The Current: Researcher Battles Disease in Growing Industry
Written by Sam Costello, with photos by Carrie Byron
The U.S. aquaculture industry - businesses that farm fish, shellfish, and other marine life for food - generates nearly $1 billion annually. Oysters are among the largest slices of this market, but in Rhode Island, the $2 million oyster industry could be damaged by disease and climate change. But the industry isn't facing these threats alone.
Kate Markey, Professor Marta Gomez's student
Changing Industry, Changing Climate
While Rhode Island's current oyster production is relatively small, the state's history with the mollusk dates back over 100 years to when a third of the Narragansett Bay was devoted to oyster cultivation. Farmers and scientists have contributed to a resurgence in recent years (for more, see "The Freelance Troubleshooter" in The Current #2).
The fledgling industry could be threatened by disease and climate change, though, and that's where Marta Gomez, a professor in the Department of Fisheries, Animal and Veterinary Science at the University of Rhode Island (URI), and her colleagues come in.
Gomez, a Spaniard who has been at URI since 1997, studies the three major diseases affecting Rhode Island's indigenous oyster, the American, or Eastern, oyster:
- Dermo - a parasite affecting the shells of adult oysters
- MSX - this parasite attacks oysters more quickly than Dermo
- Juvenile Oyster Disease - a bacteria that targets young oysters under an inch in length. This disease has been seen to kill up to 90% of a farm once present.
All three diseases flourish in warm summer and fall waters. In this way, climate change - and the warming of ocean temperatures brought on by it - compounds the threat to oysters posed by these diseases.
When waters are warmer longer, oysters are exposed to the diseases for longer periods, with potentially deadly consequences. This has been especially true for Dermo, Gomez says, which has seen an expansion in its geographic range in recent years.
"The expansion of the range of the disease is related to warmer winter temperatures," she says, since the warmer temperatures allow the parasite to live, and move north, longer into the year than in the past.
Building a Better Oyster
Gomez and her colleagues are responding to the twin threats of disease and climate change by working with the local industry to develop oysters that are resistant to the diseases.
"After we know what diseases are prevalent, we try to figure out what tools are available to prevent them," she says.
Those efforts include new cultivation methods to address the changing disease environment and engineering disease-resistant oysters.
Disease resistance can be developed through the counter-intuitive move of exposing oysters to disease. While the disease will infect and kill some, the oysters that are infected but survive can be used the following season to promote a population with resistance to the disease.
This method has its downsides, though, so Gomez and her colleagues are using a lab-based process called "marker-assisted selection" to identify what genes confer disease resistance.
"If we know what molecules are linked to disease resistance, we can look for oysters with those molecules," she says.
Key to this work are the modern research facilities at URI - including the RI NSF-EPSCoR supported Flowing Seawater facility at the Graduate School of Oceanography and the Genomics and Sequencing Center - facilities that are part of Rhode Island's increasing commitment to the life sciences.
Kate Markey, Professor Marta Gomez's student
More Capacity Generates Better Research
The increased robustness of local research facilities isn't the only thing helping Gomez. Having more colleagues is also a major asset.
When Gomez began at URI in 1997, she was the sole researcher in her area, so she had to perform many administrative tasks herself. That's changed with the expansion of these programs and the arrival of RI NSF-EPSCoR.
RI NSF-EPSCoR has funded the hiring of genomics and ecology researchers, two disciplines that provide crucial, complementary knowledge for Gomez's work.
"Having a bunch of people that have different intellectual expertise that have a common interest in disease in the marine environment provides critical mass so that you can get more done," she says.
That critical mass allows researchers to focus more on their research.
"EPSCoR has provided a lot of tools and a lot of people, so you can worry about the big questions and be more ambitious in your research," she says.
With institutional supports and complementary researchers in place, Gomez and her colleagues are poised to address the diseases and other threats to Rhode Island's aquaculture industry and the oysters that are a growing part of it.