This document discusses the blue revolution, which refers to the rapid expansion of intensive commercial aquaculture beginning in the 1970s. It defines aquaculture as the cultivation of aquatic populations under controlled environments for human consumption. While aquaculture has advantages like providing food and economic benefits, it also has disadvantages such as pollution, disease risks, and negative social impacts including displacement of local farmers. The document examines case studies of aquaculture development in Japan and Bangladesh and challenges facing further expansion, such as overfishing, bycatch, and pollution.