There is a growing call to restore the natural richness of the North Sea, but it is often unclear what this natural richness actually was. Here we review the demise and the historical ecology of an iconic species, the critically endangered Angelshark Squatina squatina in the southern North Sea, using historical books and catch records of 104 individuals brought to the Dutch fish markets. These sources reveal that between 1600 and 1950, Angelsharks were annual visitors to the North Sea, and in some years were fairly commonly observed. The number of recorded individuals peaked in the early twentieth century and between 1945 and 1955, and declined rapidly in the 1960s, with the last recorded observation in 1973. The decline coincides with the introduction of engine-powered fisheries, whereas the full extirpation followed the increased use of diesel-powered beam-trawlers. The recorded observations of Angelsharks were most commonly from the summer season, in accordance with the prevailing notion of Angelsharks migrating to warmer waters in winter. Furthermore, most recorded catches were of newborns and adult females in shallow waters, showcasing the importance of the area for parturition and nursery. Our review exemplifies how a large predator disappeared from a marine food web and shows the importance of historical data to deduce the natural richness of the North Sea.

中文翻译：

---

北海南部标志性的Angelshark Squatina squatina的历史生态和消亡

越来越多的人呼吁恢复北海的自然丰富度，但通常不清楚这种自然丰富度究竟是什么。在这里，我们使用历史书籍和带到荷兰鱼市的 104 只个体的捕捞记录，回顾了北海南部极度濒危的角鲨这种标志性物种的消亡和历史生态。这些资料显示，在 1600 年至 1950 年之间，天使鲨是北海的年度游客，并且在某些年份相当普遍。记录的个体数量在 20 世纪初和 1945 年至 1955 年间达到顶峰，并在 1960 年代迅速下降，最后一次记录观察是在 1973 年。而随着柴油动力拖网渔船的使用增加，完全灭绝。根据天使鲨在冬季迁移到温暖水域的流行观念，对天使鲨的记录观察最常见于夏季。此外，大多数记录的捕获量是浅水区的新生儿和成年女性，这表明该地区对分娩和育儿的重要性。我们的评论举例说明了大型捕食者如何从海洋食物网中消失，并展示了历史数据对于推断北海自然丰富度的重要性。大多数记录的捕获量是浅水区的新生儿和成年雌性，表明该地区对分娩和育儿的重要性。我们的评论举例说明了大型捕食者如何从海洋食物网中消失，并展示了历史数据对于推断北海自然丰富度的重要性。大多数记录的捕获量是浅水区的新生儿和成年雌性，表明该地区对分娩和育儿的重要性。我们的评论举例说明了大型捕食者如何从海洋食物网中消失，并展示了历史数据对于推断北海自然丰富度的重要性。