Foraging behaviour of Weddell seals, and its ecological implications
Foraging behaviour of Weddell seals, and its ecological implications
复制标题
威德尔海豹的觅食行为及其生态意义
作者：
J. Plötz;H. Bornemann;R. Knust;A. Schröder;M. Bester
摘要。1998年2月，在威德尔海东部海岸的德雷舍尔湾，8只成年威德尔海豹（Leptonychotes weddellii）的时间 - 深度记录仪数据提供了为期8天的同步潜水记录。海豹主要在两个深度层内觅食，一个是从海面到160米，此处温度和盐度变化很大；另一个是靠近海底的340米到450米，这里温度最低且盐度最高。虽然在白天浮游和底栖潜水都会发生，但海豹在夜间几乎只在上层水体中觅食。白天的拖网作业证实，南极新拟冰鱼（Pleuragramma antarcticum）在远洋和靠近海底的区域都是数量最多的鱼类。在110 - 170米深度的夜间浮游拖网显示南极新拟冰鱼的生物量变化很大。南极新拟冰鱼在当地数量的时间变化，特别是在远洋区域的变化，可能解释了海豹浮游和底栖觅食活动的趋势。本研究描述了一只捕猎海豹的下颌运动，这可能是进食行为的指示。文中还讨论了从威德尔海豹到鱼类、浮游动物以及磷虾（Euphausia superba）的营养联系。
Abstract. Time-depth recorder data of eight adult Weddell seals (Leptonychotes weddellii) provided simultaneous dive records over 8 days in the Drescher Inlet, eastern Weddell Sea coast, in February 1998. The seals primarily foraged within two depth layers, these being from the sea surface to 160 m where temperature and salinity varied considerably, and near the bottom from 340 to 450 m where temperature was lowest and salinity highest. While both pelagic and benthic diving occurred during daylight, the seals foraged almost exclusively in the upper water column at night. Trawling during daytime confirmed that Pleuragramma antarcticum were by far the most abundant fish both in the pelagial and close to the bottom. Pelagic night hauls at 110–170 m depth showed highly variable biomass of P. antarcticum. The temporal changes in the local abundance of P. antarcticum, particularly in the pelagial, may explain the trends in the seals' pelagic and benthic foraging activities. This study describes the jaw movements of a hunting seal, which are presumably indicative of feeding events. Trophic links from the Weddell seal to fish, zooplankton and krill, Euphausia superba, are discussed.