University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Department, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, Alaska 99801, USA.
University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Department, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, Alaska 99801, USA.
Gen Comp Endocrinol. 2020 Sep 15;296:113540. doi: 10.1016/j.ygcen.2020.113540. Epub 2020 Jun 22.
Developing a better understanding of the stress response is critical to ensuring the health and sustainability of marine mammal populations. However, accurately measuring and interpreting a stress response in free-ranging, large cetaceans is a nascent field. Here, an enzyme immunoassay for corticosterone was validated for use in biopsy samples from male humpback whales (Megaptera novaeangliae). Analyses were conducted on 247 male North Pacific humpback whale blubber samples, including 238 non-calves and 9 calves that were collected on the Hawaiian breeding and Southeast Alaskan feeding grounds from 2004 to 2006. Significant relationships were found when corticosterone concentrations were examined by year, age class and distribution between locations. When examined by year, corticosterone concentrations for male humpback whales were higher in Hawaii in 2004 than in 2005 and 2006 (p < 0.05). Corticosterone concentration also varied by age class with initially high concentrations at birth which subsequently tapered off and remained relatively low until sexual maturity was reached around age 8-10 years. Corticosterone concentrations appeared to peak in male humpback whales around 15-25 years of age. Blubber biopsies from Alaska and Hawaii had similar mean corticosterone concentrations, yet the variability in these samples was much greater for whales located in Hawaii. It is clear that much work remains to be done in order to accurately define or monitor a stress response in male humpback whales and that specific attention is required when looking at age, sex, and yearly trends. Our results suggest that a stress response may be most impacted by age and yearly oceanographic conditions and needs to be initially examined at the individual level.
深入了解应激反应对于确保海洋哺乳动物种群的健康和可持续性至关重要。然而，准确测量和解释自由放养的大型鲸类的应激反应是一个新兴领域。在这里，我们验证了一种用于雄性座头鲸（Megaptera novaeangliae）活检样本的皮质酮酶联免疫吸附测定法。对 2004 年至 2006 年在夏威夷繁殖地和东南阿拉斯加觅食地采集的 247 只雄性北太平洋座头鲸的 238 只非幼鲸和 9 只幼鲸的鲸脂样本进行了分析。当按年份、年龄组和地点分布检查皮质酮浓度时，发现了显著的相关性。当按年份检查时，2004 年夏威夷雄性座头鲸的皮质酮浓度高于 2005 年和 2006 年（p<0.05）。皮质酮浓度也因年龄组而异，出生时最初浓度较高，随后逐渐下降，直到 8-10 岁左右达到性成熟时才保持相对较低。皮质酮浓度似乎在雄性座头鲸 15-25 岁左右达到峰值。来自阿拉斯加和夏威夷的鲸脂活检样本的皮质酮浓度平均值相似，但在夏威夷的鲸鱼样本中，其变异性要大得多。显然，为了准确定义或监测雄性座头鲸的应激反应，还有很多工作要做，而且在研究年龄、性别和年度趋势时需要特别注意。我们的研究结果表明，应激反应可能受年龄和年度海洋条件的影响最大，需要首先在个体水平上进行检查。
