An experiment for evaluating the best substrate for collecting Crassostrea rhizophorae spat, using plates of asbestos-cement, rubber tire tubes, oyster shells, plywood, plastic bottles and plexiglass, was carried out from March to April 1984 (dry season) in Estero Vizcaya, Limón, Costa Rica.

The plexiglass and plastic bottles were more efficient for removal of small oyster seed, and asbestoscement and rubber tire tubes gave the best results for oyster settlement per m2. Settlement of undesirable organisms was greater on asbestos-cement and oyster shells than on the other substrates.