Crabs impacting estuary
An unwanted and aggressive Asian paddle crab species has made itself at home in the Ngunguru estuary.
Don McKenzie, Biosecurity Senior Programme Manager for the Northland Regional Council, says Asian paddle crabs ’Charybdis japonica’ were discovered in the estuary by a member of the public in late 2014.
Since then more than a dozen have been seen.
‘‘We’re unsure how these paddle crabs have ended up in Northland, although the most likely scenario is they arrived as an unwanted hitchhiker on a fouled boat hull or in ballast water from other parts of New Zealand,’’ he says.
McKenzie says what is known about the crabs is they are an added threat to our already vulnerable bivalve molluscs like pipi and cockles, which they feed on. They also compete with our native crabs.
McKenzie says council’s biosecurity team has been investigating the best way to trap the crabs to try and limit their spread.
‘‘Long-term trapping may be a way of at least reducing the impact of these crabs,’’ he says.
He encourages any one catching them to kill them.