Analyzing the Body Condition of Striped Dolphins (Stenella coeruleoalba) Using Histology Methods

Abstract

Dolphins are indicators of marine ecosystem health, and their body condition reflects environmental changes and habitat stability. Striped dolphins (Stenella coeruleoalba) inhabit Hawaiian waters and provide an opportunity to assess the relationship between blubber composition, nutritional status, and general well-being. This study compares blubber histology metrics among four striped dolphins, where one was known to be emaciated at the time of death. Specifically, we assessed whether adipocyte area (AA) and adipocyte index (AI) are indicators of nutritional stress and examined variability among individuals. Blubber samples were taken from multiple body locations according to anatomical landmarks that were based on the girth axis and plane and slides were generated for histological examination. Blubber slides were analyzed according to blubber stratification as outer, middle and inner layers in Fiji (ImageJ) where AA and AI were measured. The collected data was statistically analyzed in R Studio. We expect the layers of the blubber to be stratified in all the dolphins, and we expect to see differences between the emaciated and non-emaciated individuals. These findings will contribute to validating blubber histology as a tool to assess cetacean health and may be used to improve marine ecosystem monitoring efforts.