Environmental Accounting of the Yellow-Tail Lambari Aquaculture: Sustainability of Rural Freshwater Pond Systems

Freshwater pond aquaculture is the prevailing fish culture system worldwide, especially in developing countries. Climate change outcomes and inadequate environmental practices challenge its sustainability. This study applies emergy synthesis to assess the environmental performance of freshwater pond aquaculture in Brazil, aiming to identify and propose practices towards sustainability. As a study model, nine semi-intensive lambari farms operating at three levels of management were evaluated: low (LC), moderate (MC) and high (HC) control. Results showed that the main inputs for LC were services (27-46%), feed (7-39%), and water (15-21%), while for the MC and HC farms, they were feed (35-49% and 17-48%, respectively) and services (33-39% and 26-36%, respectively). All farms required more than 60% of their emergy from purchased inputs, resulting in low emergy sustainability index (ESI = 0.1-0.5). Replacing animal protein and oil on diet composition by vegetal sources, using superficial water instead of springwater, increasing juvenile productivity, and controlling pond fertilization can lead all systems to higher efficiency and resilience, increasing sustainability.

The Sustainability of Living in a “Green” Urban District: An Emergy Perspective

While urban areas hold great potential for contributing to sustainable development, there is a critical need to better understand and verify what measures improve urban sustainability. To achieve this, this project implements emergy synthesis to evaluate the environmental support to a building—called Smaragden—located in a certified “green” urban district in Uppsala, Sweden. Inputs to the building’s construction and maintenance phases are accounted for, as are flows supporting the residents’ everyday practices (i.e., urban life), on a yearly per capita basis. In this way, the relative importance of lifestyle issues versus the built environment is quantified and compared. Key focus areas are identified where efficiency and sustainability gains are most likely. The emergy synthesis detailed the top contributors to urban resource consumption and revealed that both the lifestyle and built environment in Smaragden are highly unsustainable, ranking poorly in terms of the emergy indices calculated, and, when considered from a global emergy perspective, overshooting resource consumption by more than 70 times. The paper therefore concludes that interdependencies of urban districts on systems at larger scales of society and environment need to be explicitly addressed and actively incorporated in urban policy and planning, and that design interventions are hence grounded in a systems perspective on urban sustainability.