Materials that hang on piles or separately in the water: we call them 'pile hulas' or 'pontoon hulas'.
These hanging structures are designed primarily to allow organisms to establish a foothold, providing 'safe havens' for what crawls or swims around them. They are underwater structures made from concrete and nylon that provide a home for species such as mussels, sea squirts and sponges that filter the water and improve water quality. This is a great place for fish, not least because this rich environment is an excellent feeding ground.
In the current infrastructure setting of urban or port areas, the restoration of the original natural features is only possible to a limited extent. The natural function of a harbour basin can be enhanced using simple resources such as artificial hanging substrates of varying forms and materials.