SUCH a
great idea! This is how it would work; we would breed tigers in captivity,
thousands of them. Then we would go into the jungle with big drag nets and
catch every animal we could find as feed for the tigers. Some of these animals,
big and small, would be thrown into the tigers while still reasonably fresh.
Others could be ground up and cooked with other ingredients to be made into
tiger-feed pellets. Actually, we would be better off grinding them up in this
way because the fresh animal feed could introduce bacteria that increased the
mortality rate at our tiger farm.
Of course,
we would quickly run out of animals in our local jungle and would have to buy
quite a lot from professional hunters who dragged nets through other jungles
and forests. Also, tigers being what they are, we would have to feed anything
from 5 to 15+ kilograms of squirrels, monkeys, tapirs, orangutans, sun bears,
flying foxes etc. for every one kilogram of tiger meat we produced, but that
doesn’t really matter because tiger meat is worth so much more in the
marketplace than those other animals, many of which are ‘trash’ animals anyway.
Pity about
the jungle habitat that we would destroy as trees and other foliage is ripped
from the ground by our nets. And of course there are the folk who have
sustainably relied for millennia on the jungle and the animals we are now
throwing into our pens teeming with tigers, but that’s progress isn’t it? Time
they moved on and got a job somewhere else anyway I suppose.
Sounds like
a smashing idea doesn’t it! We would make a killing, if you will excuse the puns.
Well, for a while anyway. Hopefully, long enough to get rich and move on.
Imagine, if
you will, the hue and cry that would be heard around the world were a company
to declare triumphally that they had established a business that bred and
reared tigers in captivity for food. Imagine further how the clamour would be
exacerbated if the company went into the wild jungle as I suggest above capturing
animals and feeding them to the tigers.
Would any
sane person argue that such a business model is a solution to future food insecurity?
And yet, this is more or less what we are doing in the oceans.
Many people
mistakenly believe that aquaculture is the equivalent of farming ruminants.
That fish farming is like letting cows, sheep, goats etc. graze on grass to
give us protein through their meat. However, in many respects this is
incorrect, especially for those fish that are fed other fish.
Many of the
marine fish bred and reared in aquaculture farms are upper trophic-level
predators. Tuna is a carnivore hunter, like the tiger, and in the case of
Pacific Bluefin Tuna, is becoming almost as rare.[1] But the Mediterranean Sea is
littered with ‘tuna farms’ where tuna are fattened on wild-caught fish before
being harvested for sashimi and sushi. FAO reports that, “Feed
conversion ratios (FCR) are generally high around 15-20:1 for large specimens
and 10-15:1 for smaller fish. Bluefin tuna maintain an unusually high body
temperature and their constant movement implies a high energy demand. As a
result only a small fraction (5 percent) of the total energy input is used for
body growth.[2]
Now, I must
admit that my description of tiger farming suffers from some limitations as an
analogy for marine finfish aquaculture. For a start, fish species like
groupers, barramundi (Asian sea bass) and salmon are not endangered or even
threatened. But aquaculture operations using these fish do rely on large
quantities of wild-caught fish, which are either fed directly to the farmed
fish or turned into pellets containing fishmeal and fish oil.
Of course,
an important driver for an increase in aquaculture production is the inability
of wild-caught fish to meet human demand for fish protein. According to Steve
Hall, Director General of World Fish Centre, “4.5 billion people get at least
15 percent of their average per capita intake of animal protein from fish”.[3]
In 2012,
around 91.4 million metric tons of fish were caught globally from the wild; of
this, approximately 11.6 million metric tons were caught from inland waters and
79.7 million metric tons were caught in marine fishing areas.[4] The volume of capture fish
production has remained roughly the same since at least 2006.
Also in
2012, about 66.6 million metric tons of fish were produced through aquaculture.[5] Of this total,
approximately 10 million metric tons were marine fish and diadromous fish that
are fed fishmeal and fish oil-based aquafeed.[6] A substantial portion of
freshwater aquaculture production also relies on fishmeal, e.g. tilapia.
As with the
forests and jungles that would quickly empty of animals were we to drag nets
through them to catch feed for tiger farms, so we are emptying the oceans in
part to feed fish in aquaculture farms that often produce less fish than they
use as feed. In 2012, a total of 16.3 million metric tons of fish were caught
to produce fishmeal and fish oil.[7] The International
Fishmeal and Fish Oil Organisation estimate that in 2010, the aquaculture
industry utilized 73% of total fishmeal production. In the case of fish oil,
the estimates are that 71% is used as aquafeed and 26% for human consumption.[8]
Admittedly, not all of this production comes from whole fish; in 2012, about
35% of world fishmeal production was obtained from fish residues (by-products
and waste rather than whole fish) but this still leaves around 10.5 million
metric tons made from whole fish.[9]
Salmon farming in
particular has a high demand for wild forage fish. One of the main attractions
of salmon at market is the beneficial effects on health of salmon flesh
containing omega-3 fatty acids. However, fish do not actually produce omega-3
fatty acids; rather, they accumulate them from either consuming microalgae that
produce these fatty acids, e.g. as do herring and sardines, or, as is the case
with fatty predatory fish like salmon, by eating prey fish that have
accumulated omega-3 fatty acids from microalgae. To satisfy the requirement for
fish that are rich in omega-3 fatty acid, more than 50 percent of the world
fish oil production is fed to farmed salmon.
The by-catch
of fishmeal and other fisheries is difficult to know but has been estimated
globally to total about 27 million metric tons.[10] In January 2015, The New York Times reported Douglas J. McCauley, an ecologist at the
University of California, Santa Barbara, as saying that “We may be sitting on a
precipice of a major extinction event”.[11]
In January 2015, researchers at the University of Sheffield UK released a
report finding that “up to a quarter of the planet’s well-known marine species,
from the Mediterranean monk seal to the Pondicherry shark, are in danger of
being wiped out. This overturns the conventional scientific wisdom that marine
species are far safer than others, by establishing that the risk is equally
high. In each case, between 20 and 25 per cent of species are threatened with
extinction”.[12]
The Marine
Fisheries Service of the US National Oceanic and Atmospheric Administration
(NOAA) reports that, “Many commercial fish stocks reveal a pattern of declining
populations. Recent trends indicate that about one-third of the resources on
which fishers depend are overfished in the United States and worldwide...
Without major changes in fishery management, FAO estimates that global landings
will not be able to exceed current levels despite increased demand from growing
populations, and could be reduced by as much as 25 percent”.[13]
The demand for marine predator fish
is not going to disappear and be replaced by consumption only of herbivore
fish. Therefore, if the pressure on wild caught fish is to be reduced and
sufficient feed is to be available to meet the demand of future aquaculture, we
must break the nexus between aquaculture output and the capture of wild fish as
feed.
In recent
decades, there has been extensive research on ingredients to replace fishmeal,
but this research has tended to focus on sources of plant protein such as corn
and soya. These crops are now used in some commercial aquaculture feeds.
However, some species of fish, such as grouper (e.g. Epinephelus
spp., Cromileptesaltivelis and Plectropomus spp.), and fish at certain life stages
require high levels of protein and have low metabolic limits for carbohydrate.[14] In these instances, the
incorporation of mainstream crops into fish feed has had less than optimal
results.[15]
In addition, many countries do not grow these mainstream crops and are
therefore left in the undesirable position of having to import alternatives to
fishmeal, which can be cost prohibitive.
I am
currently Research Director of the ‘FishPLUS’ programme at Crops for the
Future. In order to help address this problem, our researchers are working with
partners around the world to identify fish feed ingredients from underutilised
plant species such as Moringa (Moringa
oleifera) and Bambara Groundnut (Vigna subterranea), and to explore how insects, such as Black
Soldier Fly (Hermetia illucens) and
Rhinoceros Beetle (Dynastinae), fed on plant species that can be grown
locally might be incorporated into fish feed formulations. The research is at
an early stage but holds considerable promise for the future of marine
aquaculture as a sustainable source of protein. I am aware that similar work is
being done at other institutions around the world, including University of
Stirling UK, and universities and private companies in USA. For the sake of the
oceans and the future well-being of people around the world, these efforts must
succeed.
We can
avoid the folly of eating tigers but we are already eating their marine
equivalents. We critically need to find an alternative to dragging nets through
the oceans to produce their feed.
Published in The Malaysian Insider, 19 July 2015
[1] “Over the last four decades, the Atlantic Bluefin
tuna has declined by at least 51% and is now listed as “Endangered”; while the
Southern Bluefin tuna adult fish has experienced an 85% decline, resulting in
its “Critically Endangered” status. The Pacific Bluefin tuna has also been
listed as “Vulnerable” species.” WWF, See:
http://www.wwf.org.hk/en/whatwedo/footprint/seafood/sci/campaigns/bluefinsaver/threats/
[2] Ottolenghi, F. 2008. Capture-based
aquaculture of Bluefin tuna. In A. Lovatelli and P.F. Holthus (eds).
Capture-based aquaculture. Global overview. FAO Fisheries Technical Paper.
No. 508. Rome, FAO. pp. 169–182.
[3]
See http://www.seafoodsource.com/news/aquaculture/28195-worldfish-discusses-climate-change-impact-on-aquaculture
[4]
World Capture Production, see ftp://ftp.fao.org/FI/STAT/summary/a1a.pdf
[5] World fisheries production, by capture and
aquaculture, by country (2012). See, ftp://ftp.fao.org/FI/STAT/summary/a-0a.pdf
[6] Seafish, The Global Picture – World Aquaculture, See http://www.seafish.org/media/publications/SeafishSummary_WorldAquaculture_Globalpicture_201208.pdf
[7] FAO: The State of World Fisheries and
Aquaculture 2014 (244 pages) http://www.fao.org/3/a-i3720e.pdf
[8] Seafish, ‘The Global Picture –
Fishmeal Production’ June 2014, see: http://www.seafish.org/media/publications/seafshsummary_fishmealglobalpicture_201406.pdf
[9] Loc. cit.
[10]
NRC By-catch Database reported at FAO, http://www.fao.org/docrep/003/t4890e/t4890e03.htm
[11]
Zimmer, C., ‘Ocean Life Faces Mass
Extinction, Broad Study Says’, The New York Times, 15 January 2015. See, http://www.nytimes.com/2015/01/16/science/earth/study-raises-alarm-for-health-of-ocean-life.html
[12]
As reported in ‘A quarter of the world’s marine species in danger
of extinction’, The Independent, 30
January 2015, see: http://www.independent.co.uk/environment/a-quarter-of-the-worlds-marine-species-in-danger-of-extinction-10014624.html
[13] Hourigan, T.F., ‘Conserving Ocean Biodiversity: Trends and
Challenges’,
Trends and Future Challenges for
U.S. National Ocean and Coastal Policy. See: http://oceanservice.noaa.gov/websites/retiredsites/natdia_pdf/7hourigan.pdf
[14]
Tuan, L.A.; Williams, K.C. Optimum dietary protein and lipid specifications for
juvenile malabar grouper (Epinephelus malabaricus). Aquaculture,
v.267, p.129‑138, 2007.
[15] J. Wood, Project Funding Submission,
Crops for the Future, 2014, unpublished.
