Shrimp aquaculture has expanded rapidly in all of the world, especially in tropical areas. Shrimp ponds have traditionally been constructed near estuarine zones, especially in wetlands and mangrove swamps, creating a concern with environmental impacts, since it may cause the destruction of large areas of mangrove forests. Consequently, the expansion of the shrimp industry has some limitations. Moreover, the construction of residential and tourist enterprises has contributed to the high economic valorization of marine coastal lands, and also limits aquaculture development in some countries. Cage aquaculture has been studied by some investigators as an alternative for rearing shrimp Meanwhile, there has been some speculation on the use of this technique as an attempt to reduce the social and environmental impacts of the shrimp industry. Culturing seaweed inside shrimp cages can increase the economic output for both organisms. Seaweed can play a role as a natural substrate, providing shade, shelter, and also bedding for other small organisms, which may improve the natural source of live food for shrimp. In addition, cage culture can prevent herbivorous fishes from grazing on the farmed seaweed, and can even serve as a container, preventing occasional losses that may occur when the plant branches accidentally break off. Another positive aspect of incorporating seaweed into an integrated polyculture system with shrimp is the role that such organisms can have as “nutrient scrubbers” (Hanisak, 1998), working as natural filters for soluble wastes from aquaculture facilities (Troell et al., 1999). This integration,
therefore, may reduce the environmental impact of shrimp aquaculture. Some studies have been carried out with the purpose of employing an integrated system (with seaweed) for removing nutrients from mariculture ponds and cage
effluents The Philippines seaweed Kappaphycus alvarezii has been successfully introduced in tropical areas, resulting in
a high potential for biomass production. The major commercial value of this seaweed is related to the carrageenan
production (a complex phycocolloid highly utilized especially by the food and cosmetic industries). Yarish et al. (2001) refer to the high capacity of K. alvarezii in removing nitrogen and phosphorous from coastal embayments and refer to the importance of integrating seaweed culture with other mariculture activities. The present study was carried out to test the technical feasibility of co-culturing the Pacific white shrimp Litopenaeus vannamei and the Philippines seaweed K.
alvarezii inside the same floating cage.