Geoscience Reference
In-Depth Information
Table 11-3.
Aquaculture production for i sh, crustaceans and mollusks by top 5 producing countries. Source: Food
and Agriculture Organization. 2009.
Yearbook of Fishery Statistics 2007
. Accessed online
<
ftp://ftp.fao.org/docrep/
fao/012/i1013t/i1013t.pdf
>
October 2010.
Country
1998 (tons)
1998 (%)
2002 (tons)
2002 (%)
2007 (tons)
2007 (%)
China
18,721,938
66.0
24,141,658
65.6
31,420,275
62.4
India
1,908,485
6.7
2,187,189
6.0
3,354,754
6.7
Vietnam
338,920
1.2
703,041
1.9
2,156,500
4.3
Indonesia
629,797
2.2
914,071
2.5
1,392,904
2.8
Thailand
594,579
2.1
954,696
2.6
1,390,031
2.8
Total
22,193,719
78.1
28,900,655
78.6
39,714,464
78.9
pond i sh culture along river l oodplains and in
l ooded rice paddies, have contributed to China's
leading position in aquaculture production.
With increasing demand, aquaculture is
poised to grow even more rapidly in the coming
years. Shrimp cultivation is the largest by value,
accounting for roughly 15 percent of the traded
volume of all seafood. It is often undertaken in
coastal brackish wetlands or constructed ponds
pumped with sea water. For many countries, the
export value of seafood now far outstrips tradi-
tional commodities like rice, tea, etc. In the
United States alone, aquaculture production was
valued at US$87 billion in 2007 (Food and Agri-
culture Organization 2009). In comparison, the
total retail equivalent value of the United States
beef industry was US$76 billion for 2007 (U.S.
Department of Agriculture 2010d).
Given these trends, scientists have voiced
concern over the ramii cations of this growth
industry on wetland ecosystems worldwide.
Studies have documented the potential negative
effects of large commercial-scale aquaculture
undertakings on ecosystems including wetlands
(Alongi 2002; Seto and Fragkias 2007). These
include the:
• Dilution of wild i sh stock with the acciden-
tal introduction of genetically modii ed
farmed species.
As this section suggests, primary sector extrac-
tive industries may have potentially quite dam-
aging consequences for wetland ecosystems.
While it would be impractical to prevent the use
of these resources, the focus should be on more
sustainable extraction and wise-use practices,
which has been the call of organizations like
Ramsar.
11.4.2 Pearl production
Pearls are beautiful gemstones created by mol-
lusks located in fresh- and salt-water wetlands.
Chapman (2009) recognized 85,000 extant
species of mollusks. However, only 20 mollusk
species are pearl-bearing, and of those six are
responsible for the overwhelming majority of
today's cultured-pearl production (Table 11-4).
The majority of marine pearls come from the
akoya pearl (
Pinctada fucata
), golden- and
silver-lipped pearl (
P. maxima
), and black-
lipped pearl (
P. margaritifera
) from Japan and
tropical South Sea regions; whereas the majority
of fresh-water pearls come from the triangle
shell (
Hyriopsis cumingii
) and wrinkle shell
(
Cristaria plicata
) in Asia; the washboard shell
(
Megalonaias nervosa
) is from North America.
Natural pearls are rare, and gem quality ones
especially rare. The Abernethy Pearl, for instance,
is a large gem-quality fresh-water pearl from
Margaritifera margaritifera,
discovered in 1967
in the River Tay in Scotland. One of the most
threatened fresh-water species worldwide,
M.
• Clearing of coastal mangroves to make way
for shrimp farms.
• Pollution from waste and other chemicals
and pharmaceuticals used in intensive aqua-
culture, which may lead to eutrophication
and algal blooms.
• Upsurge of i sh diseases and parasites such
as sea lice that thrive under contained condi-
tions often found at large aquaculture sites
or in i sh pens and cages.
