Rising global demand for seafood and declining catches have resulted in the volume of mariculture doubling each decade, a growth expected by the FAO to persist in the decades to come. This growth should use technologies with economical and environmental sustainability. Feed accounts for about half the cost in current high-volume fed mono-species aquaculture, mainly fish net pens or shrimp/fish ponds, yet most of this feed becomes waste. The resulting environmental impact and rising feed costs therefore hamper further growth of such farms. As in certain traditional polyculture schemes, plants can drastically reduce feed use and environmental impact of industrialized mariculture and at the same time add to its income. These nutrient-assimilating photoautotrophic plants use solar energy to turn nutrient-rich effluents into profitable resources. Plants counteract the environmental effects of the heterotrophic fed fish and shrimp and restore water quality. Today's integrated intensive aquaculture approaches, developed from traditional extensive polyculture, integrate the culture of fish or shrimp with vegetables, microalgae, shellfish and/or seaweeds. Integrated mariculture can take place in coastal waters or in ponds and can be highly intensified. Today's technologies are well studied and documented. They are generic, modular and adaptable for several culture combinations of fish, shrimp, shellfish, abalone, sea urchin and several species of commercially important seaweeds and vegetables. A 1-ha land-based integrated seabream-shellfish-seaweed farm can produce 25 tons of fish, 50 tons of bivalves and 30 tons fresh weight of seaweeds annually. Another farm model can produce in 1 ha 55 tons of seabream or 92 tons of salmon, with 385 or 500 fresh weight of seaweed, respectively, without pollution. Preliminary calculations show a potential for high profitability with large integrated farms. Several freshwater integrated fish-vegetable farms and a couple of modern fish-algae-shellfish/abalone integrated mariculture farms exist today, and several additional farms are planned. Three major international R&D projects promise to soon expand the horizons of the technology further. Therefore, modern integrated systems in general, and seaweed-based systems in particular, are bound to play a major role in the sustainable expansion of world aquaculture.
Bibliographical noteFunding Information:
(A) Supported by AquaNet, the Network of Centres of Excellence for Aquaculture, an interdisciplinary project, involving the University of New Brunswick, the Canada Department of Fisheries and Oceans, the Canadian Food Inspection Agency and several industrial partners, is developing an open-water integrated mariculture system in the Bay of Fundy, Canada. Salmon (Salmo salar), mussel (Mytilus edulis) and kelp (Laminaria saccharina) are being grown together at several industrial pilot-scale sites to develop an integrated aquaculture model and to train students and professionals in this innovative approach to aquaculture. The productivity and role of each component (fish, shellfish and seaweed) is being analyzed so that the appropriate proportions of each of them can be defined. The data are expected to help develop a sustainable system in which metabolic processes counterbalance each other within acceptable operational limits and according to food safety guidelines and regulations. The ultimate goal of this project is to transfer this model, of environmentally and economically balanced diversification and social responsibility, to other sites and make it a concept transferable to other aquaculture systems.
This work was supported by the Israeli Ministry for National Infrastructures, the Israeli Ministry of Industry and Commerce and several grants from the European Union (A.N. and M.S.), the Ministry of Science and Technology of Israel, Binational Israeli–American Fund for R&D in Aquaculture (BARD), and the Negev-Arava R&D Network (A.N.); the Natural Sciences and Engineering Research Council of Canada, AquaNet Network of Centres of Excellence for Aquaculture (T.C.; this paper is contribution no. 73 from the Centre for Coastal Studies and Aquaculture); the Fundación Terram (contribution no. 3 from i-mar) and the British Embassy, Chile (A.H.B); the Swedish International Development Cooperation Agency—SIDA (M.T. and C.H.); the State of Connecticut Critical Technology Grant Program, the Connecticut, New Hampshire and New York Sea Grant College Programs, and the National Marine Aquaculture Initiative of the Office of Oceanic and Atmospheric Research, NOAA-DOC, USA (C.Y., G.P.K. and T.C.). We are grateful to B. Scharfstein for the photograph and the information on the sea or Marine Enterprises form, to Kathy Chopin for her help with editing, and for the very constructive comments by several reviewers.
- Integrated aquaculture
- Modern mariculture
- Seaweed biofiltration
ASJC Scopus subject areas
- Aquatic Science