Aerobic Microorganisms Identified Over a Fourteen-Month Period from the Upper Respiratory Tract of Captive Hawaiian Monk Seals (Monachus schauinslandi)

Infectious disease is a growing concern for the overall declining Hawaiian monk seal (HMS) (Monachus schauinslandi) population. Recently, the HMS population in the main Hawaiian Islands (MHI) is increasing, and this may result in additional rehabilitation and release events. A key aspect for population health assessment is to identify the "normal" bacteria flora (e. g., the upper respiratory tract). Our current knowledge for the HMS flora is based on microbial isolates from stranding or mortality events rather than on healthy animals. This 14-mo study includes 52 oral and 55 nasal sampling events from the two healthy resident HMSs at the Waikiki Aquarium in Honolulu, Hawaii. Extensive culturing, Gram stains, phenotypic (e. g., biochemical), and genotypic (16S rRNA sequencing) characterization were used to identify aerobic microorganisms from the upper respiratory tract. The study detected 30 species of Gram negative bacteria, 18 species of Gram positive bacteria, and two species of yeast. The "normality" of the bacterial population was established over the study time period by consistent recovery of identical bacterial species from upper respiratory tract samplings. These results may provide a baseline for normal aerobic bacterial flora in these seals. These results may also allow for comparison to other HMSs in facilities and their wild conspecifics, and have implications for diagnosis of infection in diseased animals.