Thank you for your interest and for the invitation to appear here. This is the first time I've ever had this sort of opportunity.
My name is Peter Tyedmers. I'm an ecological economist. My training includes undergraduate degrees in geological sciences and the law prior to undertaking my PhD studies at UBC in a department called resource management and environmental studies. Indeed, I know a couple of former colleagues from the west coast who have joined us by video conference.
For the last nine years I've been employed in the School for Resource and Environmental Studies at Dalhousie University. I was first appointed in 2001 as an assistant professor. In 2007 I became a tenured associate professor.
Within the domain of ecological economics, my research interests encompass an understanding of what I and others refer to as the life cycle energy and environmental impacts of food systems. We use something called life cycle assessment to try to understand the aggregate flows of material and energy inputs into how we produce things. My interests are in using LCA to understand the impacts of food systems, in particular fisheries- and aquaculture-related seafood systems, and the role technologies can play in moving us away from, or towards, more sustainable futures.
With colleagues and students, I've worked on a variety of research projects within fisheries and aquaculture, looking at U.S.-Canadian lobster fisheries, Antarctic krill fisheries, and global energy inputs to capture fisheries. I suspect, given the context of your current interest, that potentially you're most interested in the work we did in terms of our salmon life cycle assessment project. This was work that my students and I undertook with colleagues from the Swedish Institute for Food and Biotechnology in Gothenburg, Sweden, and from Ecotrust, based in Portland, Oregon.
It set out to try to characterize and understand the scale of material and energy flows and the resulting environmental impacts, at a global scale--meaning contributions to greenhouse gas emissions, utrifying emissions, etc.--associated with the major salmon farming regions of the world, those being Norway, Chile, Scotland, Alaska, and British Columbia. We do rank fourth in the world in production.
In the context of this project we also wanted to look at alternative ways in which salmon could be produced. One of my students undertook some work looking at what differences might flow from producing salmon organically, and another student undertook work looking at the potential implications of using alternative culture technologies, so we were looking at different environments in which we could grow salmonids. I'm assuming that this is the work that you're most interested in right now.
This work was led by my former student, Dr. Nathan Ayer. All of the work, including this, used what I refer to as life cycle assessment. The major question that we set out to answer was to better understand a potential shift from conventional net-pen culture to other forms of production. We and the people who joined us by video conference think we have a good understanding of the benefits these systems will provide in terms of reducing local ecological impacts, but to date, or before we did this work, we didn't really understand the scale of material and energy requirements to drive these systems and how these translate into broad-scale environmental concerns.
We undertook work to compare a very typical net-pen production in British Columbia as of the mid-2000s with a marine-based bag system that had been trialed in British Columbia, along with data from what we call a flow-through tank farm using salt water pumped out of the ocean into three tanks in which the salmon were cultured commercially for, I think, a total of three years, or two full grow-out cycles. We also used data from a very new farm. It's about four or five years old. It's a freshwater-based, recirculating culture technology system based in Nova Scotia, just outside Truro.
One thing I would mention is that while the other three systems we modelled were all culturing Atlantic salmon, the farm in Nova Scotia was culturing Arctic char. For our current purposes, I think the difference in species is less critical, but if people have an interest in it, I'd be pleased to discuss it.
We chose these systems because actual real data were available. We didn't set out to model artificial or theoretical systems, although those could be very interesting and insightful analyses to do. These were actual opportunities to exploit real data from real-world pilot studies or commercial operations to understand what it takes to grow salmon in different culture systems.
It was also a nice study from my perspective, because it allowed us to look at a spectrum of ways for culturing fish. If we think of a net pen as a fairly open system and a fully enclosed freshwater-based recirculating system as a system in which, if fish get out, all they do is flop around on the floor until they die, the study spans the whole range of potential technologies that are under consideration.
Before I briefly turn to some of our results, let me highlight two things.
Our work did not look at the local ecological benefits of these systems or the costs, nor did we have a chance to look at socio-economic dimensions.
The other important issue is that we did not attempt to quantify what might be possible with these technologies if they operated more efficiently, either because of economies of scale or because better technologies were applied through the use of better pumps or new ways of doing things with different feeds. We took the systems as they existed and as they were running. We found marked differences in the performance of the systems modelled.
I'll very briefly give a little background. When you do this type of work and look at a net-pen system, for example, you're concerned about the total amount of greenhouses gases that are emitted to produce a tonne of salmon. Typically 90% of greenhouse gases result from the provision of feed. As for what happens at the farm site or what happens when moving boats around, it doesn't really contribute very much at all. That's what we saw in the case of a net-pen culture system.
However, as you move towards a more intensive and more contained culture, you have to substitute eco-technologies, using pumps to move water around and adding oxygen, either in the form of bottled oxygen or oxygen generators. You need to use technologies to clean the water if you're going to have a recirculating system; otherwise, the environment isn't conducive to growing fish.
All of these technologies require power. You're substituting for the ecosystem services that are enjoyed by a net pen. Water flows through it, it's oxygenated, and it removes wastes. These things come at a price to local environments, but you're substituting them with technologies that are underpinned by electricity.
Let me give you some examples. The differences in the systems we modelled were fairly small between the net pen and the marine-based bag systems that were trialed in British Columbia, largely because the electricity required only had to move water a very short distance. It only had to lift water from outside the pen into the pen. Those systems turned out to be similar in terms of total energy input, total greenhouse gases, etc., but when you moved to land, using the existing technologies that were in Cedar, B.C., the energy input went up markedly.
To put this into context, I actually have notes here on the greenhouse gas emissions. Compared to the in-water net-pen system, the flow-through system had five times the total energy requirements and greenhouse gas emissions. When we looked at the recirculating system, I think the total energy and greenhouse gas emissions were approximately 10 times higher.
In part, however, the higher greenhouse gas emissions associated with the Nova Scotia culture system occurred because Nova Scotia electricity is about 80% coal-fired, whereas in British Columbia about 90% of electricity is provided through hydroelectricity, so the major source of these differences, when you look across the systems, is the much greater amount of energy required to pump water and to provide oxygen and filtration and other inputs to maintain high water quality. In the case of a land-based system, it is the fossil energy inputs needed in Nova Scotia to maintain the thermal regime of the culture environment. It gets cold in Nova Scotia, and in winter you have to heat the warehouses to keep the fish alive, or at least feeding at a rate that makes them economically successful.
Simply put, while isolating salmon from the aquatic environment may provide benefits in terms of reducing local ecological interactions, it also means that many of the ecosystem services, in terms of oxygen provision, waste elimination, and maintenance of a reasonable thermal regime, are diminished or lost and have to be substituted for through technologies.
This isn't to say that we shouldn't pursue larger-scale trials with land-based or closed-containment technologies. We just have to understand that in the pursuit of local-scale environmental and ecological improvements, we may be trading off contributions to global-scale concerns.