Humpbacked visitor drifts into NZ

By DANIEL JACKSON

A lobster considered too ugly to eat has been identified as a tropical species that has hitch-hiked its way to New Zealand.

Divers found the strange lobster, which has bony plates at the front instead of antennae and large bumps on its back, nearly a year ago while crayfishing in a cave about 30m underwater at the Whangarei Heads.

They had planned to eat it but decided it was too ugly and took it to the Whangarei Museum of Fishes instead.

Museum owner George Campbell said he initially thought it was a mutant Spanish lobster, which are found in New Zealand waters but are much smaller.

However, marine biologist Dr John Booth, from the National Institute of Water and Atmospheric Research, has now identified it as a Scyllarides haanii, otherwise known as a humpbacked slipper lobster, which is most commonly found in tropical regions.

He said it probably drifted several thousand kilometres south as a larva on warm ocean currents before finding a spot to establish itself off Northland.

"We've heard of them in the Kermadec Islands before but this is the first record of one in mainland New Zealand."

Dr Booth said the lobster was the largest type of slipper lobster and could grow to about half a metre in length. It probably fed on shellfish and whatever other high protein things it could find.

He said the lobster appeared to be an adult female but doubted it had been able to breed here because of the lack of suitable mates. "They are extremely rare and the numbers are so low as to be of no consequence."

While it was interesting to find the lobster so far south from its normal habitat it was not unprecedented as other warm-weather creatures had caught rides on ocean currents before, he said.

"Along the east coast of Northland we always get a smattering of tropical species from time to time."

Mr Campbell said learning the lobster was a tropical species solved the riddle of why it was acting sluggishly in cold water. He had since warmed its tank to about 22 degrees.

"It went through last winter with no heating at all and we were getting worried it was going to die," he said.

Since the tank water was warmed the lobster had become more lively and had shed its shell while growing larger.