PROBLEM TO BE SOLVED: To provide an environmental preservation vessel for water area able to easily add or exchange solely a fertilizing material and promote growth of marine organisms by preventing scattering of the fertilizing material and maintaining fertilizing effect for a long period of time, and provide an environmental preservation system for water area and a method for preserving water area environment. SOLUTION: The fertilizing material 3 containing steel slag or a water-permeable bag filled with the fertilizing material 3 is housed in the vessel 2a whose top is open or a vessel 2b having≥1 holes 4. Here, the ratio of a maximum length d of the top of the vessel 2a over a depth D from the top to a surface of the fertilizing material 3 (D/d), or the ratio of a maximum length d of the hole 4 made on the vessel 2b over a depth D from the hole to the surface 3 of the fertilizing material (D/d) may satisfy≥0.2. COPYRIGHT: (C)2008,JPO&INPIT
