Aquafeed is the most resource and climate intensive part of farming Atlantic salmon in Tasmania. It has been found to have higher Global Warming Potential impacts than salmon farming in other countries such as Norway, Canada and the U.K. The CO2 equivalent emissions per kilo of salmon in Tasmania is up to four times more greenhouse intensive than in other developed countries with comparable salmon farming industries.
It is often cited that farming Atlantic salmon is a more sustainable means of producing animal protein than other forms of animal farming in Australia. Based on multiple studies outlined below Atlantic salmon farming in Tasmania has only marginally less global warming impact than farming beef cattle. This is in large part due to the greenhouse intensive way in which salmon feed is manufactured for the Tasmanian salmon industry.
An estimated 96% of the global warming impact of Tasmanian farmed Atlantic salmon is due to salmon feed. The primary production of the raw materials accounted for 91% of the global warming potential of salmon feed. This can be explained by the use of terrestrial animal products in Atlantic salmon feeds, particularly those taken from ruminant and other mammal species.
The use of chicken feathers, oil and meal was estimated to account for 26% of the global warming potential, largely due to the manure emissions in chicken sheds, and the climate impacts of globally sourced crops including soya, maize and wheat for poultry feeds chickens are raised on.
A large percentage of these terrestrial animal ingredients are by-products from highly carbon intensive livestock industries. While some would argue that greenhouse emissions from by-products are less concerning than those from purpose-grown ingredients, the use of these abattoir by products embeds the Tasmanian salmon industry deeply within the supply chain of the worst performing emitters.
Given the need for urgent greenhouse emissions reduction, this raises concerns about the future sustainabiliyt of Tasmanian aquafeed and precludes a simple statement that the industry is 'more environmentally friendly' than other greenhouse intensive agriculture.
Table 3. Comparison of global warming potential impacts of global salmon farming
* average (mean) of the six production systems analysed (min 10,100, max 12, 700)Table 4. Global warming potential of Tasmanian farmed salmon compared to other farmed animal proteins in Australia.
Table 5. Global warming potential of Tasmanian farmed salmon at various stages of production.