Trophic Interactions and Population Trends of Killer Whales (Orcinus orca) in the Southern Ross Sea
Trophic Interactions and Population Trends of Killer Whales (Orcinus orca) in the Southern Ross Sea
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DOI：
10.1578/am.38.2.2012.153
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发表时间：
2012-01-01
期刊：
影响因子：
1.2
通讯作者：
Ballard, Grant
中科院分区：
文献类型：
--
作者：
Ainley, David G.;Ballard, Grant
报道了2002 - 2010年南极罗斯海罗斯岛附近B型和C型虎鲸的觅食事件及其数量变化趋势。更新早期的报告，罗斯海虎鲸（C型; RSKWs）的目击频率和每次目击的个体数量，一种以捕鱼为生的生态类型，继续减少，与重要猎物的数量和大小减少相一致：南极齿鱼（Dissostichus mawsoni）。越来越罕见的大型鱼类能量密度更高，对鲸鱼也可能具有重要的社会意义，这种关系可能与东北太平洋的食鱼虎鲸和大型奇努克鲑鱼（Oncorhynchus tshawytscha）之间的关系相似。相比之下，在罗斯海南部研究区，体型较大、以哺乳动物为食的B型虎鲸的流行率没有变化。捕食事件B型虎鲸涉及威德尔海豹（Leptonychotes weddellii），在大型企鹅的兴趣，如皇帝（Aptenodytes forsteri），和缺乏兴趣的小企鹅，如阿德利斯（Pygoscelis adeliae），提出。在这两种虎鲸形式的情况下，罗斯海接壤的大海湾的快速冰的季节性分解可能提供可靠的，增强的觅食机会，因为猎物在夏季一次暴露在一个区域。鉴于RSKW的流行和大型洋枪鱼的可用性之间的明显关系，我们推测，目前的管理策略，南极洋枪鱼在罗斯海地区威胁到目前的人口水平RSKW。
Foraging events and related trends in numbers of Type-B and -C killer whales (Orcinus orca) are reported for the vicinity of Ross Island, Ross Sea, Antarctica between 2002 and 2010. Updating an earlier report, the frequency of sightings and the number of individuals per sighting of Ross Sea killer whales (Type-C; RSKWs), a fishing-eating ecotype, has continued to decrease in a pattern coincident with a decrease in the number and size of an important prey: Antarctic toothfish (Dissostichus mawsoni). Increasingly rare, large fish are much more energetically dense and may also be socially important to the whales, a relationship with potential parallels to that known between well-studied fish-eating killer whales and large Chinook salmon (Oncorhynchus tshawytscha) in the northeast Pacific. In contrast, the prevalence of the larger, mammal-eating Type-B killer whales has not changed in the southern Ross Sea study area. Predation events by Type-B killer whales involving Weddell seals (Leptonychotes weddellii), interest in large penguins, such as emperors (Aptenodytes forsteri), and lack of interest in small penguins, such as Adelies (Pygoscelis adeliae), are presented. In the case of both killer whale forms, the progressive seasonal breakup of fast ice in large bays bordering the Ross Sea likely provides reliable, enhanced foraging opportunities as prey are exposed one area at a time during summer. Given the apparent relationship between RSKW prevalence and the availability of large toothfish, we speculate that the current management strategy of Antarctic toothfish in the Ross Sea region threatens current population levels of RSKWs.