Oyster aquaculture in the Chesapeake Bay is a rapidly growing industry, contributing to both ecosystem restoration and economic growth. In the past decade, Maryland’s oyster industry has increased tenfold, providing economic opportunity for coastal communities. These coastal environments are dynamic and while oysters have evolved to cope with environmental variation, long exposures to stressors like low salinity and dissolved oxygen increase mortality and reduce growth and reproduction. Climate change and other anthropogenic impacts (i.e. land-use change, nutrient loading, etc.), exacerbate the intensity and frequency of these exposures which threatens the consistency of aquaculture production and the ecosystem services of farmed oysters.
Stress priming is a strategy by which an organism receives a sub-lethal dose of stress to bolster tolerance to future stress exposures. Based on studies conducted on various taxa, this tactic heightens cellular defenses by inducing frontloading of stress-related genes and causing epigenetic modifications that provide protection during subsequent stress events. While promising, the effectiveness of this environmental stress mitigation tool has not been tested on the eastern oyster. If applicable, this approach could be useful for protecting oyster crops during particularly vulnerable early life stages.
To evaluate the potential for stress priming to be an effective tactic to safeguard juvenile oysters from unexpected low salinity and low dissolved oxygens events, controlled lab experiments were conducted using these stressors. Initial experiments established the intensity and duration necessary to produce a priming effect for low salinity. Preliminary results found that shorter primes (12 hours - 2 days) at 2ppt had less mortality (8.8-11.2%) than a control group (24%) during a long-term stress exposure. Subsequent experiments utilized the most effective prime from the initial round, introduced hypoxia as an additional stressor, and tested both diploid and triploid oysters. Ongoing data analysis includes comparing growth and mortality data as well as processing samples collected for transcriptomic analysis using both existing biomarker tools and RNA sequencing. This study aims to provide insights into the effectiveness of stress priming on juvenile eastern oysters and improve understanding of the molecular underpinnings of the stress response among different stressors and oyster ploidies. The findings may inform future strategies for oyster aquaculture management in changing environmental conditions.