New research from the Roberts Lab reveals that immune “training” in adult oysters can reshape how their offspring grow, metabolize energy, and survive extreme heat.
Marine heatwaves and disease outbreaks are increasingly hitting oyster farms and wild populations at the same time. For Pacific oysters (Magallana gigas), this deadly combination often shows up as summer mortality events, when up to 90% of animals can die in a matter of days. But what if oyster parents could “prepare” their offspring for these stressful conditions before they are even born?
A new study from our lab, led by Madeline Baird and Ariana Huffmyer provides exciting evidence that they can.
Training oyster parents’ immune systems
In this study, adult Pacific oysters were briefly exposed to Poly(I:C), a harmless synthetic molecule that mimics viral infection and activates the oyster immune system. This kind of immune priming has been shown to increase disease resistance in oysters—but here we asked a different question:
Does immune priming in parents change how their offspring handle heat and metabolic stress?
After the exposure, oysters were spawned, and their larvae were reared in commercial hatchery conditions and then grown into seed oysters over several months. These offspring were later tested for growth, survival under heat stress, and metabolic performance.
Faster growth in primed families
The first surprise was growth.
Although offspring from primed parents were slightly smaller early on, they grew faster over time and ended up larger than controls by 236 days post-fertilization. In other words, immune priming in parents altered how energy was allocated during development—suggesting a shift in developmental strategy.
This matters for hatcheries, where faster-growing seed often perform better during nursery and grow-out phases.
Heat survival depends on how hot it gets
Next, the team exposed oysters to temperatures ranging from normal conditions to extreme heat (up to 45°C) and measured survival.
The results were strikingly temperature-specific:
At 40°C, offspring from primed parents were 35% more likely to survive than controls
At 42°C, however, those same primed offspring were more likely to die than controls
This shows that immune priming doesn’t simply make oysters “tougher”—it reshapes where their thermal limits lie. In a warming ocean, that nuance matters.
Metabolism tells the story
Why did primed offspring survive better at 40°C but worse at 42°C? The answer appears to lie in their metabolism.
Using a high-throughput resazurin assay, the team measured how quickly oysters processed energy under different temperatures .
They found:
At 36°C, primed offspring had 43% higher metabolic activity than controls
At 40°C, primed offspring showed lower metabolic activity than controls
This pattern suggests that immune priming increases metabolic flexibility—the ability to ramp metabolism up under moderate stress and suppress it when conditions become extreme. That flexibility is likely what allows primed oysters to survive better at 40°C by entering a kind of protective metabolic slowdown, a known survival strategy in stressed marine invertebrates.
A form of environmental memory
These effects persisted for more than seven months after fertilization, long after early maternal provisioning should have faded. This points to deeper mechanisms of environmental memory, potentially involving:
altered maternal lipid and energy provisioning
immune-related transcripts passed into eggs
changes in microbiomes
epigenetic regulation (DNA methylation, non-coding RNAs)
Together, these mechanisms may allow oysters to transmit information about parental stress environments directly to the next generation.
What does this mean for aquaculture?
This research opens the door to a new idea:
Hatcheries could condition broodstock before spawning to improve offspring performance.
Because Poly(I:C) can be delivered by simple immersion, it could be integrated into existing hatchery workflows as a scalable, non-invasive treatment. When paired with selective breeding, immune priming might help produce oyster seed that is more resilient to heatwaves and disease—two of the biggest threats to modern shellfish farming.
At the same time, the study makes clear that priming is not a magic bullet. Benefits depended strongly on temperature, and extreme heat erased them. Field trials and longer-term studies are needed before these tools can be used widely.
Why this matters
As oceans warm and pathogens spread, oysters are being pushed toward their physiological limits. This study shows that parents matter—and that immune experiences in one generation can shape how the next generation grows, survives, and uses energy.
That’s environmental memory in action.
And it may become one of our most powerful tools for building climate-resilient aquaculture in the decades ahead.
📚 Reference
Baird M, Huffmyer AS, Ozguner N, Roberts SB. Parental immune priming reshapes offspring growth, metabolism, and thermal tolerance in the Pacific Oyster. bioRxiv. https://doi.org/10.64898/2025.12.10.693539