Results and discussions
In Korea, harvesting activities on tidal flat are handed down among people as marine culture (Ministry of Oceans and Fisheries, 2002a). Fishing gears used in tidal flats are divided into four different categories: (1) collection tools, (2) de-shelling tools, (3) containers, and (4) carrying tools (Fig. 3). As of oyster collection, there is one more category of tools used for water draining after de-shelling.