Visualizing Environmental Science

Year

Million metric tons of seafood

0

50

100

150

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1950 1960 1970 1980 1990 2000 2010 2020

Aquaculture production

Wild catch

FAO State of World Fisheries and Aquaculture (2012).

Brian J. Skerry /NG Image Collection

b. Cobia are raised in deep-water cages in this underwater fish

farm off Puerto Rico. The open-water circulation reduces the

waste problems common in shallow-water aquaculture.

a. In recent years, fish harvest by aquaculture has continued to

increase, while fishing (wild catch) has leveled off.

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In aquacultural “fish farms,” fish populations are con-

centrated in a relatively small area and produce higher than

normal concentrations of waste that pollute the adjacent

water and harm other organisms. Aquaculture also causes

a net loss of wild fish because many of the fishes farmed are

carnivorous. Sea bass and salmon, for example, eat up to 5 kg

(11 lb) of wild fish to gain 1 kg (2.2 lb) of weight.

Deep-water, offshore aquacultural facilities,

sometimes called “ocean ranches,” are becoming more

common (ˆ}ÕÀiÊ ££°£ÓL). Ocean ranches, which in-

creasingly use cutting-edge technologies such as submers-

ible cages with robotic surveillance, may avoid damaging

coastlines but often lack the pollution- restricting over-

sight associated with other aquaculture operations. Also,

caged populations are more genetically homogenous

than wild ones; if the two groups interbreed, genetic di-

versity of wild populations could be diminished. The in-

troduced organisms may also outcompete wild species.

Shipping, Ocean Dumping,

and Plastic Debris

Millions of ships dump oily ballast and other wastes over-

board in the neritic and oceanic provinces. The U.N.

International Maritime Organization’s International Con-

vention for the Prevention of Pollution from Ships (MAR-

POL) bans marine pollution arising from the shipping

boats of that country are given unrestricted access to

fishes in national waters.

Aquaculture: Fish Farming Aquaculture is more

closely related to agriculture on land than it is to the

fishing industry. Aquaculture

is carried out both in fresh and

marine water; the cultivation of

marine organisms is sometimes

called mariculture. According to

the FAO, growth in world aqua-

culture production outpaced that

of fishing, increasing substantially, from 544,000 metric

tons (600,000 tons) in 1950 to 57.7 million metric tons

(63.6 million tons) in 2011 (ˆ}ÕÀiÊ££°£Ó>).

Aquaculture differs from fishing in several respects.

For one thing, although highly developed nations harvest

more fishes from the ocean, developing nations produce

much more seafood by aquaculture. Developing nations

have an abundant supply of cheap labor, which is a re-

quirement of aquaculture because it is labor intensive,

like land-based agriculture. Another difference between

fishing and aquaculture is that the limit on the size of

a catch in fishing is the size of the natural population,

whereas the limit on aquacultural production is primarily

the size of the area in which organisms can be grown.

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aquaculture

The growing of

aquatic organisms

(fishes, shellfish,

and seaweeds) for

human consumption.

Interpreting Data

During which time periods did aquaculture experience

its most dramatic change?