Cultch is a common term in aquaculture that refers to any material used to promote the growth of shellfish by providing a hard substrate for them to attach onto. However, there are several other synonyms that can be used in place of cultch such as oyster substrate, seed, spat collector, or shellfish bed. These terms are used interchangeably to describe various materials like crushed shells, pebbles, tiles, and even plastic meshes that can be placed in the water to support the growth of shellfish. Regardless of which term is used, all of these materials play an important role in the propagation of shellfish and the sustainability of the aquaculture industry.