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Perch study impacts consumption advisories

May 28, 2013 — White perch are a popular catch in the Delaware River and Delaware Bay, but contaminants can make the fish unsafe to eat. Officials advise against eating white perch caught north of the Chesapeake and Delaware Canal and limiting consumption of those from south of the canal.

The trouble is, the fish can swim through that border.

“That’s just a rough guideline,” said Patrick Gaffney, professor of marine biosciences in the University of Delaware’s College of Earth, Ocean, and Environment. “It doesn’t really take into account the fact that there may be some populations that are really free of contaminants and others that are not.”

Gaffney and recent graduate Megan Shaffer have been working to identify distinct subpopulations of white perch in the Delaware Bay Estuary using genetic techniques. The different groups may vary in toxin levels depending on where they travel — and possibly be safer to eat than current advisories indicate.