February 1, 2012

Endangered Bryde’s whale dies in Hauraki Gulf after apparent ship strike

A necropsy on an endangered Bryde’s whale found floating in the Hauraki Gulf Marine Park has shown that the whale was alive when it appears to have been hit by a vessel.

The population of Bryde’s whales living in New Zealand waters is critically endangered. New Zealand is one of the few places in the world where there’s a resident population of Bryde’s whale. It is centred on the Hauraki Gulf. Fewer than 200 Bryde’s whales frequent the gulf.

The dead Bryde’s whale was seen by members of the public floating near Waiheke Island and reported to the Department of Conservation. DOC rangers recovered the

whale floating north east of Tiri Tiri Matangi on Monday (January 29). They towed it to Motuihe Island which is managed by DOC in partnership with the Motuihe Trust.

The necropsy was performed at Calypso Bay on Motuihe Island. The bay is at the opposite end of the island to where the ferries berth. It was chosen as a suitable site

for the necropsy as its rarely used by visitors to Motuihe and there are no archaeological sites.

The 15 metre long female whale was buried at Calypso Bay last night after the necropsy was completed using two earth moving machines and a bulldozer that are on Motuihe for road building work. Representatives of Ngati Paoa blessed the whale and the burial site.

The necropsy was led by Massey University veterinary pathologist Stuart Hunter assisted by veterinarians from the New Zealand Centre for Conservation Medicine at Auckland Zoo.

“The necropsy has shown that the whale was alive when it was struck, most probably by a vessel,” says DOC Auckland Area biodiversity manager Phil Brown.

“We’re waiting for the full results of the necropsy to determine if ship strike was the exact cause of the whale’s death.”

In the last 16 years there have been 41 confirmed deaths of Bryde’s whales in the Hauraki Gulf. Eighteen of these dead whales were examined and 15 are most likely to have died as the result of being struck by a vessel.

Ship strike poses the greatest threat to Bryde’s whales in the Hauraki Gulf and DOC is working with the University of Auckland on the issue.

“We’re concerned about the number of Bryde’s whales being struck by vessels,” says Phil Brown.

“One of the things that could be done to protect these whales is to lower the speed of commercial ships passing through the Hauraki Gulf Marine Park.”

“This happens in other places around the world so we know that shipping companies are used to taking this sort of measure.”

Dr Rochelle Constantine and Dr Natacha Aguilar from the University of Auckland are leading research into why Bryde’s whales are so vulnerable to being struck by vessels.

Dr Constantine says preliminary analysis of the research shows that the whales are spending the majority of their time less than ten metres below the surface. This puts them within the strike depth of many vessels using the Hauraki Gulf.

“We’ve been talking to the shipping industry about the threat vessels pose to Bryde’s whales in the Hauraki Gulf,” says Dr Constantine.

“We’re getting positive feedback from the shipping industry in our discussions on measures to protect the critically endangered population of Bryde’s whales living in the Hauraki Gulf.”
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