Agriculture worldwide is rapidly sucking up freshwater from underground aquifers formed thousands of years ago.
Advanced agriculture, which relies on irrigation, has allowed our planet to flourish. We have the technology to feed every single person on this planet. The only reason this isn’t happening is purely because of political struggles.
But advanced agriculture has come with a price. New research shows we are using up freshwater at a frighteningly unsustainable rate in some parts of the world.
There is still a lot of groundwater which is not under enormous pressure, but that’s not an excuse to ignore what we are currently doing in the areas experiencing stress. Yes, we could suck these aquifers dry and then import water from other countries. But this is not acceptable if we want to have control over our own food supplies in Canada and the United States, or whatever part of the world we are in. It would also drive up food prices immensely, and is hardly a responsible use of one of our planet’s most precious resources: fresh water.
Besides, these aquifers won’t refill for thousands of years and draining them would have dramatic environmental impacts.
The problem with drawing too much water from an aquifer, which has been stored in these geologic formations for thousands of years, is that it can’t easily be restored once pumped dry. That’s the crisis facing farmers who rely on the Ogallala Aquifer, which once contained enough water to cover the entire continental U.S. roughly half-a-meter deep. Once pumped dry, the Ogallala would take at least 6,000 years to refill.
Another complication of pumping too much water from an aquifer is that creeks will run dry and surface waters can literally be sucked back underneath the surface. That’s not good for wildlife. Yet the world needs more water to meet the demand of a growing population for food.
This brings us to closed-containment salmon farming. Pardon us while we climb up on our soapbox here.
Critics of salmon farming often say we should just grow fish on land, as if it was the most natural thing in the world to do. It’s about as natural as farming chickens underwater. Yes, you could do it, but why?
We do not believe there is any reason to farm fish on land when we have a perfectly good ocean. Responsible salmon farms have very small environmental impacts, so there’s no need to force them on land to manage what is really just a perceived risk.
We do acknowledge that salmon farming has an impact. Yes, fish poop. Yes, fish get sick. But while these are serious problems that salmon farmers are always trying to mitigate, thanks to huge advances in farming practices and technology over the last 20 years, they present a very low risk to the environment and a very low risk to wild fish.
We believe farming salmon on land would just be environmental problem-shifting, trading problems in the ocean for problems on land, and we believe the problems on land would actually be worse for the environment. For one thing, farming salmon on land would require a lot of land and as Mark Twain said, “they’re not making it anymore.” Is a field of tanks really the best use of our increasingly limited flat land? Especially land which needs to be close to a three-phase power source, fresh water and transportation to make a land-based salmon farm financially plausible?
1,150 Gigawatts? Great Scott!
The electricity costs will be high. Proponents of land-based salmon farms are usually very elusive about electricity costs, but Andrew Wright, who is associated with the “Save Our Salmon” group, suggested in his “Technologies for Viable Salmon Aquaculture” report two years ago that if all salmon farms in B.C. were moved on to land, they would use as much energy per year as “two or three pulp mills.”
That’s a lot. He pegs the number at $81 million per year spend on electricity alone and estimates that an entirely land-based salmon farming industry would use 1,150 gigawatt-hours of electricity per year, as much as a city. That would make a land-based salmon farming industry BC Hydro’s single biggest customer. The capacity does not exist to provide this much more electricity in B.C.
Are the people who clamour for salmon farms to be moved on land willing to see BC Hydro use tax dollars to build the new run-of-river or hydroelectric dams on our precious freshwater supplies that would be needed to power an entirely land-based aquaculture industry? No, they would not, if the salmon farm-hating “Common Sense Canadian” is any indication. Long-time salmon farm opponent (and closed-containment advocate) Rafe Mair recently interviewed an economist who suggested that “ if there are to be things built to serve industrial customers, they should be built site-specific and they should be for customers at full cost to produce. No subsidies from the public.”
That sounds about right for Mair and his acolyte, Damien Gillis, who run the website and who are strongly associated with the anti-salmon farming crowd.
The same people who want salmon farmers to move on land would force them to build an entire new electrical infrastructure to support themselves, too. It’s safe to say this will never happen. Salmon farms will simply disappear in B.C. and other countries willing to spend public money to grow an aquaculture industry, such as the United States, will do it instead.
Freshwater costs – are they worth it?
The afore-mentioned Wright is currently involved with a project near Port McNeill. The ‘Namgis First Nation has received roughly $7 million to build a land-based recirculating aquaculture system capable of growing 470 metric tonnes per year of market-size Atlantic salmon.
In comparison, a conventional ocean farm costs about $5 million and is capable of growing 3,000 metric tonnes per year of market-size salmon.
The ‘Namgis project fact sheet as well as a presentation by Tides Canada, one of the project’s major funders, says the project will recycle water at about the same rate as the land-based recirculating aquaculture systems the salmon farm companies use to grow smolts, which is around 99 per cent efficient.
Let’s do some really rough math. If five 500 cubic metre tanks can grow 470 metric tonnes of salmon, theoretically, it would take 74,468 cubic metres of water to grow the 70,000 tonnes of farmed salmon produced annually in B.C. At 99 per cent recirculation efficiency, that would mean 745 cubic metres of freshwater would be used every day to reinvigorate in the recirculation systems. That’s 745,000 litres of water per day.
And we haven’t even counted the water needed for broodstock, eggs, fry and smolts.
With our world’s freshwater supply becoming more and more valuable, why would we use it to grow fish on land when we have a perfectly good ocean?
ADDENDUM 2012-10-18: It appears our rough math was inaccurate. Commenter Jim has posted a more detailed analysis of how much freshwater it would take to move B.C. salmon farms on land, and the figure he came up with is that it would require 107 million litres of freshwater per day! Take a look at his figures on our discussion page.
The obligatory car analogy
Every good Internet blog post has to include a car analogy. Here’s ours.
Current net-pen technology could be compared to the run-of-the-mill car on todays road.
As the years have gone on they have transformed from lumbering, fuel guzzling behemoths with no seatbelts into fuel efficient, safe and versatile units. Much in the same way, net-pens have evolved while incorporating natural processes to provide a safe and effective way to produce salmon.
Of course you will always have accidents – drunk drivers, operator error, and bad weather will plague highways the same as plankton blooms, low dissolved oxygen and pathogens will impact net-pens.
Transitioning all net-pens to land-based facilities would serve to solve some of these issues, but would come at quite a cost in efficiency, animal welfare and other environmental impacts. It would be like guarding yourself against drunk drivers, operator error and bad weather by transporting your family in an automated, armoured track vehicle.
Of course you would be safe(r), but you would also sacrifice the fuel efficiency, comfort and cost effective nature of todays cars.
We all live with real dangers every day, but as a species we have learned to adapt to them and find a balance between fear and risk-management. Society will always have those who do not feel that any risk is acceptable, and who will try to convince others that their views are justified.
Highways are not filled with uber-safe tanks because the trade-offs are unacceptable to the vast majority of people, the same way as uber-safe tanks are not used for raising salmon.
Farming salmon in the ocean is the best place for them. The environmental risks are low, and although farmers would love to move their fish on land where they can control every aspect of their growth, go home to their kids at night and not shiver through freezing cold winters out on the ocean, it’s just not practical. Maybe someday, but not now, and not likely for a long time.
“There are lies, damned lies and statistics.”
Mathematicians and statisticians know that with a little bit of dishonesty, you can make numbers say almost anything you want.
The whole debate over sea lice and salmon farming has been a numbers issue. Aquaculture opponents say their mathematical modelling studies, which amplify weak correlations from their observational data is enough proof to claim that sea lice from salmon farms kills wild salmon.
Aquaculture supporters say the numbers do not support that conclusion, and point out their own studies, which tend to be based strictly on observational data than mathematical modelling, show no meaningful correlations.
And as we all know, correlation does not equal causation, but the lack of correlation doesn’t mean there’s not something going on.
Clear as mud, right?
Perhaps this recent article in Scientific American can help explain. Do we eat more food when we are given bigger plates, or smaller plates? Mathematician John Allen Paulos shows how with just slight manipulation of the numbers, you can argue both.
A recent study by researchers at the University of Utah suggested that the amount of food diners in a restaurant consumed was influenced by fork size. I haven’t seen details of the study, but it does remind me that people can draw diametrically opposite conclusions from the same raw data by altering definitions ever so slightly.
If only such contradictory results were contrived and isolated phenomena, but they’re not. When dealing with weakly correlated quantities, we often can come up with spurious trends and associations by artfully defining the size of the categories we use. This has been done recently in studies of violent crime to show that certain categories of crime were changing in the desired direction, and I intend to illustrate the point here with a similar story.
Using the fork study for inspiration only, let’s see how small variations in definitions can make all the difference. Imagine 10 diners at a buffet and consider the possible influence of plate size on how much they consume. Three diners were provided with plates that were deemed small, say, less than 8 inches in diameter, and they consumed 9, 11 and 10 ounces of food, for an average of 10 ounces. Now further assume that four diners were provided with medium-size plates, say, between 8 and 11 inches in diameter, and they consumed 18, 7, 15 and 4 ounces of food, for an average of 11 ounces.
Finally, we’ll assume that the remaining three diners were provided with plates deemed large, say, larger than 11 inches in diameter, and they consumed 13, 11 and 12 ounces, for an average of 12 ounces.
Spot the trend? As the plate sizes increased from small to medium to large, the average amount consumed increased from 10 to 11 to 12 ounces. Aha, a nice result!
But wait. What if the medium-size plates were very slightly redefined to be between 8.2 and 10.8 inches, and the small and large plates were redefined accordingly? And what if this redefinition resulted in the misclassification of two diners? The diner who ate 18 ounces of food was actually provided with a small plate (say, 8.1 inches in diameter), and the diner who ate only 4 ounces was actually provided with a large plate (say, 10.9 inches in diameter).
Let’s do the numbers once again under this assumption. Four (rather than three) diners were provided with small plates, and they consumed 9, 11, 10 and 18 ounces of food, for an average of 12 ounces. Two (rather than four) diners were provided with medium-size plates, and they consumed 7 and 15 ounces of food, for an average of 11 ounces. Four (rather than two) were provided with large plates, and they consumed 4, 13, 11 and 12 ounces of food, for an average of 10 ounces.
Spot the trend? As the plate sizes increased from small to medium to large, the average amount consumed decreased from 12 to 11 to 10 ounces. Aha, a nice result!
Moreover, small samples are not the problem here. A large number of data points make this sleight of hand even easier because it provides more opportunity to fiddle with the categories. Anyone for sunspot intensity or Super Bowl outcomes?
The take-home point here is that numbers can be manipulated. Be careful.
When making decisions about things like what size plate to take at the buffet or whether or not salmon farms are the root of all evil, a level head, good observational data and consistent, transparent mathematics are best.
And above all, be skeptical. Look for good science, and use your common sense.