A species of crab described as "nasty pieces of work" has become well established in Tauranga Moana and further along the Bay of Plenty coast.
Bay of Plenty Regional Council said underwater trapping across the coastline this summer had confirmed the spread of the aggressive Asian paddle crab.
Biosecurity officer Andy Wills said it was a disappointing result for local hapū, harbour users and the council alike describing the crab as "nasty pieces of work".
"They have a huge appetite, feeding on shellfish such as pipi, tua tua and cockles - threatening kaimoana (seafood) stocks and potentially mussel farms in the region.
"They are also far more aggressive than your average native crab and can inflict a vicious bite with their large pincers if disturbed," Wills said.
The crabs were first found in Tauranga Harbour in January 2018 when two were caught near Matapihi Bridge. After the discovery almost 1200 traps were placed around the harbour, last summer catching just eight crabs.
This summer 42 were caught in Tauranga Harbour and for the first time two crabs were also caught in Ōhiwa Harbour.
"It's not known how the pest originally spread to the region, but it's likely that they either swam, floated here or hitched a ride on a fouled hull from further north. Asian paddle crabs are already widespread in Northland and the Hauraki Gulf," Wills said.
The council said they were looking to work with local hapū kaitiaki in Tauranga Moana and Ōhiwa Harbour to help with further detection and control efforts as well as supporting a project being co-ordinated by Manaaki Te Awanui to explore options for trialling matāuranga Māori-based trapping methods.
Harbour users are encouraged to keep their boats clean and keep an eye out for Asian paddle crabs. They should be killed on site and reported via 0800 STOP PESTS (0800 786 773). It is illegal to move living pest crabs.