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UNIT 4
AQUACULTURE
TEXT 17
INTRODUCTION
Aquaculture is the rearing of aquatic organisms under controlled conditions. More
simply, aquaculture is underwater agriculture. The concept is not a new one-fish cul-
ture began in China perhaps as much as 4000 years ago. The Egyptian tombs have
pictographs indicating that certain types of fishes were being reared during the days
of the Pharoahs, and oyster culture was being practiced under the Roman Empire.
Most
people think of acquaculture as the production of aquatic animals for human con-
sumption, and many of the aquaculture effors around the world are being conducted
for that purpose. There are, hourever, other purposes for which aquatic organisms are
grown. Examples include producing minnows for bait, rearing tropical fishes and
gold fish for the aquarium trade and producing ornamental aquatic plants (water
liles).
In addition, the often large-scale hatchery programs that exist in the various states
and provinces of North America and throughout the world produce fishes for release
into streams, lakes, reservoirs and the marine environment to enhance commercial
and recreational fisheries as well as to repopulate water bodies with endangered and
threatened species. Aquatic plants are also produced for human consumption. In the
Orient, for example, seaweed production (e.g., red and brown algae) involves the la-
bour of several hundreds of thousands of people. The seaweeds may be consumed di-
rectly by man or extracts may be obtained that become components of a variety of
substances each of us uses every day. Ice cream, toothpaste, cosmetics and a wide
range of other house hold items contain extracts from seaweeds. Some of those busi-
nesses are very large, and they are legitimate aquaculture enterprises. Under natural
conditions, as much as 100 pounds per acre (kg/ha) of fish might be produced in a
lake within a year. Aquaculture systems, by contract, can produce several thousand to
even a million pounds per acre (kg/ha) in a year: The difference relates to the defini-
tion of aquaculture presented above. The aquaculturist exerts control over the species
being reared. That control may include, but is not limited to the following:
1. Design, construction and maintenance of the culture system being employed.
Aquaculturists utilize ponds, cages, net-pens, race ways, tanks and other units. They
do not attempt to convert unaltered natural water bodies into culture system.
2. Maintenance of suitable water quality. In order foran aquaculture venture to be
successful, the water must be of a quality suitable for the species being reared. Of
most importance are the levels of dissolved oxygen and ammonia, water temperature
44
UNIT 4
AQUACULTURE
TEXT 17
INTRODUCTION
Aquaculture is the rearing of aquatic organisms under controlled conditions. More
simply, aquaculture is underwater agriculture. The concept is not a new one-fish cul-
ture began in China perhaps as much as 4000 years ago. The Egyptian tombs have
pictographs indicating that certain types of fishes were being reared during the days
of the Pharoahs, and oyster culture was being practiced under the Roman Empire.
Most
people think of acquaculture as the production of aquatic animals for human con-
sumption, and many of the aquaculture effors around the world are being conducted
for that purpose. There are, hourever, other purposes for which aquatic organisms are
grown. Examples include producing minnows for bait, rearing tropical fishes and
gold fish for the aquarium trade and producing ornamental aquatic plants (water
liles).
In addition, the often large-scale hatchery programs that exist in the various states
and provinces of North America and throughout the world produce fishes for release
into streams, lakes, reservoirs and the marine environment to enhance commercial
and recreational fisheries as well as to repopulate water bodies with endangered and
threatened species. Aquatic plants are also produced for human consumption. In the
Orient, for example, seaweed production (e.g., red and brown algae) involves the la-
bour of several hundreds of thousands of people. The seaweeds may be consumed di-
rectly by man or extracts may be obtained that become components of a variety of
substances each of us uses every day. Ice cream, toothpaste, cosmetics and a wide
range of other house hold items contain extracts from seaweeds. Some of those busi-
nesses are very large, and they are legitimate aquaculture enterprises. Under natural
conditions, as much as 100 pounds per acre (kg/ha) of fish might be produced in a
lake within a year. Aquaculture systems, by contract, can produce several thousand to
even a million pounds per acre (kg/ha) in a year: The difference relates to the defini-
tion of aquaculture presented above. The aquaculturist exerts control over the species
being reared. That control may include, but is not limited to the following:
1. Design, construction and maintenance of the culture system being employed.
Aquaculturists utilize ponds, cages, net-pens, race ways, tanks and other units. They
do not attempt to convert unaltered natural water bodies into culture system.
2. Maintenance of suitable water quality. In order foran aquaculture venture to be
successful, the water must be of a quality suitable for the species being reared. Of
most importance are the levels of dissolved oxygen and ammonia, water temperature
44
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