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The green crab as an invasive species

Carcinus maenas is an example of an invasive species that has induced large, serious changes into the locations it has invaded outside of its natural range in northwestern Europe.

Enormous populations are now found in North America (on both the west and east coasts), South Africa, Tasmania and Australia. It is extensively studied in all these locations because of its negative effect on the valuable mussel farming industry.

In its natural habitat, C. maenas has a number of associated parasites which could potentially limit its popularion size. One of these is a barnacle, Sacculina carcini, which is a parasitic castrator and is found in high numbers in the crab’s natural habitat.

There is a clear relationship between C. maenas and its parasite’s specific biology, but this has not been quantitatively analysed. Such analysis could yield insights that would be beneficial to locations where this invasive species is problematic.