Fish nurseries in a changing world: towards functional indicators of habitat quality

确定和保护“基本鱼类生境”正在成为研究、管理和政策的优先事项。保护每个生命阶段所需的栖息地是创造可持续渔业和保护受威胁物种所必需的，但对鱼类栖息地需求的了解非常有限，特别是对幼鱼而言。青少年往往严重依赖于受人类活动严重影响的浅水近岸地区。人们对这些幼鱼阶段知之甚少，因为它们很少被商业渔业或独立调查所针对。目前，幼鱼栖息地的质量通常是简单地根据其所含鱼类的丰度来评估的。鱼类生长、存活和进入成鱼群体等功能指标往往被忽视，但这些指标对于量化不同地区作为鱼类苗圃的重要性至关重要。方法这个博士项目包括1）实验室实验，以开发新的分子和地球化学指标的喂养，生长和运动的自由放养的幼鱼;和2）在塞文河口广泛的实地工作，在现实生活中应用这些工具，并确定关键的栖息地需要的商业价值的物种，共同唯一的比目鱼。培训学生将接受一系列技能的培训，建立在分子生长指数，饮食特征的DNA元编码和营养和连接重建的生物地球化学示踪剂的主管的核心专业知识：不仅与渔业相关的关键技术，而且广泛地跨越环境研究学科。“海洋生态学”咨询公司（CASE合作伙伴）和德文郡和塞文近海渔业和保护局（合作伙伴）提供了一个独特的平台，用于对具有挑战性的河口环境进行采样，并在应用创新研究以支持海洋政策和管理决策方面积累经验。

Scientific Background The identification and conservation of "Essential Fish Habitat" is emerging as a research, management and policy priority. Protecting habitats required for every life-stage is necessary to create sustainable fisheries and conserve threatened species, but knowledge of fish habitat needs is very limited, particularly for juveniles. Juveniles are often critically dependent on shallow, inshore areas which are heavily impacted by human activities. Little is known about these young stages because they are rarely targeted by commercial fisheries or fisheries-independent surveys. Currently, juvenile habitat quality is typically assessed simply on the basis of the abundance of fish they contain. Functional indicators such as fish growth, survival and movement into the adult population are often overlooked, but are essential to quantifying the importance of different areas as fish nurseries. Methodology This PhD project involves 1) laboratory experiments to develop novel molecular and geochemical indices of feeding, growth and movement in free-ranging juvenile fish; and 2) extensive field work in the Severn Estuary to apply these tools in a real-life setting and identify key habitat needs of a commercially valuable species, the common sole Solea solea. Training The student will be trained in a range of skills, building on core expertise of the supervisors in molecular growth indices, DNA metabarcoding for diet characterisation, and biogeochemical tracers for trophic and connectivity reconstruction: key techniques relevant not just for fisheries, but broadly across environmental research disciplines. The consultancy 'Ocean Ecology' (CASE partner) and the Devon and Severn Inshore Fisheries and Conservation Authority (collaborative partner) offer a unique platform for sampling challenging estuarine environments and experience in applying innovative research to support marine policy and management decisions.