October 3, 2000-9
Copyright © 2001 Earth Policy Institute
Fish Farming May Soon Overtake Cattle
Ranching As a Food Source
Lester R. Brown
Aquacultural output, growing at 11 percent a
year over the past decade, is the fastest growing sector of the
world food economy. Climbing from 13 million tons of fish produced
in 1990 to 31 million tons in 1998, fish farming is poised to overtake
cattle ranching as a food source by the end of this decade. (See
table below.)
This record aquacultural growth is signaling a
basic shift in our diet. Over the last century, the world relied
heavily on two natural systems oceanic fisheries and rangelands
to satisfy a growing demand for animal protein, but that
era is ending as both systems are reaching their productive limits.
Between 1950 and 1990, beef production, four fifths of it from rangelands,
nearly tripled, climbing from 19 million to 53 million tons before
plateauing. Meanwhile, the oceanic fish catch grew from 19 million
to 86 million tons, more than quadrupling, before leveling off.
Since 1990, there has been little growth in either beef production
or the oceanic fish catch.
Additional production of beef or seafood now depends
on placing more cattle in feedlots or more fish in ponds. At this
point, the efficiency with which cattle and fish convert grain into
protein begins to reshape production trends and thus our diets.
Cattle require some 7 kilograms of grain to add 1 kilogram of live
weight, whereas fish can add a kilogram of live weight with less
than 2 kilograms of grain. Water scarcity is also a matter of concern
since it takes 1,000 tons of water to produce 1 ton of grain. But
the fish farming advantage in the efficiency of grain conversion
translates into a comparable advantage in water efficiency as well,
even when the relatively small amount of water for fish ponds is
included. In a world of land and water scarcity, the advantage of
fish ponds over feedlots in producing low-cost animal protein is
clear.
In contrast to meat production, which is concentrated
in industrial countries, some 85 percent of fish farming is in developing
countries. China, where fish farming began more than 3,000 years
ago, accounted for 21 million tons of the 31 million tons of world
aquacultural output in 1998. India is a distant second with 2 million
tons. Other developing countries with thriving aquacultural sectors
include Bangladesh, Indonesia, and Thailand.
Among industrial countries, Japan, the United States,
and Norway are the leaders. Japans output of 800,000 tons
consists of high-value species, such as scallops, oysters, and yellowtail.
The U.S. output of 450,000 tons is mostly catfish. Norways
400,000 tons is mostly salmon.
With overfishing now commonplace, developing countries
are turning to fish farming to satisfy their growing appetite for
seafood largely because the oceanic option is not available to them
as it was earlier to industrial countries. For example, as population
pressure on the land intensified in Japan over time, it turned to
the oceans for its animal protein, using scarce land for rice. Today
Japans 125 million people consume some 10 million tons of
seafood each year. If Chinas 1.25 billion were to eat seafood
at the same rate, they would need 100 million tons-the global fish
catch.
Although at least 220 species of fin fish, shellfish,
and crustaceans are farmed commercially, a dozen or so dominate
world output. Among the fin fish, five species of carp all
widely grown in China lead the way with a combined output
of some 11 million tons in 1998, more than a third of world aquacultural
output. Among shellfish, the Pacific cupped oyster, at 3.4 million
tons (including shell), dominates, followed by the Yesso scallop
and the blue mussel.
In China, fish are produced primarily in ponds,
lakes, reservoirs, and rice paddies. Some 5 million hectares of
land are devoted exclusively to fish farming, much of it in carp
polyculture. In addition, 1.7 million hectares of rice land is used
to produce rice and fish together.
Over time, China has evolved a fish polyculture
using four types of carp that feed at different levels of the food
chain. Silver carp and bighead carp are filter feeders, feeding
on phytoplankton and zooplankton, respectively. The grass carp,
as its name implies, feeds largely on vegetation, while the common
carp is a bottom feeder, living on detritus that settles to the
bottom. Most of Chinas aquaculture is integrated with agriculture,
enabling farmers to use agricultural wastes, such as pig manure,
to fertilize ponds, thus stimulating the growth of plankton. Fish
polyculture, which typically boosts the fish yield per hectare over
that of monocultures by at least half, also dominates fish farming
in India.
As land and water become scarce, Chinas fish
farmers are intensifying production by feeding more grain concentrates
to raise pond productivity. Between 1990 and 1996, Chinas
farmers raised the annual pond yield per hectare from 2.4 tons of
fish to 4.1 tons.
In the United States, catfish, which require only
1.6 kilograms of feed to gain 1 kilogram of live weight is the leading
aquacultural product. With U.S. catfish production last year at
roughly 600 million pounds (270,000 tons), or more than 2 pounds
for each American, U.S. consumption of catfish exceeded that of
lamb and mutton. U.S. catfish production is concentrated in four
states: Mississippi, Louisiana, Alabama, and Arkansas. Mississippi,
with some 174 square miles (45,000 hectares) of catfish ponds and
easily 60 percent of U.S. output, is the catfish capital of the
world.
Among the aquatic species that are widely farmed,
two especially wreak extensive environmental havoc salmon,
with production of 700,000 tons per year, and shrimp at 1,100,000
tons per year. Salmon are grown mostly in industrial countries,
principally in Norway, for consumption in those countries. Shrimp,
by contrast, are grown largely in developing countries, importantly
Thailand, Ecuador, and Indonesia, for export to more affluent societies.
Salmon, a carnivorous fish, are fed a diet consisting
primarily of fishmeal that is typically made from anchovies, herring,
or the remnants of fish processing. In stark contrast to the production
of herbivorous species, such as carp and catfish, which lighten
the pressure on oceanic fisheries, salmon production actually intensifies
pressure because it requires up to 5 tons of landed fish for each
ton of salmon produced.
Another concern is that if farmed salmon, which
are bred for fast growth and not for survival in the wild, escape
because of damage to the pens by storms or attacks by predators,
such as harbor seals, they can breed with wild salmon, weakening
the latters capacity to survive. Fish grown in offshore cages
or pens, as salmon frequently are, also concentrate large quantities
of waste, which itself presents a management problem. For example,
the waste produced by farmed salmon in Norway is roughly equal to
the sewage produced by Norways 4 million people.
Shrimp are often produced by clearing coastal mangrove
forests which protect coastlines and serve as nurseries for local
fish. Mangrove destruction can cause a decline of local fisheries
that will actually exceed the gains from shrimp production, leading
to a net protein loss. In addition, because shrimp rations are also
high in fishmeal, shrimp, like salmon, put additional pressure on
oceanic fisheries.
A world that is reaching the limits with both oceanic
fisheries and rangelands while adding 80 million people each year
needs efficient new sources of animal protein. Herbivorous species
of fish, such as carp grown in polycultures, carp grown in combination
with rice, or catfish grown in ponds, offer a highly efficient way
of expanding animal protein supplies in a protein-hungry world.
Fish farming is not a solution to the world food problem, but as
China has demonstrated, it does offer a potential source of low-cost
animal protein for lower income populations. The forces that have
made aquaculture the worlds fastest growing source of animal
protein over the last decade are likely to make
it the fastest growing source during this decade as well.
World
Aquacultural and Beef Production, 19501998 |
|
Aquacultural
Production |
Beef
Production |
Year |
Total
(million
tons) |
Per
Capita
(kilograms) |
Total
(million
tons) |
Per
Capita
(kilograms) |
World
Population
(billion) |
1950 |
1.5 |
0.6 |
19.34 |
7.57 |
2.556 |
1951 |
1.7 |
0.6 |
19.80 |
7.64 |
2.594 |
1952 |
1.7 |
0.7 |
20.49 |
7.77 |
2.636 |
1953 |
1.8 |
0.7 |
22.40 |
8.35 |
2.681 |
1954 |
1.9 |
0.7 |
23.42 |
8.58 |
2.729 |
1955 |
2.1 |
0.7 |
24.26 |
8.73 |
2.780 |
1956 |
2.1 |
0.8 |
25.76 |
9.09 |
2.833 |
1957 |
2.3 |
0.8 |
26.07 |
9.03 |
2.889 |
1958 |
2.5 |
0.8 |
26.14 |
8.87 |
2.945 |
1959 |
2.8 |
0.9 |
26.37 |
8.80 |
2.997 |
1960 |
3.0 |
1.0 |
25.60 |
8.42 |
3.039 |
1961 |
3.2 |
1.0 |
27.68 |
8.99 |
3.080 |
1962 |
3.3 |
1.0 |
29.20 |
9.31 |
3.136 |
1963 |
3.4 |
1.1 |
30.86 |
9.63 |
3.205 |
1964 |
3.6 |
1.1 |
31.28 |
9.55 |
3.276 |
1965 |
3.7 |
1.1 |
31.86 |
9.52 |
3.345 |
1966 |
3.9 |
1.1 |
33.55 |
9.82 |
3.416 |
1967 |
4.0 |
1.2 |
35.27 |
10.12 |
3.485 |
1968 |
3.9 |
1.1 |
36.97 |
10.39 |
3.557 |
1969 |
3.7 |
1.0 |
37.93 |
10.44 |
3.631 |
1970 |
3.6 |
1.0 |
38.35 |
10.35 |
3.707 |
1971 |
3.8 |
1.0 |
38.04 |
10.05 |
3.784 |
1972 |
3.8 |
1.0 |
38.53 |
9.98 |
3.861 |
1973 |
3.9 |
1.0 |
38.84 |
9.87 |
3.937 |
1974 |
4.0 |
1.0 |
41.84 |
10.43 |
4.013 |
1975 |
4.1 |
1.0 |
43.72 |
10.70 |
4.086 |
1976 |
4.8 |
1.1 |
46.05 |
11.07 |
4.158 |
1977 |
4.8 |
1.1 |
46.38 |
10.96 |
4.231 |
1978 |
4.8 |
1.1 |
46.88 |
10.90 |
4.303 |
1979 |
5.0 |
1.1 |
45.73 |
10.45 |
4.378 |
1980 |
5.2 |
1.2 |
45.49 |
10.21 |
4.454 |
1981 |
5.4 |
1.2 |
45.86 |
10.12 |
4.530 |
1982 |
5.6 |
1.2 |
45.81 |
9.94 |
4.610 |
1983 |
5.9 |
1.3 |
47.10 |
10.04 |
4.690 |
1984 |
6.7 |
1.4 |
48.41 |
10.15 |
4.770 |
1985 |
7.7 |
1.6 |
49.20 |
10.14 |
4.851 |
1986 |
8.8 |
1.8 |
50.92 |
10.32 |
4.933 |
1987 |
10.1 |
2.0 |
51.00 |
10.16 |
5.018 |
1988 |
11.7 |
2.3 |
51.40 |
10.07 |
5.105 |
1989 |
12.3 |
2.4 |
51.71 |
9.96 |
5.190 |
1990 |
13.1 |
2.5 |
53.37 |
10.11 |
5.277 |
1991 |
13.7 |
2.6 |
53.82 |
10.04 |
5.359 |
1992 |
15.4 |
2.8 |
52.94 |
9.73 |
5.442 |
1993 |
17.8 |
3.2 |
52.38 |
9.48 |
5.523 |
1994 |
20.8 |
3.7 |
53.10 |
9.48 |
5.603 |
1995 |
24.4 |
4.3 |
53.97 |
9.50 |
5.682 |
1996 |
26.8 |
4.7 |
54.60 |
9.48 |
5.761 |
1997 |
28.8 |
4.9 |
55.14 |
9.44 |
5.840 |
1998 |
30.7 |
5.2 |
55.26 |
9.34 |
5.919 |
1999 |
|
|
55.42 |
9.24 |
5.996 |
2000 |
|
|
|
|
6.158 |
Source:
U.N. Food and Agriculture Organization (FAO), Yearbook
of Fishery Statistics: Capture Production (various
years); FAO, Aquaculture Production (various years); FAO,
Fisheries Web site.
|
(107k, approx. 26 sec at 33.6 speed)
Copyright
© 2000 Earth Policy Institute
|
|
Email this Alert to a friend
Printer friendly format
FOR ADDITIONAL INFORMATION
From Worldwatch Institute
Gary Gardner, Fish Harvest Down, in
Lester R. Brown, et al., Vital Signs 2000: The Environmental
Trends that are Shaping Our Future (New York: W.W. Norton &
Co., 2000).
Anne Platt McGinn, Blue Revolution: The Promises and Pitfalls
of Fish Farming, World Watch, March/April 1998.
Anne Platt McGinn, Safeguarding the Health of Oceans,
Worldwatch Paper 145 (Washington, DC: Worldwatch Institute,
1999).
From Other Sources
United Nations Food and Agriculture Association
(FAO), The State of World
Fisheries and Aquaculture 1998 (Rome: 1999).
Rebecca Goldburg and Tracy Triplett, Murky Waters: Environmental
Effects of Aquaculture in the United States, Environmental
Defense Fund Publication.
Rosamond L. Naylor, et al., Effect of Aquaculture on World
Fish Supplies, Nature,
29 June 2000.
K.J. Rana, FAO Fisheries Department Review of the State of
World Aquaculture: China.
Paul Skillicorn, William Spira and William Journey, Duckweed
Aquaculture: A New Aquatic Farming System for Developing Countries.
The World Bank Technical Working Paper.
LINKS
AquaNIC: Aquaculture Network Information Center
http:/www.aquanic.org
FAO Fisheries Department Homepage
http:/www.fao.org/fi
FIS: Fish Information and Services
http:/www.fis.com
SeaWeb
http:/www.seaweb.org
USDA Aquaculture Reports
http:/usda.mannlib.cornell.edu
|