Oysters play unexpected role in protecting blue crabs from disease

by John Wallace, Virginia Institute of Marine Science
February 3, 2026

Oysters famously filter their surrounding water, but it turns out they are removing more than algae and excess nutrients. New research from William & Mary’s Batten School of Coastal & Marine Sciences & VIMS shows they can also reduce the spread of disease in nearby marine species, including Chesapeake Bay’s prized blue crabs.

Recently published in the journal Ecology, the study found that oyster filter feeding significantly reduced the transmission of Hematodinium perezi, a deadly parasite that commonly infects juvenile blue crabs in high-salinity coastal waters. In field experiments conducted on Virginia’s Eastern Shore, juvenile crabs placed near live oysters were about one-third less likely to become infected than crabs deployed without oysters.

“We know that oysters and oyster reefs provide a variety of ecological benefits, and that crabs are drawn to them for food and protection, but their ability to remove pathogens from the environment has not been well studied,” said Jeffrey Shields, a professor at the Batten School & VIMS who worked with his graduate student and several undergraduates on the study, including lead author Xuqing Chen, Ph.D. ’25.

Keep reading: https://www.vims.edu/newsandevents/topstories/2026/ecology-oysters-filter-disease.php

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.70281