CE0714 Irish Groundfish Survey Leg 2

This survey was conducted on board the RV Celtic Explorer in 2007 by the Marine Institute (MI) as part of the annual groundfish survey to determine the distribution and abundance of commercial fish around Ireland. The Irish Groundfish Survey (IGFS) forms part of the International Bottom Trawl Survey (IBTS) programme, an international survey effort coordinated by the International Council of the Exploration of the Sea (ICES). Each year the survey, taking place in Autumn/Winter, collects demersal trawl and ancillary data in Irish waters to produce relative abundance indices for fisheries management. In particular the survey provides an index of the share of young fish in the stock, which in turn gives an indication of its spawning success. The IGFS contributes to Ireland’s international obligation to supply scientific data that support the implementation of the Common Fisheries Policy (CFP). This survey is a series of demersal sampling trawls at pre-defineds stations. The 2007 survey took place over 2 legs. Leg 1 took place in late September and early October, while Leg 2 was carried out during November/December. In order to make data as comparable as possible, each survey operates under a set of agreed standard protocols. Each tow is 30min long and takes place during daylight hours at 3.5-4 knots. Net geometry and ground contact is monitored and logged. All fish and commercial shellfish are sorted to species level prior to taking lengths and other biological measurements such as age, sex and maturity. The primary purpose of the Irish Groundfish Survey is to develop estimates of juvenile abundances for important commercial fish species. Measurements of the abundance of juvenile fish are a critical measure of the health of a stock, serving as an annual indication of recruitment (the number of newly spawned fish which enter the population each year) success or failure. Most importantly, they allow forecasting of future commercial abundance. In addition, the Irish Groundfish Survey provides data on the distribution and biology of commercial and non-commercial species of ecological interest, as well as hydrographic and environmental observations..2007年，爱尔兰海洋研究所（Marine Institute, MI）于‘凯尔特探索号’（RV Celtic Explorer）研究船上开展了本项调查，作为年度底栖鱼类调查的一部分，旨在摸清爱尔兰周边商业鱼类的分布与资源丰度。 爱尔兰底栖鱼类调查（Irish Groundfish Survey, IGFS）是国际底拖网调查（International Bottom Trawl Survey, IBTS）计划的组成部分，该国际调查项目由国际海洋考察理事会（International Council for the Exploration of the Sea, ICES）统筹协调。该调查于每年秋冬两季开展，在爱尔兰海域采集底拖网及配套辅助数据，以生成渔业管理所需的相对资源丰度指数。尤为关键的是，本次调查可获取种群内幼鱼占比的相关指数，进而反映该种群的产卵繁殖成效。爱尔兰底栖鱼类调查还履行了爱尔兰的国际义务，为共同渔业政策（Common Fisheries Policy, CFP）的落地实施提供科学数据支撑。 本次调查通过在预设站位开展系列底栖采样拖网作业完成。2007年的调查分为两个航段：第一航段于9月末至10月初开展，第二航段则在11月至12月期间进行。 为确保数据具备尽可能高的可比性，所有调查均遵循一套统一约定的标准操作规程。每一次拖网作业时长为30分钟，且需在日间以3.5至4节的航速开展。拖网的网具结构与海底接触状态会被实时监测并记录。所有鱼类及经济贝类均需按物种分类，随后测量其体长，并开展年龄、性别与成熟度等生物学指标检测。 爱尔兰底栖鱼类调查的核心目标是对重要商业鱼类的幼鱼资源丰度进行估算。幼鱼资源丰度的测量是评估种群健康状况的关键指标，可作为补充群体（recruitment，即每年新孵化并加入种群的幼鱼总数）繁殖成败的年度衡量依据。尤为重要的是，该数据可用于预测未来的商业性资源丰度。此外，本次调查还会采集具有生态价值的商业与非商业物种的分布及生物学数据，同时获取水文与环境观测资料。