Effects of Age and Body Mass on Development of Diving Capabilities of Gray Seal Pups: Costs and Benefits of the Postweaning Fast
Effects of Age and Body Mass on Development of Diving Capabilities of Gray Seal Pups: Costs and Benefits of the Postweaning Fast
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DOI：
10.1086/656925
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发表时间：
2010-11-01
影响因子：
1.6
通讯作者：
Fedak, M. A.
中科院分区：
文献类型：
--
作者：
Bennett, K. A.;McConnell, B. J.;Fedak, M. A.
发展足够的潜水能力对海豹幼崽的生存至关重要，这可能取决于年龄和身体大小。我们利用卫星中继数据记录器跟踪了20只灰海豹幼崽在海上前3个月的潜水行为。我们采用分位数分析来跟踪潜水持续时间和潜水时间百分比的上限，以及水面间隔的下限。当幼犬第一次离开繁殖群体，极端（第95百分位）潜水持续时间和百分比潜水时间呈正相关，与年龄，但质量，出发。极端潜水持续时间和潜水时间百分比在67 +/- 12日龄时达到峰值，其值与成年人相当，但并不持久。更大的峰值在极端的百分比时间花费潜水发生在幼仔，有较高的初始值，年龄在他们的高峰期，并在出发时较重。那些离开殖民地时体型较小、潜水能力较弱的幼崽，一旦在海上，它们的极限潜水时间和潜水时间百分比都有所提高。最短生存时间与离境质量呈正相关。因此，断奶时体重较重的幼崽在离开时既大又老，但较小的幼崽面临权衡。虽然出发时的年龄对早期潜水表现有积极影响，但出发质量对潜水和长期生存的高峰时间百分比有影响。我们推测，一旦小的幼崽已经达到了最低程度的生理发展，以支持潜水，他们将受益于离开殖民地时，年轻，但更大，以最大限度地提高有限的燃料储备，而不是在陆地上经历进一步成熟远离潜在的食物资源，因为穷人潜水员可能能够“赶上”一旦在海上。
Development of adequate diving capabilities is crucial for survival of seal pups and may depend on age and body size. We tracked the diving behavior of 20 gray seal pups during their first 3 mo at sea using satellite relay data loggers. We employed quantile analysis to track upper limits of dive duration and percentage time spent diving, and lower limits of surface intervals. When pups first left the breeding colony, extreme (ninety-fifth percentile) dive duration and percentage time spent diving were positively correlated with age, but not mass, at departure. Extreme dive durations and percentage time spent diving peaked at 67 +/- 12 d of age at values comparable with those of adults, but were not sustained. Greater peaks in extreme percentage time spent diving occurred in pups that had higher initial values, were older at their peak, and were heavier at departure. Pups that were smaller and less capable divers when they left the colony improved extreme dive durations and percentage time spent diving more rapidly, once they were at sea. Minimum survival time correlated positively with departure mass. Pups that were heavier at weaning thus benefitted from being both larger and older at departure, but smaller pups faced a trade-off. While age at departure had a positive effect on early dive performance, departure mass impacted on peak percentage time spent diving and longer-term survival. We speculate that once small pups have attained a minimum degree of physiological development to support diving, they would benefit by leaving the colony when younger but larger to maximize limited fuel reserves, rather than undergoing further maturation on land away from potential food resources, because poor divers may be able to "catch up" once at sea.