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Threats against mussel farms
In Swedish waters the most serious competitor for food and space
is the sea squirt Ciona intestinalis. If the blue mussels are
not harvested within two years, large growths of sea squirts cause
great problems. The sea squirt lives as a larva only a short period
and the young colonize areas close to adults of the same species.
Other organisms that grow on mussel farms are barnacles and polychaetes
such as Pomatoceros triqueter.
Sea squirts.
Regarding predators, crabs and starfish are seldom a problem as long
as the ropes do not come in contact with the bottom, but with bottom
cultivation, crabs, starfish, crows, eiders, gulls and oystercatchers
are a threat. In the Netherlands, starfish are a problem and results
in the use of special rollers that scrape them way. If mussels and
starfish are scraped up at the same time, the starfish die after a
short period of time in the air, while the mussels can be sown again
on the bottom.
Dutch mussel scraper.
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