Awesome video, PGW! Where did you find it? Amazing! There is a Bogue Island in North Carolina, but I found this on the internet:
Isognomon alatus (flat “oyster”): Reported to occur naturally in Oyster Bay, Falmouth; Bogue Island, Montego Bay; Port Royal, Kingston and Drainage Channel, St. Thomas. The two members of the study group saw thick clusters of these oysters attached to poles and mangrove roots in a tidal creek at Green Island. A literature survey has not revealed any reports of commercial or experimental culture trials. On the north coast the flat oysters are collected and sold fresh or pickled in brine.
FROM: http://www.fao.org/docrep/006/q5739e/Q5739E15.htm
Huh! Who knew?