Beached bachelors: An extensive study on the largest recorded sperm whale Physeter macrocephalus mortality event in the North Sea

Between the 8th January and the 25th February 2016, the largest sperm whale Physeter macrocephalus mortality event ever recorded in the North Sea occurred with 30 sperm whales stranding in five countries within six weeks. All sperm whales were immature males. Groups were stratified by size, with the smaller animals stranding in the Netherlands, and the largest in England. The majority (n = 27) of the stranded animals were necropsied and/or sampled, allowing for an international and comprehensive investigation into this mortality event. The animals were in fair to good nutritional condition and, aside from the pathologies caused by stranding, did not exhibit significant evidence of disease or trauma. Infectious agents were found, including various parasite species, several bacterial and fungal pathogens and a novel alphaherpesvirus. In nine of the sperm whales a variety of marine litter was found. However, none of these findings were considered to have been the primary cause of the stranding event. Potential anthropogenic and environmental factors that may have caused the sperm whales to enter the North Sea were assessed. Once sperm whales enter the North Sea and head south, the water becomes progressively shallower (

2016年1月8日至2月25日期间，北海发生有记录以来规模最大的抹香鲸（Physeter macrocephalus）死亡事件：六周内共有30头抹香鲸在5个国家搁浅。所有搁浅个体均为未成年雄性。种群按体型分层分布，体型较小的个体在荷兰搁浅，体型最大的个体则在英格兰搁浅。其中绝大多数（n=27）搁浅个体接受了尸检和/或采样，为本次死亡事件的跨国全面调查提供了可行基础。这些抹香鲸的营养状况尚可至良好，除搁浅引发的病理损伤外，未发现明显的疾病或创伤迹象。本次调查检出多种病原体，包括各类寄生虫、数种细菌与真菌致病菌，以及一种新型α疱疹病毒（alphaherpesvirus）。对其中9头抹香鲸的检测中发现了多种海洋垃圾。但上述所有发现均未被认定为本次搁浅事件的主要诱因。研究人员对可能导致抹香鲸进入北海的人为与环境潜在因素进行了评估。一旦抹香鲸进入北海并向南行进，海水会逐渐变浅（