10 Billion and Beyond: the Future of Aquaculture


A post of Karl Andree for Spotligth on aquaculture

A Historic Milestone

In the last few
years humanity passed two remarkable milestones. One was the population of the
planet surpassing 7 billion, which was widely noted in all forms of media, and
generally in a somewhat panicked and apocalyptic manner. And two, it was noted
much more quietly that in 2012, for the first time in modern history,
aquaculture production had overtaken cattle production. Given recent trends
this second milestone being passed was predictable, and for that reason it may
be that nobody gave this second event much notice.

But what are some of those
trends that brought this to pass, and what are the forcing factors that made
it, in a sense, predictable? Also, why should the average non-fish-eating
person care? First, let’s look at the forcing factors. Cattle production has
leveled off, even while consumption of beef in some countries has decreased
slightly. Many areas where cattle ranching is practiced intensively – North
America, South America and Australia – are close to capacity of their grazing
rangelands; this limits possible increases in production. There are various
reasons for reduced consumption as well, not least of which is the high
cholesterol content in red meat and its negative health impacts. This is made
clear to the public by a continuous supply of reports from health
professionals, as well as negative propaganda from competing industries like
poultry growers, regarding the health risks associated to red meat consumption.

Fishing has
always been a part of coastal communities, and historically it was a
sustainable practice. However modern commercial fishing has developed to a
stage where it is quite capable of outpacing the natural production of the
oceans. World wide there are populations of fish that are in a steep decline
with reductions of some species having exceeded 90%. Partly in response to
these alterations of the marine environment, aquaculture has become more
efficient and widespread in an effort to augment the decrease in wild-caught
fish. There has not been a competition between cattle and fish production, it
just turned out this way.

Fishing has always been a part of coastal communities, and historically it was a sustainable practice.


Upon announcement that the human population
had surpassed 7 billion there was a lot of negative press recalling various
statistics that have been promoted over the years that the planet cannot
sustain more than 7 billion people (or 5 billion, or 10 billion, depending on
who did the calculations); to attempt to feed more than this is beyond the
resources available on the planet. Like an apocalyptic video game – once there
are more people than food to feed them, the world comes to an end (“and the
zombies win!”). There are reasons to be excited and pleased about aquaculture
overtaking cattle production. Cold-blooded animals are more efficient at
converting the food they eat into the protein we eat. It takes 7 pounds of
grain for a cow to gain one pound of weight, whereas fish only consume two
pounds of feed to gain one pound of weight. Recalling world events of the
previous decade relating to global food supplies you may remember the talk of a
“post-petroleum economy” and the efforts to switch some grain production from
animal feed to biofuel feedstock and ethanol production. This coincided with a
couple bad weather years in the United States and Australia, two of the leading
grain-export countries, which in turn lead to grain shortages, price spikes and
food shortages.  Why are we digressing to
the topic of fuel? (It’s all connected.) Because reduced usage of grain
supplies to feed fish, instead of cattle, means the same quantity of protein
can be produced to feed humans and still have grain for converting to more
sustainable fuel alternatives (and by extension of this idea, it can also be
used to produce more protein to feed more people). This may require a change in
the mentality of those who refuse fish for dinner, but it will improve the
health of those who do make the change. 
And that change is coming.

Protein In, Protein Out

There are
controversies that the aquaculture industry must address before it is widely
seen as a solution to humanity’s future food supplies. Most notable among these
is the source of protein used in feeding fish. 
Top oceanic predators like tuna and swordfish currently are not grown in
captivity for aquaculture. It takes smaller fish like sardines to fatten them
for the market. Tuna captured and placed in net pens for fattening are removed
from the reproductive pool in the wild, and this further contributes to
depletion of wild fish stocks in much the same way as overfishing.
Additionally, there is a net loss in biological energy when feeding on top
predators as opposed to more sustainable alternatives like tilapia and carp
which can be grown on a vegetable protein diet, or sardines which are farther down
the food chain. To feed all of humanity with Siberian tigers is no more
sustainable for the same reason. Instead, most terrestrial meat sources for
humans are herbivores (cows) or omnivores (pigs). Carnivores like salmon and
tuna by contrast need to be fed fishmeal, which originates in the oceans.
However, progress has been made in improving the quality of fish diets with
reduced fishmeal content. Soybeans, canola, and other grains rich in protein
are being formulated as a replacement for protein originating from fish caught
in the wild. On some salmon farms in Chile the fishmeal content is now as low
as 15%. And this brings us back to the topic of improving the efficiency of the
use of our grain supplies. We can all become vegetarian, or we can find improved
food supply chains to convert vegetable protein into animal protein that are
not so wasteful as cattle production (ej. – aquaculture).

Don’t Fart

Another problem
that has attracted a lot of media attention is the methane that cattle produce
in their intestinal gases. The “carbon footprint” of both aquaculture and
agriculture are of serious concern these days. With considerable global
attention being given to climate change and the methane and CO2 gases that are
produced by human activities (cattle production among them) seen as the primary
driver behind climate change, it gives cattle production and by extension beef
consumption, a bad reputation beyond just high cholesterol. These are part of
the reasons that beef consumption has seen a slight decline in western
countries even as rising Asian economies are increasing their consumption.

There have been several scientific studies published in regards to cattle and
pig flatulence and attempts are underway to curb their gas production through
modified diets and selective breeding. Fish by contrast must regulate their
floatation, or buoyancy, to swim properly and no excess gas production in their
metabolism can be tolerated.

Fish Don’t Fart

They are not ruminants like cows. Whereas cattle
on the other hand, have multiple stomachs and there is considerable
fermentation that takes place inside their digestive tracts (think of the CO2
gases produced during fermentation of beer for example). Shellfish, such as
oysters, are even better for the environment in terms of a carbon footprint and
climate changing gases. The oceans have absorbed from the atmosphere some of
the CO2 produced in excess and this is altering the chemistry of the oceanic
waters. However, the carbonate of oyster shells is a very stable “carbon sink”.
It removes CO2 from the oceanic waters, and this can help to balance the
adverse aspects of the “carbon footprint” of aquaculture activities somewhat.
Further, oysters and other filter-feeding shellfish like mussels and clams do
not compete with protein sources used by humans, or require other significant
energy inputs (read sources of CO2 output) for their growth.

The aquaculture revolution is officially now here upon us

The aquaculture
revolution is officially now here upon us. It is a quiet revolution with great
promise for providing sustainable protein sources for the burgeoning human
population. So the next time you choose grilled sardines or marinated oysters
instead of that grilled beef sirloin, you can remind yourself and feel good
about how you are improving the air quality, the marine environment, and the sustainability
of the food supply, as well as your personal health benefits.

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