Atlantic herring (Clupea harengus) plays a key role within temperate marine food webs and is targeted by a significant over-regional fishery. Due to its high economic importance, dynamics in herring stock biomass and recruitment are closely monitored, forming the basis for fisheries management advice. As recruitment patterns translate into the adult stock biomass, early life stage ecology has been thoroughly addressed in fisheries research. Larval monitoring programs commonly focus on length measurements and abundance indices, rarely, information on larval developmental stages is given. As length is highly influenced by temperature, salinity and food availability, their size range can significantly vary between cohorts, populations, and ecotypes. Nowadays, a systematic staging system from the 1970s provides the standard guide for herring larval development, although it does not fully resolve important developmental stages. Here, we propose an improved staging system based on external morphology and skeletal development of herring larvae. The staging system has been developed and tested with herring larvae from different populations of the North and Baltic Sea to ensure applicability. The system comprises 15 stages (+substages) in 5 major developmental phases: the yolk sac phase, the dorsal fin development, the caudal fin development, the pelvic fin development, and the juvenile phase. This staging system aims to simplify herring larval staging to gain a more specific picture of early life dynamics. Because of the detailed description of the development, future studies are better equipped to identify stages which, for example, show high mortality rates and better link them to environmental circumstances.

中文翻译：

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基于外部形态和骨骼发育的大西洋鲱鱼（Clupea harengus）幼虫的分期系统

大西洋鲱鱼 ( Clupea harengus）在温带海洋食物网中发挥着关键作用，并且是重要的跨区域渔业的目标。由于其高度的经济重要性，鲱鱼种群生物量和补充的动态受到密切监测，形成渔业管理建议的基础。随着补充模式转化为成鱼生物量，早期生命阶段的生态学已在渔业研究中得到彻底解决。幼虫监测计划通常侧重于长度测量和丰度指数，很少提供幼虫发育阶段的信息。由于长度很大程度上受温度、盐度和食物供应的影响，它们的大小范围在群体、种群和生态类型之间可能存在显着差异。如今，20 世纪 70 年代的系统分期系统为鲱鱼幼虫的发育提供了标准指南，尽管它没有完全解决重要的发展阶段。在这里，我们提出了一种基于鲱鱼幼虫外部形态和骨骼发育的改进分期系统。该分期系统已经开发出来，并用来自北海和波罗的海不同种群的鲱鱼幼虫进行了测试，以确保适用性。该系统包括 5 个主要发育阶段的 15 个阶段（+子阶段）：卵黄囊阶段、背鳍发育、尾鳍发育、腹鳍发育和幼鱼阶段。该分期系统旨在简化鲱鱼幼虫分期，以获得早期生命动态的更具体图片。由于对发展的详细描述，未来的研究可以更好地确定阶段，例如：