What is the role of discarding in the dynamics of the demersal fish community of the Firth of Clyde?

丢弃物在克莱德湾底层鱼类群落动态中发挥什么作用？

• 批准号: 2269325
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2269325
• 关键词: What; role; discarding; dynamics; demersal

The Firth of Clyde has notoriously been referred to as an 'ecological desert' having been intensively overfished (Thurstan and Roberts, 2010). Circumstantially, it appears that intensive fishing may have driven the community to undergo the change (Heath and Speirs, 2012). However, given that targeted fishing for white-fish has all but ceased in the area, why has the community not recovered over an almost 20 year period? One hypothesis for the lack of recovery of the Clyde demersal fish community is that by-catch of demersal fish in the trawl fishery for prawns is sufficient to maintain a high, but hidden, mortality rate on the stocks despite best efforts to reduce by-catch by the industry.The purpose of this project is to conduct a comprehensive extraction and synthesis of all the relevant data for demersal fish species in the Firth of Clyde. Then, combined with data from the archive of scientific trawl surveys, develop stock assessment models for the main fish species that will enable us to determine the role fishing in the dynamics of the fish community, and better define what remediation strategies are necessary to restore a healthy stock status in the Clyde.Marine Scotland Science has maintained an observer programme in the Firth of Clyde since at least 1982, sampling landings and discards of demersal fish from both demersal otter trawlers and prawn trawlers. The student would need to spend some time at MSS in Aberdeen to compile data from the observer and market sampling databases. Thereafter, the time would be spent at Strathclyde, with regular trips to Aberdeen, working on the data and developing the stock assessments.The stock assessment methodology will build on recent publications describing new methods for data-sparse stocks, and length-based methods (Cook and Heath, 2018). These methodologies are set in a Bayesian parameter estimation framework so as to provide robust credible intervals around the results.The data handling and statistical modelling skills learned during the project will prepare the student for a wide range of careers in business, industry and government, as well as in science.

克莱德湾因过度捕捞而被称为“生态沙漠”（Thurstan和Roberts，2010年）。在特定情况下，密集捕捞似乎可能促使该群落发生变化（Heath和Speirs，2012年）。然而，鉴于该地区有针对性的白鱼捕捞几乎已经停止，为什么该社区在近20年的时间里没有恢复？关于克莱德底层鱼类群落没有恢复的一个假设是，拖网捕捞对虾的底层鱼类副渔获物足以维持鱼类种群的高但隐藏的死亡率，尽管渔业界尽最大努力减少副渔获物，本项目的目的是全面提取和综合克莱德湾底层鱼类物种的所有相关数据。然后，结合科学拖网调查档案中的数据，为主要鱼种建立种群评估模型，使我们能够确定捕捞在鱼类群落动态中的作用，并更好地确定恢复克莱德湾健康种群所需的补救战略。苏格兰海洋科学至少自1982年以来一直在克莱德湾维持观察员方案，对底栖水獭拖网渔船和虾拖网渔船的底栖鱼上岸和丢弃物进行采样。学生需要花一些时间在阿伯丁的MSS，从观察者和市场抽样数据库中编译数据。此后，时间将花在斯特拉斯克莱德，定期前往阿伯丁，工作的数据和开发股票评估.股票评估方法将建立在最近的出版物描述新的方法数据稀疏股票，和基于长度的方法（库克和希思，2018）.这些方法都设置在贝叶斯参数估计框架，以提供可靠的可信区间周围的结果。在项目期间学到的数据处理和统计建模技能将为学生在商业，工业和政府以及科学领域的广泛职业生涯做好准备。