This
article is about the farming of marine (saltwater) shrimps.
For farming of fresh water species, see freshwater prawn farming.
A
steamed tail-on shrimp. |
A shrimp farm is an aquaculture business designed to raise
and produce marine shrimp or prawns1 for human consumption.
Commercial shrimp farming began in the 1970s, and production
grew steeply, particularly to match the market demands of
the USA, Japan and Western Europe. The total global production
of farmed shrimp reached more than 1.6 million tonnes in 2003,
representing a value of nearly 9 billion U.S. dollars. About
75% of farmed shrimp is produced in Asia, in particular in
China and Thailand. The other 25% is produced mainly in Latin
America, where Brazil is the largest producer. The largest
exporting nation is Thailand.
Shrimp farming has evolved from traditional, small-scale businesses
in Southeast Asia into a global industry. Technological advances
have led to growing shrimps at ever higher densities, and
broodstock is shipped world-wide. Virtually all farmed shrimp
are penaeids (i.e., shrimps of family Penaeidae), and just
two species of shrimp—the Pacific White Shrimp and the
Giant Tiger Prawn—account for roughly 80% of all farmed
shrimp. These industrial monocultures are very susceptible
to diseases, which have caused several regional wipe-outs
of farm shrimp populations. Increasing ecological problems,
repeated disease outbreaks, and pressure and criticism from
both NGOs and consumer countries led to changes in the industry
in the late 1990s and generally stronger regulation by governments.
In 1999, a program aimed at developing and promoting more
sustainable farming practices was initiated, including governmental
bodies, industry representatives, and environmental organizations.
History and geography
Shrimp farming has been done for centuries in Asia, using
traditional low-density methods. Indonesian brackish water
ponds called tambaks can be traced back as far as the 15th
century. Shrimps were farmed on a small scale in ponds, in
monocultures or together with other species such as milkfish,
or in rotation with rice, using the rice paddies for shrimp
cultures during the dry season, when no rice could be grown.
Such traditional cultures often were small operations in coastal
areas or on river banks. Mangrove areas were favoured because
of their naturally abundant supply of shrimps. Wild juvenile
shrimps were trapped in ponds and reared on naturally occurring
organisms in the water until they had the desired size and
then were harvested.
The origins of industrial shrimp farming can be traced back
to the 1930s, when Kuruma shrimp (Penaeus japonicus) was spawned
and cultivated for the first time in Japan. By the 1960s,
a small shrimp farming industry had appeared in Japan. Commercial
shrimp farming began in the late 1960s and early 1970s. Technological
advances led to ever more intensive forms of shrimp farming,
and the growing market demand led to a proliferation of shrimp
farms throughout the world, concentrated in tropical and sub-tropical
regions. The growing consumer demand coincided in the early
1980s with faltering wild shrimp catches, creating a veritable
boom in shrimp aquaculture. Taiwan was amongst the early adopters
and a major producer in the 1980s; its production collapsed
beginning in 1988 due to poor management practices and disease.
In Thailand, large-scale intensive shrimp farming expanded
rapidly from 1985. In South America, shrimp farming was pioneered
by Ecuador, where it expanded dramatically from 1978. Brazil
had been active in shrimp farming since 1974, but the trade
really boomed there only in the 1990s, making the country
a major producer within a few years. There are marine shrimp
farms in over fifty countries.
Farming methods
When shrimp farming emerged in the 1970s as an economically
viable alternative to satisfy growing market demands which
had surpassed the capacity of the wild shrimp fishery, the
subsistence farming methods of old were rapidly replaced by
the more intensive practices of an export-oriented business.
Industrial shrimp farming at first followed these traditional
methods with so-called extensive shrimp farms, but compensated
for the low yield per area with increased pond sizes: instead
of ponds of just a few hectares, ponds of sizes up to 100 ha
(one kmĘ) were used in some places. The initially largely
unregulated business boomed, and in many regions whole coastlines
were transformed and huge areas of mangroves cleared. Further
technological advances made more intensive farming practices
possible that could achieve higher yields per area while using
less land. Semi-intensive and intensive farms appeared, where
the shrimps were reared on artificial feeds and ponds were
actively managed. Although there are still many extensive
farms, new farms typically are of the (semi-)intensive kind.
Until the mid-1980s, most shrimp farms were stocked with young
wild shrimps, called postlarvae, typically caught by local
fishermen. Postlarvae fishing became an important economic
sector in many countries. To counteract the beginning depletion
of fishing grounds and to ensure a steady supply of young
shrimps to farms, the industry started raising shrimps from
the egg and maintaining adult shrimps for reproductive purposes
in specialized installations called hatcheries.
Life cycle of shrimps
Shrimps mature and breed only in a marine habitat. The females
lay 50,000 to 1 million eggs, which hatch after some 24 hours
into tiny nauplii. These nauplii feed on yolk reserves within
their body and then undergo a metamorphosis into zoeae. This
second larval stage feeds in the wild on algae and after a
few days metamorphoses again into the third stage to become
myses. The myses already look akin to tiny shrimps and feed
on algae and zooplankton. After another three to four days
they metamorphose a final time into postlarvae: young shrimps
having all the characteristics of adults. The whole process
takes about 12 days from hatching. In the wild, the postlarvae
then migrate into estuaries, which are rich in nutrients and
low in salinity. There they grow and eventually migrate back
into open waters when they mature. Adult shrimps are benthic
animals living primarily on the sea bottom.
Farmed species
Although there are many species of shrimp and prawn, only
a few of the larger ones are actually cultivated, all of which
belong to the family of penaeids (family Penaeidae), and within
it to the genus Penaeus3. Many species are unsuitable for
farming: they are too small to be profitable, or simply stop
growing when crowded together, or are too susceptible to diseases.
The two species dominating the market are:
* Pacific White Shrimp (Penaeus vannamei, also called "Whiteleg
Shrimp") is the main species cultivated in western countries.
Native to the Pacific coast from Mexico to Peru, it grows
to a size of 23 cm. P. vannamei accounts for 95% of the
production in Latin America. It is easy to breed in captivity,
but succumbs to the Taura disease.
* Giant Tiger Prawn (P. monodon, also known as "Black
Tiger Shrimp") occurs in the wild in the Indian Ocean
and in the Pacific Ocean from Japan to Australia. The largest
of all the cultivated shrimp, it can grow to a length of 36 cm
and is farmed in Asia. Because of its susceptibility to the
Whitespot disease and the difficulty of breeding it in captivity,
it is gradually being replaced by P. vannamei since 2001.
Together,
these two species account for about 80% of the whole farmed
shrimp production.[Jos04, p.8] Other species being bred
are:
Kuruma
shrimps in an aquaculture observation tank in Taiwan.
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* Western Blue Shrimp (P. stylirostris) was a popular choice
for shrimp farming in the western hemisphere, until the IHHN
virus wiped out nearly the whole population in the late 1980s.
A few stocks survived and became resistant against this virus.
When it was discovered that some of these were also resistant
against the Taura virus, some farms again bred P. stylirostris
from 1997 on.
* Chinese White Shrimp (P. chinensis, also known as the Fleshy
Prawn) occurs along the coast of China and the western coast
of Korea and is being farmed in China. It grows to a maximum
length of only 18 cm, but tolerates colder water (min.
16°C). Once a major factor on the world market, it is
today used almost exclusively for the Chinese domestic market
after a virus disease wiped out nearly all the stocks in 1993.
* Kuruma Shrimp (P. japonicus) is farmed primarily in Japan
and Taiwan, but also in Australia; the only market is in Japan,
where live Kuruma shrimps reach prices of the order of US$
100.– per pound.
* Indian White Shrimp (P. indicus) is a native of the coasts
of the Indian Ocean and is widely bred in India, Iran and
the Middle East and along the African shores.
* Banana Shrimp (P. merguiensis) is another cultured species
from the coastal waters of the Indian Ocean, from Oman to
Indonesia and Australia. It can be grown at high densities.Several
other species of Penaeus play only a very minor role in shrimp
farming. Some other kinds of shrimp also can be farmed, e.g.
the "Akiami paste shrimp" or Metapenaeus spp. Their
total production from aquaculture is of the order of only
about 25,000 tonnes per year, small in comparison to that
of the penaeids.
Economy
The total global production of farmed shrimp reached more
than 1.6 million tonnes in 2003, representing a farm-gate
value of nearly 9,000 million U.S. dollars.[FIGIS] This accounts
for 25% of the total shrimp production that year (farming
and wild catches combined).[Jos04, p.9] The largest market
for shrimp is the United States, importing more than 500,000
tonnes of shrimp in 2003. About 250,000 tonnes went to Japan,
while the four major European shrimp importing countries (France,
Spain, the UK, and Italy) imported together about another
500,000 tonnes.
The import prices for shrimp fluctuate wildly. In 2003 the
import price per kilogram shrimp in the United States was
US$ 8.80, slightly higher than in Japan at US$8.–. The
average import price in the EU was only about US$5.–/kg;
this much lower value is explained by the fact that the EU
imports more coldwater shrimp (from catches) that are much
smaller than the farmed warm water species and thus attain
lower prices.[Jos04, p.16]
About 75% of the world production of farmed shrimp comes from
Asian countries; the two leading nations being China and Thailand,
closely followed by Vietnam, Indonesia, and India. The other
25% are produced in the western hemisphere, where the South-American
countries (Brazil, Ecuador, Mexico) dominate. In terms of
export, Thailand is by far the leading nation with a market
share of more than 30%, followed by China, Indonesia, and
India, accounting each for about 10%. Other major export nations
are Vietnam, Bangladesh, and Ecuador.[FM] Thailand exports
nearly all of its production, while China uses most of its
shrimp in the domestic market. The only other major export
nation that has a strong domestic market for farmed shrimps
is Mexico.
See also:
• Freshwater prawn farming shares many characteristics
and problems with marine shrimp farming. Unique problems are
introduced by the main species' (the Giant River Prawn, Macrobrachium
rosenbergii) developmental life cycle.[New02] The global annual
production of freshwater prawns (excluding crayfish and crabs)
in 2003 was about 280,000 tonnes, of which China produced
some 180,000 tonnes, followed by India and Thailand with some
35,000 tonnes each. China also produced about 370,000 tonnes
of Chinese River Crab (Eriocheir sinensis).
•
Shrimp fishery
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