Fears for orca whales in harbour plan

A quarter of New Zealand's orca use the harbour for feeding and sleeping; and, below, injuries from boat strikes are visible on an orca. Photo / Amos Chapple

But Ports of Auckland dismisses scientist’s warnings about impact on whales.

Proposed Auckland port developments could be a killer blow for the harbour's already endangered New Zealand orca population, a wildlife expert fears.

Ports of Auckland wants to build two 100m extensions from the end of Bledisloe Wharf and eventually reclaim 3ha of seabed between them, a move which has sparked fierce public backlash.

Orca Research Trust founder and principal scientist Dr Ingrid Visser feared a narrower Waitemata Harbour would make boat strikes more common and increased noise could put the endangered mammals off entering a vital feeding and sleeping area.

But Ports of Auckland spokesman Matt Ball said Visser was being "alarmist" and her statements were misleading.

New Zealand orca produce on average just four calves in their lifetime, half of which die before reaching adulthood.

Visser said a quarter of the estimated 200 orca population used the harbour and she was aware of six strikes in the past 20 years. The waterway was vital to the mammals' survival. "They have to travel big distances to get to food, they rely on patchy food sources. This isn't a matter of 'let's grab a burger', it's 'I need enough food to survive, to feed my babies, to produce enough milk so my babies are going to survive'."

New Zealand orca produce on average just four calves in their lifetime, half of which die before reaching adulthood. Visser also feared dredging could disturb pollutants from anti-fouling and other toxins on the sea floor, which could enter the food chain.

New Zealand Orca already had the highest chemical loading of any animal measured in the Southern Hemisphere, she said. "These animals have so many things happening against them and this would just be another. It may be the straw that breaks the camel's back."

Ball said Ports of Auckland had worked with scientists over development plans and were aware of the potential impact. He said the footprint of the extensions was tiny compared to the 18,000ha harbour.

"The location is neither critical habitat nor a primary feeding ground. The wharf extensions are unlikely to have any impact on orca reproduction or mortality."

No dredging was associated with the wharf extension, and maintenance dredging would remove historic pollution. Underwater noise was considered as part of the resource consent for the extensions and bored piling did not generate percussive impact noise.

Ships travelled slowly in the harbour, so there was no risk of strikes, and there would not be more ships in the harbour. Ball said there would be fewer, larger ships - and said the extensions would not make the harbour narrower.