The acoustic detection and characteristics of sublittoral bivalve reefs in the Bay of Fundy

Bivalve reefs are universal topographic features of the continental shelf benthic environment at depths which may exceed 100 m. The use of modern acoustic survey methods (sidescan sonar and high-resolution seismic reflection systems) within the Bay of Fundy located novel, flow-parallel bioherms tentatively identified as horse mussel, Modiolus modiolus, reefs. We show, using a remote operated vehicle (ROV) on which a color video camera was mounted, that the acoustically identified features are indeed horse mussel reefs. Their linear shape, distribution and orientation suggest a dominant control by strong tidal currents.