Sustainability of Nile tilapia net-cage culture in a reservoir in a semi-arid region

Abstract

Among the tools used to measure sustainability in aquaculture, sets of indicators allow a holistic view of a system in its social, environmental, and economic dimensions. Approaches that align indicators with models such as the Drivers-Pressure-State-Impact-Response (DPSIR) framework can improve understanding of this sustainability. This study evaluated the sustainability of cage production systems for Nile tilapia in the Santa Cruz Reservoir, to determine whether a set of indicators used with the DPSIR conceptual model was effective to study the sustainability of the system. The 49 indicators used were calculated from information obtained from questionnaires and from monitoring the production system. Sustainability was also modeled and compared with hypothetical scenarios, with different fish stocking densities. The results indicated that the production system is economically feasible, generating profit and distributing income. However, the income generated benefits few people and is not fixed in the community. Environmentally speaking, the system is highly dependent on inputs, especially the nutrients nitrogen and phosphorus, and energy, as well as increasing sedimentation of nutrients in the reservoir. In the social dimension, the venture employs few workers. The modeling showed that the system is potentially sustainable, and that changes in stocking density decreased this sustainability. In summary, the system showed many sustainable features, whereas some others need to be modified to improve the general sustainability.

Fisheries or aquaculture? Unravelling key determinants of livelihoods in the Brazilian semi-arid region

“…Again, this also depends on cage density and their stocking, and on the reservoir depth and its connectivity with other water bodies. Studies with cage and pond tilapia farms in Ethiopia and in Brazil, for example, have hardly shown any evidence of a higher concentration of nutrients in the water (Degefu, Mengistu & Schagerl, ; Moura et al., ). In fact, tilapia could be used to control cyanobacteria blooms that can affect human health (Attayde, van Nes, Araujo, Corso & Scheffer, ; Tucker, ).…”

“…The Santa Cruz reservoir was filled in 2002, and it is the second largest in the state. It can store up to 600 million m 3 of water (Moura et al., ), irrigates just little over 14.000 ha and serves 108.000 people in 27 municipalities. The Umari reservoir was also filled in 2002 and is the third largest in the state.…”

“…In Brazil, the practice of aquaculture can be found in places as diverse as the Amazon (Gomes et al., ) and semi‐arid regions (Albinati, ; Moura, Valenti & Henry‐Silva, ). In the latter, reservoirs created primarily for drinking water and for agriculture and animal husbandry are also used for cage aquaculture, especially for the exotic Nile Tilapia ( Oreochromis niloticus Linnaeus).…”

Food web and ecological models used to assess aquatic ecosystems submitted to aquaculture activities

“…However, among the main anthropic impacts assessed, the effects of aquaculture activities are among the least studied, especially in tropical environments, as can be observed in the survey performed for EwE (COLLÉTER et al, 2015). One of the major challenges today is to measure how much an aquatic ecosystem can support in terms of cultivated organisms, aiming to maintain the environmental, social, and economic sustainability of aquaculture activities (MOURA et al, 2016). Regarding this issue, mathematical modelling has been successfully used in order to determine the support capacity of systems with respect to cultivated species.…”

Aquaculture expansion in Brazilian freshwaters against the Aichi Biodiversity Targets

“…We recognize the importance of aquaculture for food security and income (Pant et al 2014;Moura et al 2016).…”