Thank you very much.
Good afternoon, and thanks to all the members who are present for the invitation to appear before the committee again. I think it's been a year and a half since I first appeared, and that was in person.
My name is Peter Tyedmers, and I am an associate professor in the School for Resource and Environmental Studies at Dalhousie University. My research focuses on understanding the resource and environmental sustainability of food systems, in particular fisheries and aquaculture systems. In this context, I'm particularly interested in the role that technologies play in moving us away from or toward sustainability.
To offer a little more detail, I've been attempting to measure the energy and related impacts of how we fish for and farm salmon for something like 15 years. Consequently, I broadly understand why I've been invited to appear as a witness for a second time, but I will admit to being a bit unclear as to the details of how I might best serve the committee. So my opening comments are going to be brief and generalized so that we can try to leave as much time for questions as possible.
Before I get into any substance, I'd like to make a quick observation that I've had a chance to look at some of the recent testimony that others invited to appear as witnesses have made, and reflecting on some of their testimony it occurred to me that I'd like to think that I'm not here to sell you on any specific ideas. While I know that some in industry, some in government, and some in the NGO community might see me, being an academic, as somewhat partisan, I'd like to believe that, if you'll excuse the English phrase, “I have no dog in this fight”. I'd like to think that I'm interested in just the understanding of how we do things and not so much in promoting one side or another.
All ways that we produce food and provide jobs have resource and environmental impacts. Seafood systems have many, if substantial, advantages over many other types of animal food production systems. The challenge from my perspective is how we understand what these resource and environmental impacts are and how we end up accepting the trade-offs that our choices entail.
If we think about closed containment aquaculture, we know that these systems can take many forms. We can think of them as lining up over a sort of continuum on a spectrum, in terms of the extent to which we substitute technologies that require material and energy inputs for ecological services that would otherwise be provided—to a certain extent, we could imagine—for free, but nothing is ultimately free, that sustain salmon in culture.
What are we talking about here? Well, depending on the type of culture system, in the closed containment system we're dealing with we have pumps that have to move water. That may involve moving water up hill or maybe moving water around a culture environment. We often need to bring supplemental oxygen in to keep animals alive. In some cases we use other technologies to strip waste products and either recover these waste products or at least submit them to the broader environment. That could be CO2, as a result of the respiration of these animals in culture. In a lot of closed containment environments we're dealing with very high densities of animal biomass, and if we don't remove the CO2, these animals will get sick and die very quickly.
In many of these contexts we also have the opportunity to strip excreted wastes. These might be solid wastes, wastes that are in the water. Depending on how we want to design these systems, we want to recover these and treat them, take them on land and do something with them.
Importantly, all of this is typically underpinned by energy inputs. It's very hard to escape the secondary requirements for additional energy inputs when we start to add new technologies and substitute them for ecosystem goods and services. The research I've done with some of my students and colleagues in the past suggests that these energy inputs can be very large, depending on the extent to which we're substituting technologies for ecosystem services.
Very briefly—and I'm sure that some of you may have had a chance to look at some of the work we've published in the past—when we've compared real-world data from net pen systems to that from in-water bag systems on land-based tank farms sited in British Columbia and that from land-based Arctic char farms on fresh water here in Nova Scotia, we have found that if we exclude the energy associated with providing feed, the electricity required on the farm sites for bag systems that required pumping was 1.5 kilowatt hours per live-weight tonne of salmon produced.
In contrast, a tank farm sited in Cedar, British Columbia, required over 13 kilowatt hours per kilogram of live salmon produced. The Arctic char farm here in Nova Scotia, given all of its challenges in actually producing healthy fish with relatively low inputs, was requiring over 22 kilowatt hours of electricity per live-weight tonne of fish.
If we step back and think about the broader life-cycle, total energy requirements of these systems—and for a 2009 paper in British Columbia, we modelled a net pen system and included all of the inputs associated with small provisioning and feed production and provisioning, and all the things that go on within the farm—it takes about 27 megajoules per kilogram of live-weight salmon produced. At the other extreme, when we look at the land-based Arctic char farm on fresh water, which has a full recirculation system, it took over eight and a half times the total amount of energy required to produce those animals, per kilogram of animal produced.
Somewhat similarly, although on a smaller scale, if we look at greenhouse gas emissions—this also includes the life-cycle greenhouse gas emissions associated with all of the feed provisioning, which is a critical aspect of understanding these systems—for net pens it was about two kilograms of CO2-equivalent greenhouse gases per kilogram of salmon produced in a net pen system. It was five times that level when we were looking at the Arctic char farm in Nova Scotia.
It's important to note that the work we've done in the past does not attempt to quantify local ecological benefits or costs of the systems we have characterized or attempt to quantify what might be possible if some of these systems worked more efficiently, through either better management or economies of scale, if those are possible, or the application of better, less resource-intensive technologies.
Essentially the work we have done in the past, and which I prefer to do, is to characterize systems based on their real-world performance. It's a critically important aspect. People engage in design and engineering to try to imagine what the next best technology is going to look like. We need this to happen. But if we assume that reality is going to mirror our theory and models perfectly, we are often in for a bit of a surprise.
The upshot is that while isolating salmon from the aquatic environment may provide benefits in terms of reducing local ecological interactions, that result is not guaranteed to occur in all closed containment technologies. It also means that many of the ecosystem services, whether we're talking about oxygen provisioning, waste assimilation, or maintenance of a reasonable temperature regime to keep animals alive, are diminished or lost when we substitute technologies underpinned by energy.
Let me be clear. I'm not saying that all closed containment technologies share in these challenges. If we think about the continuum of technologies that are available, at the extreme end we are basically rearing salmon in environments that are extremely far removed from what would naturally keep them alive. The only way we can do that is to provide a lot of energy inputs.
As I mentioned earlier, I've had a chance to review the testimony of some of your more recent witnesses that have appeared. While I would say I applaud their enthusiasm and optimism regarding the likely energy and associated greenhouse gas emissions for what they see as the proposed next generation of land-based closed containment technologies, I remain unconvinced regarding some of their projections. From my perspective, the numbers simply don't seem to make sense. They seem very optimistic. Again, ultimately, the proof has to be in the performance of these systems in the real world.
By comparing the energy and greenhouse gas emissions associated with different culture systems, as I think some of them have done, while excluding what is a central driver of energy costs to salmon culture and greenhouse gas emissions—by which I mean feed—they are greatly restricting what we can honestly say about the differences in these technologies at the back end.
So while it's important to make these comparisons, I think we have to be very guarded when we don't have real data on real performance. We're very limited in what we can say about the relative performance of two systems—net pens versus some sort of closed containment—if we choose to exclude what is in most cases one of the major drivers of impact, and that's feed.
I think that's still under 10 minutes, and I'd love to move to questions if that works for the committee.