The Importance of Foraging Pattern on Reproductive Success in the Northern Fur Seal, Callorhinus Ursinus

觅食模式对北方毛皮海豹 (Callorhinus Ursinus) 繁殖成功的重要性

• 批准号: 9500072
• 负责人: Daniel Costa
• 金额: $ 28.52万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9500072&HistoricalAwards=false
• 关键词: Importance; Foraging; Pattern; Reproductive; Success

9500072 Costa Over the last several decades many populations of pinnipeds and seabirds have undergone significant declines. Many hypotheses to explain the declines have been made and numerous studies have been undertaken to search for the underlying causes. Juvenile survival, however, may be one of the most critical factors influencing the growth and recovery of depleted populations of pinnipeds. Maternal resources imparted to offspring prior to weaning are important for a successful transition from nutritional dependence to independence and subsequent survival. This may be particularly so of species whose life histories are constrained by rearing young at high-latitudes and species which wean their young abruptly. Growth and recovery of depleted populations at high-latitudes are further constrained when life- history fecundity schedules limit individuals to producing one offspring per year. Thus, the quantity and quality of maternal investment to the young are a critical determinant of post- weaning survival. This research will examine the relationship between foraging behavior and maternal investment in northern fur seals. The research will be conducted in the Pribilof Islands; Alaska, where lactating northern fur seals have been shown to have three distinct foraging patterns (shallow, deep, and mixed). The location of the Pribilof Islands, near the edge of an extensive continental shelf, fortuitously gives animals breeding there two distinct foraging environments, one on the continental and one off. Each environment has a distinct assemblage of prey species. Previous studies show the deep diving foraging pattern to be associated with foraging over the continental shelf. We will quantify the foraging costs and total investment in pups associated with the different foraging strategies observed in northern fur seals. This will be done by comparing the maternal investment in terms of both the actual energy and material delivered to the pup and the ene rgetic cost to the mother. These data will be used to determine if one foraging strategy is energetically more efficient or beneficial and if this is so, does it allow the mother to make a greater investment in her young.

在过去的几十年里，许多鳍足类动物和海鸟的数量急剧下降。人们提出了许多假设来解释这种下降，并进行了许多研究来寻找潜在的原因。然而，幼鱼的存活可能是影响枯竭鳍足类种群生长和恢复的最关键因素之一。断奶前传递给后代的母体资源对于从营养依赖到独立和随后的生存的成功过渡至关重要。对于那些在高纬度地区养育幼崽受到限制的物种和那些突然断奶的物种来说，这可能尤其如此。当生活史上的繁殖力时间表限制个体每年只能生产一个后代时，高纬度地区枯竭种群的生长和恢复进一步受到限制。因此，母亲对幼崽投资的数量和质量是断奶后存活的关键决定因素。本研究将探讨北方海狗觅食行为与母性投资之间的关系。这项研究将在普里比洛夫群岛进行；在阿拉斯加，哺乳的北方海豹有三种不同的觅食模式（浅海、深海和混合）。普里比洛夫群岛的地理位置靠近广阔的大陆架边缘，这给了在那里繁殖的动物两种截然不同的觅食环境，一种是大陆架，一种是大陆架。每种环境都有不同的猎物种类。先前的研究表明，深潜觅食模式与大陆架上的觅食有关。我们将量化在北方海狗中观察到的不同觅食策略相关的觅食成本和幼崽的总投资。这将通过比较母狗投入的实际能量和物质传递给幼崽和母狗的能量成本来完成。这些数据将用于确定一种觅食策略是否在能量上更有效或更有益，如果是这样，它是否允许母亲在她的孩子身上做出更多的投资。