Protecting Oysters from Burrowing Shrimp

For members of the multimillion-dollar West Coast shellfish industry, their world is the oyster.

Unfortunately, the oyster industry's ability to meet rising demands is hampered by two species of burrowing shrimp. So Agricultural Research Service (ARS) scientists are collaborating with colleagues from Washington State University and Oregon State University to develop sustainable shrimp-control strategies.

Ghost shrimp and mud shrimp inhabit the tideflats in estuaries where West Coast oysters are raised. The shrimp burrow into the estuaries, making the intertidal mud soft and unstable. As a result, oysters and other shellfish can sink beneath the silty surface and suffocate.

Brett Dumbauld, an ARS ecologist stationed in Newport, Ore., and his colleagues are uncovering information about the shrimps' habitats, life history and natural predators—information that can be used to help develop new methods to protect oysters from pests.

The scientists showed that ghost and mud shrimp may be most vulnerable to control directly after "recruitment," when an influx of young shrimp enters the estuaries. At this point, the shrimp live in small burrows near the surface, where they are potentially more vulnerable to predators and other treatment measures.

Dumbauld examined several shrimp populations in Washington and Oregon estuaries and observed wide fluctuations in the number of young shrimp returning each year. This is significant because being able to predict high recruitment could impact the effectiveness of control strategies by improving the timing, intensity and targeting of treatment.

Dumbauld is also collaborating with scientists at the U.S. Environmental Protection Agency's Pacific Coastal Ecology Branch to create maps that will help scientists determine how shrimp populations are distributed and whether control measures can be more effectively deployed on a large scale. This type of information is critical to developing successful integrated pest management strategies.

Read more about the research in the May/June 2008 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.