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Overview:
Aquaculture, also known as fish
farming, is the process of raising freshwater or saltwater organisms
for food production. These practices date back as much as 3500
years when the Chinese began to hold carp in fishponds for consumption
purposes. The popularity and extent of use of aquaculture has changed
overtime depending on the necessity of local people. Today
aquaculture has grown into big business and accounts for nearly one
third of world seafood production by mass. A number of
environmental questions have risen from the explosion of aquaculture on
an industrial scale of the past 40 years.
Aquaculture can be broken down into two main
systems, open and closed. An open system is a system that is open to
the sea and that takes advantage of the currents and nutrients in the
environment. Closed systems are those systems that have no direct
contact with the open sea and are often run in structures that are
built on land to house fish and shellfish.
General Concerns
Involving Aquaculture:
Pollution:
Aquaculture, especially that of the intensive variety puts a high
concentration of animals in a small area. The waste products of
these animals can pollute the environment whether it be open oceans, a
stream or a closed pond. If the waste is not treated effectively
it can be hazardous to the ecosystem, health of wild animals and human
health.
Dependence on the
Wild:
It is a misconception that farming fish relieves the stress on wild
stocks because carnivorous species raised by aquaculture practices
still need to eat protein obtained from wild fish. In the case of
salmon they consume 3kgs of wild fish for every 1kg of flesh they
produce. Also some fisheries are dependent on wild stocks for
their juveniles.
Disease:
The stocking densities in aquaculture are much higher than those that
occur in the natural world. These conditions mean that disease
and parasite can easily be transferred between fish. Currently,
many diseases are controlled by an extensive system of vaccines and
antibiotics, however this has a two-fold effect on the
environment. First, the fish that we eat will have antibiotics in
it and the side effects to humans over the long term are unknown.
Secondly, the use of such drugs help to breed super diseases that are
antibiotic resistance and could poses threats to wild stocks.
Escapes:
Escaped farmed fish, especially salmon, can cause major environmental
problems. The major concern is their interaction with wild
populations, which in the case of Atlantic Salmon, is endangered.
Farmed salmon have a very limited gene pool and can dilute the wild
gene pool through interbreeding. Escaped fish can also compete
for resources in an environment where they might not naturally be
found, creating an ecological imbalance.
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