WINTER ECOLOGY OF STELLER SEA LIONS (Eumetopias jubatus) IN ALASKA
WINTER ECOLOGY OF STELLER SEA LIONS (Eumetopias jubatus) IN ALASKA
复制标题
阿拉斯加北海狮 (Eumetopias jubatus) 的冬季生态
DOI：
10.14288/1.0074830
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Y. Goto
中科院分区：
文献类型：
--
作者：
Y. Goto
这项研究的目的是描述方面的冬季生态的Steller海狮（Eumetopias jubatus）的行为观察在冬季之间的搬运1996年1月至4月在阿拉斯加东南部（木材岛，133° 48' W，55° 41' 45”N）。我的主要假设是：1）母亲照顾雄性后代比照顾雌性后代多，而且在海岸上花更少的时间来满足雄性后代更高的代谢需要。2)母亲与一岁的孩子有更高的要求比那些与小狗，应该花更多的时间护理和更多的时间在海上觅食。另一个重要的目标是描述断奶过程。成熟的女性和他们的依赖年轻人（幼崽年龄< 1岁和1-2岁）占主导地位的冬季拖出来，而成熟的男性和亚成年男性的数量仍然很低。海岸上的动物数量每天都有相当大的变化。一个逐步回归显示，海岸上的数量与天气和海洋条件有关。重要变量的排序依次为：波高、气温、风速、风向、天空覆盖、气压、涌浪、潮高。打捞模式与恶劣的天气和恶劣的海况呈负相关。没有检测到昼夜牵引模式。母亲投资的两个措施：不同性别和年龄段（幼犬和一岁）的哺乳时间，以及他们的母亲在陆地和海上觅食的时间。雄性幼仔哺乳期的平均长度（x = 37.2 ± 2.8 min SE，n=12）之间的差异并不显著长于雌性幼仔的哺乳时间（x = 35.9 ± 2.3 min，n=12）。然而，一岁幼仔的哺乳时间（x = 44.0 ± 2.8 min.SE，n=5）显著长于幼仔（x = 36.5 ± 1.8 min.，n=24）。雄性与母亲在岸上哺乳的时间平均为33.9%（± 1.1 SE），而雌性后代为29.9%（± 4.4），但差异无统计学意义，在3个月的研究期间，比例没有变化。母亲与一岁幼仔的平均出海时间为2.3 d（x = 59.7 ± 4.7 h SE，n=6），显著长于母亲与幼仔的平均出海时间1.9 d（x = 48.0 ± 6.3 h，n=18）。有雄性幼崽（< 1岁）的母亲平均离开2.2天（x = 52.5 ± 15.2小时SE，n=12），而有雌性幼崽的母亲平均离开1.8天（x = 43.5 ± 12.6小时，n=12）。在出发觅食之前，母亲与雄性后代在陆地上的平均时间为35.2 h（± 7.0），与雌性后代在陆地上的平均时间为34.5 h（± 6.0）。成熟的女性（n=30）表现出很小的季节性变化的行程时间。出海之间的海岸访问平均为19.4小时（n=30，SE=0.90，范围11.2- 29.2小时）。后代性别和年龄组之间在海岸上花费的时间差异没有统计学意义。哺乳期雌性动物在海岸上的时间平均为14.2 ± 1.1% SE（n=30），而未成熟动物的时间为3倍（40.2 ± 2.1%）。平均旋转时间（喂养/休息周期）从海上拖出来的成熟女性是3.0天，是一致的整个赛季。1月至4月期间未观察到幼仔和幼仔断奶。在冬季的牵引模式的影响，干扰，海洋和天气条件比内源性的节奏。
The goal of this study was to describe aspects of the winter ecology of Steller sea lions (Eumetopias jubatus) from behavioural observations made at a winter haulout between January and April 1996 in Southeast Alaska (Timbered Island, 133° 48’ W, 55° 41’ 45” N). My major hypotheses were: 1) Mothers suckle male offspring more than female offspring, and spend less time on shore to provide for the higher metabolic needs of males. 2) Mothers with yearlings have higher demands than those with pups and should spend more time nursing and more time at sea foraging. Another important goal was to describe the weaning process. Mature females and their dependent young (pups age < 1 y and yearlings 1-2 y) predominated on the winter haulout while, numbers of mature male and sub-adult males remained low. There was considerable variability in numbers of animals on shore from one day to the next. A Drop-one Stepwise regression showed numbers on shore were correlated with weather and sea conditions. The ranked order of important variables included: wave height, air temperature, wind’ speed, wind direction, sky cover, barometric pressure, ocean swell, and tide height. Haul-out patterns were negatively correlated with poor weather and rough sea conditions. No diurnal haul-out pattern was detected. Two measures of maternal investment were made: the time spent suckling by different sex and age class (pups and yearlings), and the time their mothers spent on land and at sea foraging. Differences between the average length of male pup-suckling bouts (x = 37.2 ± 2.8 min. SE, n=12) were not significantly longer than female suckling time (x = 35.9 ± 2.3 min., n=12). However, yearlings suckled significantly longer (x = 44.0 ± 2.8 min.SE, n=5) than pups (x = 36.5 ± 1.8 min., n=24). Males spent an average of 33.9% (± 1.1 SE) of the time they were with their mothers onshore suckling compared to 29.9% (± 4.4) by female offspring, but the difference was not statistically significant, and the proportions did not change during the 3 month study period. Average trips to sea by mothers with yearlings lasted 2.3 d (x = 59.7 ± 4.7 h SE, n=6) and were significantly longer than the 1.9 d average trips of mothers with pups (x = 48.0 ± 6.3 h, n=18). Mothers with male pups (< 1 y) were away for an average of 2.2 d (x = 52.5 ± 15.2 h SE, n=12) compared to 1.8 d (x = 43.5 ± 12.6 h, n=12) for those with female pups. Mothers spent an average of 35.2 h (± 7.0) on land with male offspring and 34.5 h (± 6.0) with females before departing on foraging trips. Mature females (n=30) showed little seasonal variation in trip duration. Shore visits averaged 19.4 h between trips to sea (n=30, SE=0.90, range 11.2-29.2h). Differences in time spent on shore between offspring genders and age classes were not statistically significant. Lactating females spent an average of 14.2 ± 1.1% SE (n=30) of their time on shore while immature animals spent three times as long (40.2 ± 2.1%). Average rotation time (feeding/resting cycle) from sea to the haulout by mature females was 3.0 days and was consistent through the season. Weaning of pups and juveniles was not observed between January and April. Haul-out patterns during the winter were influenced more by disturbance, sea and weather conditions than by endogenous rhythms.