Making the most of monkfish and megrim: survey-based assessments and sustainable exploitation

琵琶鱼（琵琶鱼属），也被称为安康鱼和偏头痛是欧洲最有价值的两种鱼类资源。在这个完全资助的博士生奖学金中，学生将出海调查琵琶鱼和偏头痛，并使用15年的调查数据时间序列，以确定这些神秘鱼类的状况并就其可持续管理提出建议。 该奖学金是MASTS SUPER DTP的一部分，位于阿伯丁大学。该大学位于苏格兰东北部，通过国际机场与欧洲其他地区有着良好的联系，是一个充满活力的海洋生物学研究社区的所在地，其中包括苏格兰海洋科学（MSS），苏格兰政府的主要咨询机构和该项目的合作伙伴。这所大学靠近市中心，就在海岸上，有数英里的桑迪。它还靠近英国最大的国家公园，为对野生动物和海洋环境感兴趣的学生提供梦幻般的生活方式。大多数英国渔民捕获的琵琶鱼在北方大陆架上的丰度没有公认的科学评估，也没有可用于可持续管理的参考点。自2005年以来，海洋科学部每年都对琵琶鱼进行一系列调查（Fernandes等人，2007年）。这些调查的独特之处在于与渔业合作并使用渔业船只进行。它们在提供琵琶鱼绝对丰度估计方面也是独一无二的（Reid等人，2007年），还包括另一个有价值的物种，大眼鲷（Lessorhombus spp.），目前只有相对科学的评估。最近对琵琶鱼进行科学评估的国际基准工作没有得出结论，仍然根据调查生物量估计数管理该种群（“第3类种群”），因此不知道适当的开发率。MSS正在开发基于长度的方法，以提高对琵琶鱼建议的科学基础。 在这项研究中，我们的目标是通过开发一个基于年龄的评估模型来补充这项工作，该模型先前由Fernandes提出（ICES 2013），特别注意模型对任何年龄阅读偏差和错误的敏感性。还将通过分析国际底拖网调查的适当数据，考虑模型对调查范围的敏感性。这些评估方法将通过纳入对年龄、身长和性别的成熟度的审查以及对年龄、身长和性别的自然死亡率的调查加以补充。一旦基于年龄的模型已经完善，学生还将进行管理战略评估（MSE），以确定适当的捕捞和生物量参考点按照国际海洋考察理事会的程序。也有范围应用基于长度的方法对偏头痛。最后，有充分的理由怀疑琵琶鱼，特别是卢西塔尼亚（温水）物种的黑腹鱼（Lophius budegassa），也可能受益于气候变化导致的温度升高。因此，也有范围来检测这些物种的丰度和分布与海水温度变化的关系。 数据将取自MSS（克拉克）提供的琵琶鱼调查的时间序列。Fernandes将通过阿伯丁大学的专门课程和海考会的培训课程提供建模和统计方案编制方面的培训。学生将在学生的头两年参加琵琶鱼调查，这将增加可用的时间序列。学生还将参加ICES凯尔特海洋工作组在哥本哈根ICES总部介绍他们的工作。

Anglerfish (Lophius spp.), also known as monkfish, and megrim are two of the most valuable fish resources in Europe. In this fully funded PhD studentship, the student will take to sea to survey anglerfish and megrim, and use a 15 year time series of survey data, to determine the status and advise on the sustainable management of these enigmatic fish species. The studentship is part of the MASTS SUPER DTP and is based at the University of Aberdeen. Located in the North East of Scotland, with good links to the rest of Europe through an international airport, the university is home to a vibrant marine biology research community, which includes Marine Scotland Science (MSS), the principal advisory agency to the Scottish government and a partner in this project. The university is located close to the city centre, which is right on the coast with miles of sandy beaches. It is also close to the UK's biggest national park, offering a fantastic lifestyle for students interested in wildlife and the marine environment. The anglerfish caught by most UK fishermen have no accepted scientific assessment of their abundance on the northern shelf; nor are there reference points available for use in their sustainable management. A series of surveys, dedicated to anglerfish have been carried out annually by MSS since 2005 (Fernandes et al. 2007). These surveys are unique in being carried out in collaboration with, and using vessels from, the fishing industry. They are also unique in providing an absolute abundance estimate of anglerfish (Reid et al. 2007) and also include another valuable species, the megrim (Lepidorhombus spp.), for which there is only a relative scientific assessment. A recent international benchmark exercise for the scientific assessment of anglerfish was inconclusive and the stock is still managed on the basis of the survey biomass estimates ("category 3 stock") such that appropriate exploitation rates are unknown. MSS are developing length based approaches to improve the scientific basis of the advice on anglerfish. In this studentship the aim is to complement this work by developing an age-based assessment model, previously proposed by Fernandes (ICES 2013), paying particular attention to the sensitivity of the model to any age reading bias and error. Sensitivity of the model to survey coverage will also be considered, by analysing appropriate data from the International Bottom Trawl Survey. These assessment approaches will be complemented by incorporating an examination of maturity at age, length and sex; as well as investigating the natural mortality at age, length and sex. Once the age based model has been refined, the student will also conduct a management strategy evaluation (MSE) to determine appropriate fishing and biomass reference points in accordance with ICES procedures. There is also scope to apply the length based method to megrim. Finally, there is good reason to suspect that anglerfish, particularly the black bellied species (Lophius budegassa) which is a Lusitanian (warm water) species, may also benefit from increasing temperatures due to climate change. So there is also scope to detect changes in the abundance and distribution of these species in relation to changes in sea temperature. Data will be taken from the time series of anglerfish surveys available from MSS (Clarke). Training will be provided in modelling and statistical programming (R) by Fernandes, through dedicated courses at the University of Aberdeen, and at ICES training courses (MSE). The student will participate in the anglerfish surveys in the first two years of the studentship which will augment the time series available. The student will also attend the ICES Celtic Seas Working Group at ICES HQ in Copenhagen to present their work.