The Collaborative International Dictionary of English v.0.48:

aquaculture \aquaculture\ adj.
   1. the cultivation of aquatic animals, such as fish or
      shellfish, or of plants, such as seaweed, in a controlled
      and sometimes enclosed body of water. The term includes
      use of either salt or fresh water. It is a form of
      agriculture, but under water.
      [PJC]

WordNet (r) 3.0 (2006):

aquaculture
    n 1: rearing aquatic animals or cultivating aquatic plants for
         food