Environmental determinants of fecundity and pup growth in fur seals

This indicator is no longer maintained, and is considered OBSOLETE.INDICATOR DEFINITIONThe fecundity (pupping rates) of female fur seals and the growth rates of their pups relative to changes in sea surface temperatures (local primary production) in the vicinity of Macquarie Island.TYPE OF INDICATORThere are three types of indicators used in this report:1.Describes the CONDITION of important elements of a system;2.Show the extent of the major PRESSURES exerted on a system;3.Determine RESPONSES to either condition or changes in the condition of a system.This indicator is one of: CONDITIONRATIONALE FOR INDICATOR SELECTIONA highly negative correlation has been detected between sea surface temperatures in the vicinity of Macquarie Island and fur seal fecundity and pup growth. A dataset of over ten years has shown that autumn sea-surface temperatures are highly negatively correlated with female fecundity in the following breeding season.Rather than the reproductive success in terms of fecundity and pup growth being seen simply as a correlate of SST and presumably ocean productivity, the measure is much more than this. What the dataset from the Macquarie Island fur seal populations is rather more unique, in that they indicate how environmental variability effects the reproductive success of animals at annual and lifetime scales. This is especially important as we can now show what impacts environmental/climatic phenomena such as the Antarctic Circumpolar Wave, and global warming will have on fur seals, and how changes in the environment may impact on the viability of populations. In this situation, the data clearly suggest that warmer ocean temperatures significantly effect the reproductive success of fur seals. Sustained warmer temperatures would therefore impose demographic constraints on populations.DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAMSpatial scale: SST data are obtained from a 1 degree square just north of the island that represents the region in which most females obtain food throughout their lactation period.Frequency: Data on the reproductive success of fur seals is to be collected annually.Measurement technique: Each breeding season (November-January), the reproductive success of tagged females is monitored, including their pupping success, and the growth rates of their pups.RESEARCH ISSUESLINKS TO OTHER INDICATORS

本指标已停止维护，被列为废弃指标。
【指标定义】本指标聚焦麦夸里岛（Macquarie Island）周边海域的海面温度（Sea Surface Temperature, SST，当地初级生产力）变化，对应雌性海狗（fur seal）的繁殖力（产仔率）及其幼崽的生长速率。
【指标类型】本报告共采用三类指标：1. 描述系统关键组成要素的状态；2. 体现对系统施加的主要压力程度；3. 评估系统状态或状态变化所引发的响应。本指标属于第一类：状态指标。
【指标遴选依据】研究已在麦夸里岛（Macquarie Island）周边海域的海面温度与海狗繁殖力、幼崽生长速率之间检测到显著负相关关系。一项跨度超十年的数据集显示，秋季海面温度与次年繁殖季的雌性海狗繁殖力呈高度负相关。海狗以繁殖力和幼崽生长速率衡量的繁殖成功率，并非仅与SST及推测的海洋生产力相关，该指标的意义远不止于此。麦夸里岛（Macquarie Island）海狗种群的数据集具有独特价值：它揭示了环境变异如何在年度及终生尺度上影响动物的繁殖成功率。这一点尤为关键，因为我们可借此明确南极环极波（Antarctic Circumpolar Wave）等环境/气候现象以及全球变暖对海狗种群的影响，以及环境变化如何作用于种群存续能力。本数据清晰表明，海洋温度升高会显著影响海狗的繁殖成功率，因此持续的高温将对种群施加种群统计学层面的限制。
【指标监测方案设计与实施策略】空间尺度：海面温度数据取自该岛以北1°见方的海域，该区域覆盖了绝大多数雌性海狗在泌乳期的觅食范围。监测频率：海狗繁殖成功率数据需每年采集一次。测量方法：在每个繁殖季（11月至次年1月），对佩戴标识的雌性海狗的繁殖成功率进行监测，涵盖其产仔成功率及幼崽生长速率。
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