Abstract: In the embodiments described in the specification an artificial reef is assembled from a plurality of superposed layers of modules having similarly shaped projections and recesses located at predetermined specific locations on top and bottom surfaces and having a continuous through hole extending through each module. The projections of modules in one layer are received in recesses of modules in an adjacent layer so that the through holes of the modules in adjacent layers are vertically aligned and continuous columns of concrete formed in the vertically aligned through holes unite the modules to provide a unified artificial reef.

Abstract: An artificial reef is assembled from modular units having mating projections and recesses and incorporating human cremain to provide a memorial for deceased persons in a marine environment. In one embodiment the human cremain is encapsulated in cavities within the module. In another embodiment, the human cremain is incorporated in a plaque mounted in an opening in the surface of the module.

Abstract: A synthetic habitat device providing for the enhancement of open estuary systems with regard to the survival potential of juvenile fish. The device is an assembly composed of a horizontal member with a plurality of cylindrical downward curving appendages. The device is permanently attached to existing bulkhead structures bordering an aquatic system and is located adjacent to and below the surface of the water at low tide elevation. The device provides substrate for colonization by marine organisms and sanctuary to juvenile fish in various developmental stages. The device is a substitute for indigenous plant structure and substrate which has been diminished or eliminated from a natural estuary system.