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Catfish Impact on Crab Population Studied

US - The effect that in creasing numbers of blue catfish are having on crab populations in rivers in Virginia is the subject of a study by scientists at the Virginia Department of Game and Inland Fisheries (VDGIF) and the Virginia Institute of Marine Science (VIMS).

The Virginia Department of Game and Inland Fisheries (VDGIF) introduced the Mississippi native blue catfish into the three primary rivers of the Commonwealth back in the early 80's.

Scientists admit that it has proliferated wildly and that it will eat virtually anything, including mud according to a report in Northern Neck News.

"It is extremely abundant," said Bob Greenley, VDGIF marine scientist told the newspaper.

"They will eat anything. Anybody that works the tidal rivers and sees the abundance of catfish has concerns."

Greenley was one of the principal scientists, along with Rob Latour and Rom Lipcius of the Virginia Institute of Marine Science (VIMS) and at what Greenley called "the first formal discussion" of the catfish's impact on the crab population on May 20 at the Virginia Department of Marine Resources (VMRC).

Also present at the meeting was Warsaw waterman and president of the Twin Rivers Waterman's Association, Doug Jenkins.

He has long been proclaiming the rampant predation of the catfish on the crab population in what scientists call the overlap areas, Northern Neck News reports.

Those are areas of the three Virginia rivers, the James, Rappahannock and York, and the Potomac River where the freshwater catfish population, which can tolerate salinity levels of up to about 12 parts per million, overlaps with the saltwater crab population.

Crabs migrate farther up the rivers in drier weather, which increases the salinity farther up river, and the catfish migrate farther down river in wetter weather, which has the reverse effect.

"The science that has been done up to this point shows that the overlap area is growing," said Greenley.

"Crabs are moving up the rivers."

View the Northern Neck News story by clicking here.