南极凯尔盖朗海台南象海豹繁殖后运动行为特征分析

Characterization of post-breeding movement behavior of southern elephant seals(Mirounga leonina) in the Kerguelen Plateau, Antarctica

摘要:

南象海豹(Mirounga leonina)为南极海洋生态系统中的重要捕食者,研究该生物行为特征在生态学与生物海洋学方面有着重要意义,但针对凯尔盖朗地区南象海豹的区域性行为特点研究则少有论及。基于凯尔盖朗海台北部安置在南象海豹身上的盐度-温度-深度剖面仪(Conductivity-temperature-depth,CTD)所收集的数据,运用切换状态空间模型(Switching state-space model,SSSM)预测了南象海豹的真实水平运动状况,并分析了其觅食时对水团利用情况以及潜水特征。结果表明:水平方向上,食物资源的不均匀分布驱动南象海豹向生产力更高区域迁徙,它们主要聚集在3个生产力较高的区域进行觅食,其中凯尔盖朗海台东部的觅食区为大部分南象海豹的迁徙目标;垂直方向上,南象海豹的潜水行为不受光照水平影响且个体间运动表现差异显著,但具有频次高、深度大的特征,同时将捕食区间限制在冬季水(Winter water, WW)附近,这可能是在捕食对象分布与种间竞争之间进行权衡的结果。研究结果丰富了对凯尔盖朗群岛南象海豹繁殖后运动行为的认知,以期为今后更好地了解海洋捕食者的运动行为和生态特性,从而进一步阐释南极生态系统功能。

Abstract:

Southern elephant seal (Mirounga leonina) is an important predator in the Antarctic marine ecosystem, and its behavioral characteristics are important in ecological and biological oceanography research, but the regional behavioral characteristics of southern elephant seal in Kerguelen have rarely been studied. In this study, the dataset of CTD attached to southern elephant seals from the northern Kerguelen Plateau were used to predict the horizontal movement of southern elephant seals using a switching-state space model (SSSM), and the water masses preferred for their foraging use and diving characteristics were analyzed. The results showed that, horizontally, the uneven distribution of food resources drove southern elephant seals to migrate to more productive areas, and they mainly gathered in three more productive areas to forage, among which the eastern part of Kerguelen Plateau was the target of most southern elephant seals; vertically, the diving behavior of southern elephant seal was not affected by light level and the movement performance varied significantly among individuals, but had a combination of high frequency and depth, This linited the feeding area to the winter water (WW), which may be the result of a trade-off strategy between the distribution of predation targets and inter specific competition. This study enriches the knowledge of post-breeding behavior of southern elephant seals in Kerguelen Islands, and may provide a better understanding of the behavior and ecological characteristics of marine predators in the future, and thus further illustrate the function of the Antarctic ecosystem.