A modular agriculture system for use underwater. The system comprises a plurality of node elements 101 each including an agricultural unit and a plurality of connection elements 201 for inter-connecting at least some of said nodes to form a mesh-like structure with nodes at the mesh junctions. A significant portion of said connection elements are of low cross section such that when in use and placed underwater they present a low resistance to the action of waves and currents. A plurality of tensioning elements (figure 1 ref 310,320) are connected to the mesh-like structure to place the connection elements in tension and at least two anchor elements (figure 1, ref 301) for securing the structure to the sea bottom. The node elements may contain means such as cages 601 to control pests.
