Any marine bivalve mollusk of the Family Ostreidae, usually found adhering to rocks or other fixed objects in shallow water along the seacoasts, or in brackish water in the mouth of rivers.
Even as recently as 1947, out of 35,000 oysters harvested by a crew in one week, only 21 bore a pearl treasure, and of these, only 3 were of marketable quality.
Researchers are hoping that a nontoxic Teflon-based coating will solve the problem, since barnacles could then be simply brushed off the hulls, and the oysters would not be harmed.