Assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. Hair is increasingly being used to investigate stress-related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. We validated enzyme immunoassays for measuring aldosterone, cortisol, corticosterone, and testosterone in lanugo (natal hair grown in utero) samples collected from Steller sea lions (Eumetopias jubatus), California sea lions (Zalophus californianus), and northern fur seals (Callorhinus ursinus). We applied laboratory validation methods including recovery of added mass, parallelism and dilution linearity. We found no effects due to differences in alcohol- versus detergent-based cleaning methods. Further, there were no significant differences in hormone concentrations in hair samples collected immediately after the molt and the subsequent samples collected over 1 year, indicating steroid hormones are stable once deposited into pinniped hair. We found no sex differences in any hormone concentrations, likely due to the lanugo being grown in utero and influenced by maternal hormone concentrations. For Steller sea lion and California sea lion pups, we found hormone concentrations significantly differed between rookeries, which warrants future research. Hair provides a novel tissue to explore the intrinsic or extrinsic drivers behind hormone measurements in otariids, which can be paired with multiple health-related metrics to further investigate possible drivers of physiological stress.

中文翻译：

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来自北太平洋三种ari类物种的头发中与压力有关的生殖激素：斯特勒海狮，加利福尼亚海狮和北部海狗。

评估应激因素对夹足动物的生理影响在逻辑上具有挑战性，并且许多激素会因捕获和处理而改变，从而限制了代谢活跃组织的效用。由于采用了侵入性较小的采集方法，人们越来越多地将头发用于研究与野生生物种群相关的压力相关和生殖激素，一旦生长，头发就具有代谢惰性，并且含有多种具有生态价值的生物标记。我们验证了酶免疫法的测定方法，可用于测量从Steller海狮（Eumetopias jubatus），加州海狮（Zalophus californianus）和北部海狗（Callorhinus ursinus）收集的胎毛（子宫内生长的新生毛）样本中的醛固酮，皮质醇，皮质酮和睾丸激素。我们应用了实验室验证方法，包括增加质量的回收率，平行度和稀释线性。由于基于酒精的清洁剂与基于洗涤剂的清洁方法不同，我们没有发现任何影响。此外，在蜕皮后立即收集的头发样本中和随后超过1年的后续样本中，激素浓度没有显着差异，表明类固醇激素一旦沉积到针扎式头发中便是稳定的。我们发现任何激素浓度均无性别差异，可能是胎毛在子宫内生长并受母体激素浓度影响。对于斯特勒海狮和加利福尼亚海狮幼崽，我们发现各家禽舍之间的激素浓度显着不同，这值得进一步研究。毛发提供了一种新颖的组织，可探索耳ari类激素测量背后的内在或外在驱动因素，