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Environmental questions associated with
mussel cultivation
Mussel cultivation is based upon very little interference in the
environment and is not plagued by the problems that are usually associated
with intensive fish farming. Many feel that the mussel farms are ugly
and a hinder for boat traffic.
Blue mussels eat small particles that are suspended
in the water, which results in the depletion of the amount of plant
plankton that passes the mussel farm. Beneath the farm there is usually
a concentration of organic and inorganic material, the result of the
mussels digestive system that has been released as excrement. When
bacteria under the farm break down this material, a great deal of
oxygen is used and there is an obvious risk that the bottom below
a farm becames oxygen deficient and result in the production of poisonous
hydrogen sulphide. Oxygen deficient bottoms that produce hydrogen
sulphide occur naturally in the sea.
The cultivation of blue mussels appears to only effect
the areas in direct proximity to the farms, but as the amount of waste
increases, the environment and the specie composition changes under
the farms. Animals that once lived on the bottom are replaced by small
animals that live in the surface layers and are not effected by the
deteriorating conditions further down in the sediment. It has been
shown that such bottoms recover rapidly after a mussel farm has closed
or been moved. The large fallout of material and dead or living mussels
beneath the farm also has a positive effect as it attracts a great
many crabs and fish, mainly different specie of flat fish. A mussel
farm results in a large concentration of life within a relatively
little volume of water.
Studies have shown that blue mussels farms can have
a positive effect on the Marine environment, mussels by eating plankton,
bind many nutritive elements that are later harvested from the sea.
This is of interest as large areas of our coastal waters are over
fertilized. In this way, mussels can be used as part of a process
for cleaning coastal waters.
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