Shipping companies have agreed to slow down and alter course in the Hauraki Gulf in an effort to save an endangered resident whale.

A protocol between Ports of Auckland and the shipping industry aims to reduce fatalities from ship strikes, which take a significant toll on New Zealand's Bryde's whale population and other marine mammals.

The deal agreed to this week is the culmination of a six-year campaign led by Auckland University marine biologist Rochelle Constantine, whose research, including full necropsies on washed-up carcasses, highlighted the contribution of ship strikes to the Bryde's whale's plight.

Ships are expected to post whale lookouts during daylight, slow down in areas where the Bryde's whales gather, stick to recommended routes, steer 1km clear of sighted whales and report sightings so other ships can be alerted. They are also urged to avoid the channel between Little Barrier and Great Barrier Islands, a hotspot for whales and dolphins.


While voluntary, the protocol was developed with industry input and, based on similar agreements overseas, is expected to be well supported.

"The last thing that anyone on a ship wants to do is kill a whale," says Andy Mitchell, operations manager for vehicle and heavy cargo carrier Armacup.

Reducing speed from the customary 15 knots to a desired 9 or 10 knots is expected to greatly improve survival chances if whales are struck. The move will add up to 1 hours to transit times, time which can't be made up on short coastal hauls such as Auckland-Tauranga. Mr Mitchell said running ships at slower than their design speed also meant more work for the crew and possible additional costs. "But if we can take some measures to reduce the risk to these whales then we are keen to do so."

Bryde's whales are thought to congregate in the gulf because of plankton, krill and small fish. But habits which include lurking just below the surface and spending long periods resting at night make them vulnerable to commercial and cruise ship traffic.

No more than 200 are thought to be left in NZ waters and records suggest at least two a year are dying due to ship strike. Ports of Auckland chief executive Tony Gibson said the protocol stemmed from a collaborative effort involving shipping companies, university researchers, the Department of Conservation, Hauraki Gulf Forum and Environmental Defence Society. He praised Dr Constantine's pragmatic approach for the eventual agreement.

The port company is also contributing $30,000 to a year-long project using aerial surveys to count and map the distribution of whales and other marine mammals, which may lead to further changes in shipping routes. High-tech warning systems are also being investigated.

Gulf forum chairman John Tredidga congratulated the industry and port company.

"There is good scientific evidence that 10 knots is a safe travelling speed around whales."