Difference among colonies in the population structure of otariids can be driven by philopatry and/or by specializations in the foraging ecology of females. In northern Patagonia, the South American sea lion (SASL) shows some degree of spatial genetic structure among colonies from north and south zones. This study aims to explore the isotopic niche of SASL females in the last period of the pregnancy from different colonies of northern Patagonia and to consider whether the fine scale genetic spatial structuring is potentially related to variation in trophic resources. Stable isotope analysis was performed on 101 skin samples of newborn pups in 10 colonies, as a proxy for the feeding ecology of their mothers. Differences among colonies in the metrics studied revealed the plasticity of the species and support individual trophic specialization of SASL females at a small geographic scale. Also, significant differences were found in all isotopic metrics between the north and south zones. Several hypotheses were proposed to explain the differences in SASL females' isotope values (e.g., use of different foraging areas or prey, isotopic baseline variation). Nonetheless, further research is needed to better understand the relation between fine scale genetic structuring and the foraging ecology of SASL females.

中文翻译：

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南美小海狮的营养资源在较小地理范围内的变化

耳opa虫和/或雌性觅食生态学的专长可能会导致otar​​iids种群结构中不同菌落之间的差异。在巴塔哥尼亚北部，南美海狮（SASL）在来自北部和南部地区的殖民地中显示出一定程度的空间遗传结构。这项研究的目的是探索巴塔哥尼亚北部不同殖民地SASL雌性在怀孕最后一个时期的同位素位，并考虑精细尺度的遗传空间结构是否可能与营养资源的变化有关。在10个菌落中对101只新生幼仔的皮肤样本进行了稳定的同位素分析，以此作为其母亲的喂养生态的代名词。研究指标之间的殖民地差异揭示了该物种的可塑性，并在较小的地理范围内支持了SASL雌性个体的营养特化。同样，在北部和南部区域之间的所有同位素指标中都发现了显着差异。提出了几种假设来解释SASL雌性同位素值的差异（例如，使用不同的觅食区或猎物，同位素基线变化）。尽管如此，仍需要进一步的研究以更好地理解小规模遗传结构与SASL雌性觅食生态之间的关系。使用不同的觅食区或猎物，同位素基线变化）。尽管如此，仍需要进一步的研究以更好地理解小规模遗传结构与SASL雌性觅食生态之间的关系。使用不同的觅食区或猎物，同位素基线变化）。尽管如此，仍需要进一步的研究以更好地理解小规模遗传结构与SASL雌性觅食生态之间的关系。