Fish Acquisition and Consumption in the African Great Lakes Region through a Food Environment Lens: A Scoping Review.

Effective actions for the fishery and aquaculture sectors to contribute toward improving nutrition rely on an understanding of the factors influencing fish intake, particularly amongst vulnerable populations. This scoping review synthesises evidence from 33 studies in the African Great Lakes Region to examine the influence of food environments on fish acquisition and consumption. We identified only two studies that explicitly applied a food environment framework and none that linked policy conditions with the contribution of fish to diets. Economic access to fish was represented in the largest number of included studies (21 studies), followed by preferences, acceptability and desirability of fish (17 studies) and availability and physical access (14 studies). Positive perceptions of taste and low cost, relative to other animal-source foods, were drivers of fish purchases in many settings; however, limited physical and economic access were frequently identified as preventing optimal intake. In lakeside communities, fish were increasingly directed toward external markets which reduced the availability and affordability of fish for local households. Few studies considered intra-household variations in fish access according to age, gender or physiological status, which represents an important knowledge gap. There is also scope for future research on seasonal influences on fish access and the design and rigorous evaluation of programmes and policies that address one or more constraints of availability, cost, convenience and preferences.

Confronting the realities of wastewater aquaculture in peri-urban Kolkata with bioeconomic modelling.

Wastewater reuse for aquaculture is a reality in several Asian countries, however, traditional practices face constraints including inadequate or contaminated wastewater inputs and growing concern over health risks. Based on Kolkata and a wastewater flow of 550,000m(3)d(-1), rational and conventional designs for lagoon-based wastewater treatment and reuse through aquaculture were compared using bioeconomic modelling. Outcomes showed the rational design required a larger area than the conventional or traditional systems, but that financial returns, nutrient retention and fish production were higher; gross fish production employing rational and conventional designs was 45,500 and 11,560t, respectively. However, limited land availability and constraints to reconfiguring the existing system make implementation of the rational design unlikely. Findings suggest traditional practices could be enhanced by adopting wastewater treatment prior to reuse, modifying fish production strategies, and monitoring to safeguard health. Bioeconomic modelling constitutes a useful tool in comparing treatment and reuse options, permitting the sensitivity of financial returns to changing costs and recent revisions to WHO guidelines for safe wastewater reuse to be assessed, however, social and environmental consequences demand consideration.

Can greening of aquaculture sequester blue carbon?

Globally, blue carbon (i.e., carbon in coastal and marine ecosystems) emissions have been seriously augmented due to the devastating effects of anthropogenic pressures on coastal ecosystems including mangrove swamps, salt marshes, and seagrass meadows. The greening of aquaculture, however, including an ecosystem approach to Integrated Aquaculture-Agriculture (IAA) and Integrated Multi-Trophic Aquaculture (IMTA) could play a significant role in reversing this trend, enhancing coastal ecosystems, and sequestering blue carbon. Ponds within IAA farming systems sequester more carbon per unit area than conventional fish ponds, natural lakes, and inland seas. The translocation of shrimp culture from mangrove swamps to offshore IMTA could reduce mangrove loss, reverse blue carbon emissions, and in turn increase storage of blue carbon through restoration of mangroves. Moreover, offshore IMTA may create a barrier to trawl fishing which in turn could help restore seagrasses and further enhance blue carbon sequestration. Seaweed and shellfish culture within IMTA could also help to sequester more blue carbon. The greening of aquaculture could face several challenges that need to be addressed in order to realize substantial benefits from enhanced blue carbon sequestration and eventually contribute to global climate change mitigation.