2019 - 2020 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Inshore longline fisheries in the Southern North Sea 2019/20 - Fisheries Science Partnership

This work was carried out as part of the Fisheries Science Partnership (FSP) programme. The overall aims of this project were to examine i) the seasonal catch rates of fish taken in the southern North Sea demersal longline fishery; ii) catch composition of all discarded and retained fish; iii) vitality of commercially important skate and ray species, focusing on thornback ray *Raja* *clavata* ; iv) post-release behaviour and discard survival of discarded thornback ray through an electronic tagging programme. On each occasion longlines were deployed, the positional information, soak times, and number of hooks/baths were recorded, and for all species of fish length distribution data were taken. For electronically tagged fish the release date, release position and individual length, wing width, sex and maturity were recorded.本研究作为渔业科学合作计划（Fisheries Science Partnership，FSP）的组成部分开展。本项目的总体目标为：① 探究北海南部底栖延绳钓渔业所捕捞鱼类的季节性捕捞率；② 分析所有丢弃及留存鱼类的渔获组成；③ 研究具有商业价值的鳐与魟类物种的存活活力，重点以棘鳐（*Raja clavata*）为研究对象；④ 通过电子标记计划，探究被丢弃棘鳐的放归后行为与丢弃个体存活率。 每次部署延绳钓时，均记录作业位置信息、钓绳浸泡时长以及钓钩/钓组数量，并采集所有鱼类物种的体长分布数据。 对于搭载电子标记的鱼类，记录其放归日期、放归位置、个体体长、体盘宽度、性别及成熟度。