Life cycle assessment of a novel closed-containment salmon aquaculture technology.

Abstract

In salmonid aquaculture, a variety of technologies have been deployed that attempt to limit a range of environmental impacts associated with net-pen culture. One such technology employs a floating, solid-walled enclosure as the primary culture environment, providing greater potential control over negative interactions with surroundings waters while limiting energy use required for water circulation, thermo-regulation and supplemental oxygen provision. Here, we utilize life cycle assessment to model contributions to a suite of global-scale resource depletion and environmental concerns (including global warming potential, acidification potential, marine eutrophication potential, cumulative energy use, and biotic resource use) of such a technology deployed commercially to rear Chinook salmon in coastal British Columbia, Canada. Results indicate that at full grow-out, feed provisioning and on-site energy use dominate contributions across four of five impact categories assessed. For example, per tonne of salmon harvested, feed contributed approximately 72% to global warming potential, 72% to acidification potential, and accounted for 100% of biotic resource use. However, for both feed and on-site energy use, impacts are heavily influenced by specific sources of inputs; therefore efforts to improve the environmental performance of this technology should focus on reducing these in favor of less impactful alternatives.