Hormone comparison between right and left baleen whale earplugs

Area of Science:

• Marine biology
• Endocrinology
• Environmental science

Background:

• Marine animals face increasing environmental and anthropogenic stressors.
• Hormone analysis in biological tissues like earplugs is vital for stress assessment.
• Interchangeability of hormone data from different body tissues is often unverified.

Purpose of the Study:

• To determine if right and left baleen whale earplugs yield interchangeable hormone values.
• To assess methods for standardizing hormone expression across individuals.
• To validate Z-score normalization for analyzing long-term stress trends in whales.

Main Methods:

• Comparison of hormone values (absolute, baseline-corrected, Z-score normalized) from paired right and left earplugs.
• Statistical analysis of hormone differences and confidence intervals.
• Evaluation of Z-score normalization's effectiveness in standardizing hormone variance.

Main Results:

• Absolute hormone values in right and left earplugs showed a positive correlation.
• Z-score normalization was essential for standardizing hormone expression variance.
• Post-normalization, 95% confidence intervals for hormone differences in corresponding earplug laminae included zero, indicating no significant difference.

Conclusions:

• Both right and left baleen whale earplugs are suitable for hormone analysis after Z-score normalization.
• Z-score normalization is critical for accurate interpretation of hormone data and long-term trend analysis.
• This methodology enhances the reliability of using whale earplugs for environmental stress monitoring.