Utilizing side scan sonar as an artificial reef management tool

Artificial reefs generally occur over broad areas of water bottoms, which is a challenge for artificial reef managers. These man-made habitats must be monitored to ensure compliance with U.S. Corps of Engineering permits and navigational clearance. Side scan sonar can map large areas relatively quickly. Side scan images can provide detailed information on latitude and longitude, orientation of reef material, relief of material, footprint and scouring around the reef material. The artificial reef can be scanned over time to determine the degree of stability (movement or subsidence) and durability (degradation of reef material). A total 150 nautical miles of transects have been surveyed to date. These transects cover approximately 6000 acres of water bottoms. In Mississippi, side scan sonar is utilized to detect movement of deployed material, subsidence of deployed material as well as provides accurate locations of all deployments surveyed. Accurate mapping of the deployments has allowed reef managers to begin strategically placing materials along a hierarchical design that Japanese researchers have found to be most productive habitat for reef fish.