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The cultivation of blue mussels
Blue mussels in a mussel farm.
Mussel growth occurs mainly between March and December and is dependant
on the availability of food in the surrounding water. Food sources
can be the result of local production or brought to the mussel by
water currents. If the speed of water currents is too low or is poor
in nutrients, there is a risk that the mussel declines in weight because
so much energy is used to filter out the few nutrients that are in
the water.
The blue mussel reaches its maximum size (approx. 10cm)
in salinities of about 3-3,5%.
It is very adaptable and can live in varying salinities, but this
requires energy and results in mussels usually being smaller in size
with lower saline content, for example in the Baltic, where mussels
are seldom larger than 4cm. It was earlier thought that the blue mussel
grew best in water temperatures between 10 - 20°C, but research
has shown that the ocurrence of nutrients is by far the most important
factor and that it can filter and grow in water temeratures down to
-1°C.
A mussel farm needs an area that is pollution free as
they easily absorb poisons and pollutants. The same area should also
have adequate protection against large waves and ice movements. Even
if an area in the outer archipelagos usually means a secure source
of nutrients and fewer pollutants, exposure to current and wave action
poses often too much stress and strain on the equipment.
Blue mussels in Sweden are commonly harvested in November-December
when they are about 1½ years old. If they are allowd to be
older there is a notable increase in the growth of other organisms
on the mussels.
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