Castinel A, Duignan P J, Pomroy W E, López-Villalobos N, Gibbs N J, Chilvers B L, Wilkinson I S
New Zealand Wildlife Health Centre, IVABS, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
J Wildl Dis. 2007 Jul;43(3):461-74. doi: 10.7589/0090-3558-43.3.461.
As part of a health survey of New Zealand sea lions (Phocarctos hookeri) on Enderby Island, Auckland Islands (50 degrees 30'S, 166 degrees 17'E), neonatal mortality was closely monitored at the Sandy Bay colony for seven consecutive years. Throughout the breeding seasons 1998-99 to 2004-05, more than 400 postmortem examinations were performed on pups found dead at this site. The primary causes of death were categorized as trauma (35%), bacterial infections (24%), hookworm infection (13%), starvation (13%), and stillbirth (4%). For most pups, more than one diagnosis was recorded. Every year, two distinct peaks of trauma were observed: the first associated with mature bulls fighting within the harem and the second with subadult males abducting pups. In 2001-02 and 2002-03, epidemics caused by Klebsiella pneumoniae increased mortality by three times the mean in nonepidemic years (10.2%). The increased mortality was attributed directly to acute suppurative infection due to the bacterium and also to an increase in traumatic deaths of debilitated pups. Parasitic infection with the hookworm Uncinaria spp. was a common finding in all pups older than three weeks of age and debilitation by the parasite may have contributed to increased susceptibility to other pathogens such as Klebsiella sp. or Salmonella sp. This study provides valuable quantitative data on the natural causes of neonatal mortality in New Zealand sea lions that can be used in demographic models for management of threatened species.
作为对奥克兰群岛恩德比岛（南纬50度30分，东经166度17分）新西兰海狮（胡氏海狗）进行健康调查的一部分，在桑迪湾繁殖地对新生幼崽死亡率进行了连续七年的密切监测。在1998 - 1999年至2004 - 2005年的整个繁殖季节，对在该地点发现死亡的幼崽进行了400多次尸检。死亡的主要原因分类如下：外伤（35%）、细菌感染（24%）、钩虫感染（13%）、饥饿（13%）和死产（4%）。对于大多数幼崽，记录了不止一种诊断结果。每年观察到两个不同的外伤高峰：第一个与成年雄兽在妻妾群中争斗有关，第二个与亚成年雄兽绑架幼崽有关。在2001 - 2002年和2002 - 2003年，肺炎克雷伯菌引起的疫情使死亡率增加到非疫情年份平均死亡率（10.2%）的三倍。死亡率增加直接归因于该细菌引起的急性化脓性感染，也归因于体弱幼崽外伤死亡的增加。钩虫属寄生虫感染在所有三周龄以上的幼崽中很常见，寄生虫导致的体弱可能增加了对其他病原体如克雷伯菌属或沙门氏菌属的易感性。这项研究提供了关于新西兰海狮新生幼崽死亡自然原因的宝贵定量数据，可用于受威胁物种管理的种群统计学模型。
