A successful invader

In the year 2000, the Asian paddle crab Charybdis japonica, which is foreign to New Zealand, was discovered in flounder nets set in Waitemata Harbour, in Auckland. Foreign invaders are quite often found in the water intakes of visiting ships, but usually don't survive here. Not so the Asian paddle crab.

Since its discovery ten years ago the crab has established itself in Waitemata Harbour and can be found up to 30 km north and south of the Harbour entrance. It prefers firm to muddy sand and is found in estuaries and shallow coastal areas.

Charybdis japonica grows to about the same size as our common local paddle crab, Ovalipes catharus, but is a far more aggressive species and causes difficulties for flounder fishers. Since the Asian paddle crab has invaded other countries besides New Zealand, experiments have been carried out in Japan to see if the species could become a fishery.