THE EFFECTS OF STRESS ON EASTERN OYSTERS (CRASSOSTREA VIRGINICA) FOLLOWING EXPOSURE TO MUD CRAB (PANOPEUS HERBSTII) PREDATOR CUES

Eastern oysters (Crassostrea virginica) provide essential ecosystem services and support the multimillion-dollar shellfish industry, yet their interactions with predators, such as mud crabs (Panopeus herbstii), and resulting impacts on restoration success remain underexplored. We investigated the effects of exposure to mud crab predator cues on oyster stress responses, including changes in cortisol (a stress hormone), microbiome composition, and short-term survivorship. Hatchery-raised oysters, naïve to predators, were exposed to mud crab cues in a 28-day aquarium-based experiment. Oysters and crabs were housed in separate tanks. Weekly, 1L of water from each oyster tank (n=3 per treatment) was removed and replaced with either filtered hatchery water or a 1:1 mixture of hatchery and predator tank water—containing predator-exuded compounds. Oysters (n=9 per treatment) were sampled immediately prior to water changes. Predator cue exposure resulted in an initial spike in cortisol, which diminished over time, while oyster survival remained unaffected. Preliminary microbiome analysis of predator cue-exposed oysters using 16S rRNA gene sequencing revealed shifts in bacterial communities, with an increase in both beneficial taxa (e.g., Endozoicomonas) and opportunistic pathogens (e.g., Shewanella, Arcobacter). Overall, we demonstrate that while predator presence induces stress and alters microbiome composition, it does not significantly impact oyster survival under controlled laboratory conditions, suggesting that predator cues alone are unlikely to impede restoration efforts.

Presentation Preference: Poster

Primary Presenter: Estelle Fisher, Washington & Lee University (fishere25@mail.wlu.edu)

Authors:

Rebecca Goldman, Washington & Lee University  (rgoldman@mail.wlu.edu)

Joseph Reustle, Hampton University  (joseph.reustle@hamptonu.edu)

Kelly Bezold, Washington & Lee University  (bezoldk@wlu.edu)

Alicia Reigel, Washington & Lee University  (areigel@wlu.edu)