To improve spatiotemporal data collection and inform future spurdog Squalus acanthias stock assessment, a new dedicated longline survey was initiated in 2021 in coastal waters of southern Norway. The survey comprised a mixture of randomly predefined stations to facilitate unbiased abundance estimates and supplementary stations including informant putative hotspots. During 25 survey days in autumn 2021, 287 stations were sampled, of which 280 were categorized as “satisfactory” in terms of gear quality deployment. Spurdog catches (n = 954) were more abundant in southeast coastal shallower waters (19–150 m). No length, sex, or maturity stratified schooling behavior was found with increasing catches. Females were more abundant and larger than males, but males were older. Growth and reproduction parameters were within ranges reported for the stock. Our results provide valuable input for spurdog survey designs with regards to optimizing boat time, location of stations, and biological sampling protocols. The survey provides important data for monitoring the spurdog stock and other data-limited species, especially considering the newly re-opened spurdog fishery but also to study possible future effects of climatic changes on spurdog distribution.

中文翻译：

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挪威海岸马刺犬分布和生活史的延绳调查

为了改进时空数据收集并为未来的刺角鲨种群评估提供信息，2021 年在挪威南部沿海水域启动了一项新的专门延绳钓调查。该调查包括随机预定义的站点的混合，以促进公正的丰度估计和补充站点，包括线人假定的热点。在 2021 年秋季的 25 个调查日中，对 287 个站点进行了抽样，其中 280 个站点在装备质量部署方面被归类为“满意”。东南沿海浅水区（19-150 m）的马刺鱼渔获量（n  = 954）更为丰富。随着捕获量的增加，没有发现长度、性别或成熟度分层的学校教育行为。雌性比雄性数量更多、体型更大，但雄性年龄更大。生长和繁殖参数均在该种群报告的范围内。我们的结果为马刺犬调查设计在优化航行时间、站点位置和生物采样方案方面提供了宝贵的输入。该调查为监测马刺犬种群和其他数据有限的物种提供了重要数据，特别是考虑到新近重新开放的马刺犬渔业，同时也研究了气候变化对马刺犬分布未来可能产生的影响。