Introduction

A necropsy on a Bryde’s whale found dead on Motuihe Island highlights the urgent need to address the ship strike problem.

Date:  15 November 2012

A necropsy on a Bryde's whale found dead on Motuihe Island has confirmed that the whale was hit by a vessel highlighting the urgent need to address the ship strike problem to save the critically endangered population of Bryde's whales in the Hauraki Gulf.

New Zealand is one of the few places in the world with a resident population of Bryde's whale. The New Zealand population of Bryde's whales lives primarily in the Hauraki Gulf and is listed as critically endangered by the Department of Conservation (DOC).This is because its small and reliant for its survival on one location. There are less than 200 Bryde's whales living in the gulf.

The Bryde's whale at Calypso Bay on Motuihe Island during the necropsy. Photo: Phil Brown.
The Bryde's whale at Calypso Bay on Motuihe Island during the necropsy

The dead Bryde's whale was a female measuring 14.5 metres long. It was found on rocks near Wharf Bay on Motuihe on Sunday 11 November. The Department of Conservation (DOC) towed the whale to Calypso Bay on Motuihe, on Monday 12 November.

The necropsy was completed Wednesday 14 November and the whale was buried at Calypso Bay after being blessed by Ngai Tai representatives. Calypso Bay is a suitable site for the necropsy and burial as it's rarely used by visitors to Motuihe and has no archaeological sites.

"The necropsy has confirmed the Bryde's whale was alive when it was struck by a vessel and died as a result of the injuries it received," says DOC Auckland Area biodiversity manager Phil Brown.

"Ship strike poses the greatest threat to Bryde's whales in the Hauraki Gulf Marine Park. This latest death highlights the urgent need to take action to address this problem," says Phil Brown.

In the last 16 years there have been 42 confirmed deaths of Bryde's whales in the Hauraki Gulf. Eighteen of these dead whales were examined and 16 are most likely to have died as the result of being struck by a vessel.

DOC is working with a wide number of organisations and agencies to address the ship strike issue. The Environmental Defence Society, the Hauraki Gulf Forum and the University of Auckland have convened two workshops attended by shipping interests, iwi, DOC and other government agencies to develop a plan of action.

As a result of the workshops DOC is working with shipping representatives and Auckland University marine mammal biologist, Dr Rochelle Constantine to develop practical steps to reduce the risk of ship strike.

The shipping representatives have agreed to implement a number of measures. These include:

  • Slowing their ships down in the Hauraki Gulf when schedules permit.
  • Establishing shipping lanes to reduce the area of the gulf in which ships travel.
    These lanes will be able to be moved away from areas where whales are sighted.
  • Crew watching for whales while their ships move through the gulf during the day.
  • Establishing a Hauraki Gulf Large Whale Warning System. This will involve commercial whale and dolphin watching operators, and other boats in the gulf, reporting whale sightings to Ports of Auckland who relay the sightings to all shipping in the gulf.
  • The shipping industry has agreed to contribute funding for research focusing primarily on ways of reducing ship strike.

Hauraki Gulf Forum Chairman John Tregidga says the ship strike workshops highlighted the critical importance of ship speed to the survival of whales.

"A few large ships travel through the Hauraki Gulf at more than 20 knots. The average speed for large ships in the gulf is 14.2 knots. Scientists have estimated that if this speed was reduced to 10 knots, the Bryde's whale would have a 75% chance of surviving a strike," says John Tregidga.

"I would strongly encourage the industry to establish 10 knots as a code of best practice for the Hauraki Gulf," said John Tregidga.

"It is good to see shipping interests actively engaged in the issue," says Environmental Defence Society Policy Director Raewyn Peart.

"But this latest incident highlights the urgent need for shipping companies to reduce the speed of their vessels before any more whales are killed."

"Research conducted last summer showed that the whales are widely dispersed and shallow divers. They are particularly vulnerable at night when the animals float close to the surface."

"Ship speed is the critical factor in their decline and must be the priority for industry and legislative responses," concluded Raewyn Peart.

Contact

Nick Hirst
Media Advisor
+64 9 307 4866 or +64 27 704 7773

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