Corkeron Peter, Rolland Rosalind M, Hunt Kathleen E, Kraus Scott D
National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, USA.
Anderson Cabot Center for Ocean Life, John H. Prescott Marine Laboratory, New England Aquarium, Boston, MA 02110, USA.
Conserv Physiol. 2017 Mar 9;5(1):cox006. doi: 10.1093/conphys/cox006. eCollection 2017.
Immunoassay of hormone metabolites extracted from faecal samples of free-ranging large whales can provide biologically relevant information on reproductive state and stress responses. North Atlantic right whales ( Müller 1776) are an ideal model for testing the conservation value of faecal metabolites. Almost all North Atlantic right whales are individually identified, most of the population is sighted each year, and systematic survey effort extends back to 1986. North Atlantic right whales number <500 individuals and are subject to anthropogenic mortality, morbidity and other stressors, and scientific data to inform conservation planning are recognized as important. Here, we describe the use of classification trees as an alternative method of analysing multiple-hormone data sets, building on univariate models that have previously been used to describe hormone profiles of individual North Atlantic right whales of known reproductive state. Our tree correctly classified the age class, sex and reproductive state of 83% of 112 faecal samples from known individual whales. Pregnant females, lactating females and both mature and immature males were classified reliably using our model. Non-reproductive [i.e. 'resting' (not pregnant and not lactating) and immature] females proved the most unreliable to distinguish. There were three individual males that, given their age, would traditionally be considered immature but that our tree classed as mature males, possibly calling for a re-evaluation of their reproductive status. Our analysis reiterates the importance of considering the reproductive state of whales when assessing the relationship between cortisol concentrations and stress. Overall, these results confirm findings from previous univariate statistical analyses, but with a more robust multivariate approach that may prove useful for the multiple-analyte data sets that are increasingly used by conservation physiologists.
对从自由放养的大型鲸鱼粪便样本中提取的激素代谢物进行免疫分析，可以提供有关生殖状态和应激反应的生物学相关信息。北大西洋露脊鲸（Müller，1776年）是测试粪便代谢物保护价值的理想模型。几乎所有的北大西洋露脊鲸都有个体识别标识，每年能看到大多数个体，系统的调查工作可追溯到1986年。北大西洋露脊鲸数量不足500头，面临人为造成的死亡、发病和其他应激源，而用于为保护规划提供信息的科学数据被认为很重要。在此，我们描述了使用分类树作为分析多激素数据集的替代方法，该方法基于先前用于描述已知生殖状态的北大西洋露脊鲸个体激素谱的单变量模型。我们的树正确分类了来自已知个体鲸鱼的112份粪便样本中83%的年龄组、性别和生殖状态。使用我们的模型能够可靠地分类怀孕雌性、哺乳雌性以及成熟和未成熟雄性。事实证明，非生殖状态（即“静止”状态，未怀孕且未哺乳以及未成熟）的雌性最难区分。有三头雄性，按其年龄传统上会被认为是未成熟的，但我们的树将它们分类为成熟雄性，这可能需要重新评估它们的生殖状态。我们的分析重申了在评估皮质醇浓度与应激之间的关系时考虑鲸鱼生殖状态的重要性。总体而言，这些结果证实了先前单变量统计分析的结果，但采用了更稳健的多变量方法，这可能对保护生理学家越来越多地使用的多分析物数据集有用。
