监测、运动规律等研究成果,为今后我国开展大型水母声学调查研究提供理论基础和科学依据。通过本文的分析,建议可以借鉴国际上采用科学鱼探仪、高分辨率成像声呐、声学信标等方法对大型水母进行监测调查和资源评估的研究成果,结合实际情况将声学技术逐步研究并应用到我国大型水母资源调查与评估、自然生态习性研究、重点水域大型水母动态监测预警中去,完善我国大型水母监测调查体系。

Review of acoustic techniques in the monitoring and assessment of the giant jellyfish

Since the end of the 20th century, giant jellyfish blooms have occurred on a nearly annual basis around the globe and have had disastrous effects on the ecology of marine systems, fishery resources, coastal industries, and coastal tourism. Researchers, both domestically and abroad, have thoroughly investigated this phenomenon using nets, visual observations, underwater cameras, acoustic technology, and aerial imagery, among other techniques to elucidate the underlying mechanisms of these blooms. In recent years, acoustic technology has been used to investigate cultured giant jellyfish stock and their behavior in fisheries in Europe, the United States, Japan, and Korea. These technologies have demonstrated favorable monitoring capabilities and the potential for their application in both resource assessment and the kinematics of the species. Until very recently, studies using acoustic monitoring to investigate giant jellyfish were still lacking in China. In this study, we introduce research regarding the acoustic assessment, spatial distribution, and behavioral acoustic telemetry of giant jellyfish to provide a theoretical and scientific basis for the use of acoustic technology for their monitoring and assessment in China. The acoustic target strength of jellyfish is much lower than that of fish because of the lower reflectivity of the jellyfish as a result of its high water content (> 95%). However, it is clear now that many species of giant jellyfish are able to produce significant sound scattering at frequencies routinely employed for fisheries assessments. Several studies have shown that the acoustic target strength of giant jellyfish has a positive relationship with its bell diameter. Acoustic monitoring and assessment of giant jellyfish have been more effectively conducted in regions with a dominance of the cnidarian, and in most cases, a combination of nets or video images and other methods were used. Because of the favorable application of a scientific echosounder, high resolution imaging sonar, and ultrasonic pinger in the acoustic monitoring and assessment of giant jellyfish internationally, we recommend their use in China as well. Several suggestions are proposed to support the use and further development of acoustic technology for the study and assessment of the giant jellyfish, including studies of ecological behavior, monitoring, and forecasting and warning systems in key coastal areas to improve the current monitoring systems for giant jellyfish in China.