This collaborative project explored the gut bacterial communities of Guadalupe fur seals (Arctocephalus philippii townsendii) in the context of an emerging alopecia syndrome first noted a decade ago alongside anomalous warm‐water events and shifts in otariid foraging behaviour. Although marine‐mammal microbiome research has primarily focused on bacteria, its role in wildlife pathologies such as hair loss remains uncharted. 

The study was conducted in partnership with Dr. Karina Acevedo Whitehouse and M.Sc. Paulina Nieves, and aimed to determine whether seals exhibiting alopecia differ in gut‐microbiome composition and functional potential compared to healthy controls, thereby implicating diet‐ or metabolism‐driven mechanisms in disease risk.

High‐throughput 16S rRNA sequencing revealed that diversity was similar across groups. Yet, affected animals showed shifts in community structure—five phyla were enriched and two depleted, with Parabacteroides, Bacteroides, Lachnospiraceae, Erysipelotrichaceae, and Roseburia notably overrepresented in alopecic seals. Of 6,380 predicted functional pathways, 163 differed between alopecic and non-alopecic animals. These findings provide preliminary evidence that diet‐linked alterations in gut microbiota and their metabolic functions may contribute to alopecia in Guadalupe fur seals, warranting targeted follow-up to pinpoint the causal microbial mechanisms.

📄 (Submitted to Veterinary microbiology in August 2025)

This project characterized the nasal and anal microbiota of two sympatric seal species in the subarctic—the harbour seal (Phoca vitulina, n=11) and the ringed seal (Pusa hispida, n=6)—using 16S rRNA amplicon sequencing. While most marine-mammal microbiome work has focused on gut communities, little is known about microbiota at other anatomical sites and their ecological roles.

This study was conducted during my postdoctoral fellowship at Fisheries and Oceans Canada (DFO), in collaboration with researchers from the University of Manitoba and the Assiniboine Park Zoo (Manitoba). It aimed to evaluate whether microbial composition and diversity differ between nasal and anal sites and between host species.

We observed that anal samples were generally dominated by Firmicutes, whereas nasal samples were Proteobacteria-rich, with each species showing distinct dominant genera. Ringed seals also exhibited higher overall microbial richness. These site- and host-specific patterns underscore the influence of anatomy, ecology, and physiology on microbiome assembly and point to the need for follow-up studies on functional implications for seal health.

📄 (Under review - Submitted to The Royal Society Proceedings B in July 2025) 

This project examined the genital bacteriome of adult female California sea lions (Zalophus californianus) in the Gulf of California to explore its potential role in urogenital carcinoma (UGC) risk. Although UGC is common in stranded sea lions along California, it has not been documented elsewhere, and premalignant epithelial changes have been linked to organochlorine burdens and OtHV-1 infection—but the contribution of bacterial communities remained unstudied.

The study sampled genital swabs from sea lions at multiple sites throughout their Gulf of California range to assess spatial variation, compare healthy versus altered epithelia, and evaluate differences associated with OtHV-1 or papillomavirus infection. High-throughput 16S rRNA sequencing identified 2,270 ASVs, of which 35 comprised the core bacteriome, dominated by Fusobacteriia and Clostridia, with Actinobacteria, Alphaproteobacteria, and Campylobacteria also prevalent.

Alpha diversity and overall abundance varied geographically, and shifts in bacterial classes corresponded to epithelial status and inflammation—Fusobacteriia, Clostridia, Campylobacteria, and Alphaproteobacteria driving these differences. OtHV-1–positive samples exhibited the lowest diversity and abundance, whereas papillomavirus–positive samples showed the highest. This represents the first investigation of bacteriome–epithelial status relationships in a wild marine mammal prone to cancer, laying groundwork for future work on microbial biomarkers of UGC risk.

-- READ THE FULL PAPER📄 -- (Published in Infection, Genetics and Evolution in September 2023)