Food systems are a major driver of climate change, as well as the loss of biodiversity globally. Therefore, the need to transform food systems has never been as urgent as now. Blue Foods - that is algae, macrophytes, shellfish, and fish harvested in marine and freshwater ecosystems - is seen as a sustainable healthy alternative source of proteins and nutrients to over 3.2 billion humans. This is particularly important for coastal communities of low- and middle-income countries, usually working in small scale systems. In the era of climate change, the collapse of fisheries stocks and the environmental issues caused by aquaculture call for the expansion of sustainable food production systems, even better if relying on environmentally friendly, ecosystem-based culture and/or extraction of blue foods, such as shellfish.
Within this global effort to shift food production systems, the present study was undertaken to assess the bivalve stocks available for exploitation and culture in a hyper arid RAMSAR wetland ecosystem in North Africa. We assessed, quantified, and mapped a series of variables, including the general biodiversity as a mirror of the health of the wetland ecosystem, the local pollution as a proxy of the overall water-sediment quality, and the major environmental factors that affect bivalve stocks, such as temperature, salinity, and hydrodynamics.
The results revealed that 9 species of bivalves are available in the area. Their stocks and distributions, however, were variable and depended mainly on temperature, salinity, and hydrodynamics. Among them, 3 species of bivalves had the highest potential for fisheries and aquaculture. All species, however, showed negative allometries, which reflects major perturbations in the environmental factors, i.e. high temperature and high salinities associated with a hyper arid climate, as well as climate change. In addition, altered hydrodynamics favor continuous deposition and shifting of coastal sediments, concomitant to altered water exchange with the Mediterranean open sea at the East and with the Boughrara lagoon at the West of the wetland.
Climate change and coastal ecosystem alterations related to a change in the land use-land cover on the island bordering the wetland in the north are expected to have an impact on bivalve stocks available as a sustainable blue food (fisheries and aquaculture development) for coastal communities, notably women who are engaged in the shellfish industry, living at 20% in acute poverty and poverty in a region battered by climate change and economic instability. Future studies of the feasibility of developing integrated shellfish-based production systems should be undertaken.