CE0610 Celtic Sea Herring Acoustic Survey

This survey was conducted by the Marine Institute in Autumn 2006 as part of the annual Celtic Sea Herring Acoustic Survey. The aim of an acoustic survey is to determine the relative Abundance of the target species. This information is then used to determine catch rates and management advice for the following year. In the southwest of Ireland and the Celtic Sea herring are an important commercial species. Since 2004 the acoustic survey has been carried out in October on-board the RV Celtic Explorer. The geographical confines of the annual 21 day survey has been modified in recent years to include areas to the south of the main winter spawning grounds in an effort to identify the whereabouts of winter spawning fish before the annual inshore spawning migration. The autumn 2006 survey, from 1st-21st October, covered the area from Loop Head in ICES Division VIIb in Co. Clare, and extended south along the western seaboard into the Celtic Sea, covering the main Bays and inlets in Divisions VIIj and VIIg. For biological sampling, a single pelagic midwater trawl was used. 34 trawls were carried out. All components of the catch from the trawl hauls were sorted and weighed; fish and other taxa were identified to species level. Length measurements of herring, sprat and pilchard were taken. Acoustic data were collected using the Simrad EK60 scientific echosounder. Visual marine mammal and seabird surveys were also conducted. Oceanographic data (conductivity, temperature and depth (CTD)) was collected at 38 predefined stations. The aim of an acoustic survey is to determine the relative Abundance of the target species. This information is then used to determine catch rates and management advice for the following year.本调查由爱尔兰海洋研究所（Marine Institute）于2006年秋季开展，属于年度凯尔特海鲱鱼声学调查（Celtic Sea Herring Acoustic Survey）的组成部分。声学调查的核心目标为确定目标物种的相对丰度，所得数据将用于制定次年的捕捞率与渔业管理建议。在爱尔兰西南部海域及凯尔特海，鲱鱼是极具商业价值的重要鱼种。自2004年起，该声学调查于每年10月在“凯尔特探索者号”（RV Celtic Explorer）科研船上实施。近年来，这项为期21天的年度调查的地理覆盖范围已作出调整，新增了主要冬季产卵场以南的海域，以期在年度近岸产卵洄游启动前，确定冬季产卵鲱鱼的分布区域。2006年秋季的调查于10月1日至21日开展，调查范围覆盖克莱尔郡卢普角（Loop Head）所在的国际海洋考察理事会（International Council for the Exploration of the Sea，简称ICES）第VIIb分区，并沿爱尔兰西海岸向南延伸至凯尔特海，涵盖第VIIj与VIIg分区内的主要海湾及入海口。生物采样采用单船中层拖网（pelagic midwater trawl）作业方式，本次调查共完成34次拖网作业。对每次拖网捕捞的渔获物各组分进行分拣与称重，并将鱼类及其他分类群鉴定至物种水平。对鲱鱼、西鲱及沙丁鱼进行体长测量。声学数据通过Simrad EK60科学回声测深仪采集。同步开展了海洋哺乳动物与海鸟目视调查。在38个预设站位采集了海洋学数据（电导率、温度与深度，即Conductivity, Temperature and Depth，简称CTD）。声学调查的核心目标为确定目标物种的相对丰度，所得数据将用于制定次年的捕捞率与渔业管理建议。