An excellent first draft. Specific comments:
1. Within the key aspect of environmental sustainabilty there is no mention of the area that aquaculture will operate in in future although this is mentioned for capture fisheries: in land or inland and marine waters, in natural ecosystems or human-made agro-ecosystems. I addressed this issue in a keynote recently presented at the Elsevier conference in Las Palmas, Gran Canaria in November, which will be published early next year (abstract attached). Inland aquaculture is likely to continue to be the major source of fish rather than mariculture through both intensification and expansion of farmed area. Although there are limits to land and water, a recent paper by Boyd and Brummett (2012) has indicated that 'renewable freshwater appears adequate for considerable expansion of aquaculture, especially outside Asia'. A significant amount of inland aquaculture production takes place in ponds converted from rice fields and this trend is likely to continue as aquaculture is a more efficent use of land and water, especially than low-yielding rice fields. Isupport the call in the Recommendations for studies on the most efficient use of land and water resources. Research is certainly required on the merits of conversion of the realatively small area of rice fields, especially low-yielding ones, that would be needed to meet the predicted 2050 demand for fish.
2. You cite me several times in Section 3.7 times, although the references are not listed, as well as Little and Edwards (2003) that livestock manure 'supports the production of most cultured fish in Asia'. This is not true anymore as there has been a major delinking of integrated livestock and fish. The recent rapid increase in aquaculture production has been through intensification using agro-industrial pelleted feed. Total production of pelleted feed increased more than 3 times from 7.6 million tonnes in 1995 to 27.1 million tonnes in 2007 and is expecyed to reach 70.9 million metric tonnes by 2020 (Tacon et al.2012).
3. In Section 3, the poor eat tilapia as well as carps and catfish.
A plant-based diet may not lead to amino acid deficiency e.g. amino acid complementarity in Latin America where the basic diet is not mainly grain but maize and beans.
Peter Edwards