CE14016 Celtic Sea Herring Acoustic Survey

This survey was conducted by the Marine Institute in Autumn 2014 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 have 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 2014 survey, carried out from 06th-26th October, covered the area from Loop Head in Co. Clare (ICES Division VIIb) and extended along the western seaboard into the Celtic Sea, covering the main bays and inlets (in ICES Divisions VIIj amd VIIg). For biological sampling, a single pelagic midwater trawl was used. A total of 19 trawl hauls 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 during daylight hours. Oceanographic data (conductivity, temperature and depth (CTD)) was collected at predefined stations. The aim of the acoustic survey is to determine the relative abundance of the target species, herring. This information is then used to determine catch rates and management advice for the following year. Other objectives include collecting physical oceanography data and visual surveys for marine mammals and seabirds.本调查由爱尔兰海洋研究所（Marine Institute）于2014年秋季开展，系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，所得数据将用于核定次年的捕捞率与渔业管理建议。 在爱尔兰西南部海域与凯尔特海区域，鲱鱼为重要的商业捕捞物种。自2004年起，该声学调查于每年10月在“凯尔特探险家号”（RV Celtic Explorer）科考船上实施。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，明确冬季产卵鲱鱼的分布位置。 2014年的调查于10月6日至26日开展，覆盖范围起自克莱尔郡（Co. Clare）的卢普角（Loop Head，国际海洋考察理事会（ICES）分区VIIb），沿爱尔兰西海岸延伸至凯尔特海，涵盖主要海湾与近岸水域（对应ICES分区VIIj与VIIg）。 生物采样环节采用单层中层拖网完成，本次调查共计开展19次拖网作业。对拖网捕获的所有渔获组分进行分拣分类与称重，将鱼类及其他类群鉴定至物种水平，并测量鲱鱼、西鲱与沙丁鱼的体长。声学数据通过Simrad EK60科学回声仪采集。调查期间于日间开展了海洋哺乳动物与海鸟的目视调查。在预设站位采集了电导率、温度与深度（CTD）海洋学数据。本声学调查的核心目标为确定目标物种——鲱鱼的相对丰度，所得数据将用于核定次年的捕捞率与渔业管理建议。 本次调查的其他目标还包括采集物理海洋学数据，以及开展海洋哺乳动物与海鸟的目视调查。