Post mortem results confirm rare whale was sick

5 March 2009

Post mortem results confirm rare whale was sick

Post mortem results have revealed that the rare Gray’s beaked whale euthanised on a Whangaparaoa beach on Saturday was indeed in very poor health, with severe emaciation and muscle wasting evident.

The post mortem was carried out by marine experts from Massey University led by Dr Karen Stockin.

The whale, a juvenile 3.7 metre male, was found to have a diminished blubber layer, representing roughly half the thickness of what would be expected in a healthy animal. The post mortem also showed that the animal had not fed in the days prior to its death. Also several ulcers were evident along its oesophagus. Further tests are currently underway to determine the cause of severe congestion also found in the whale’s liver.

Liz Maire, DOC Community Relations Programme Manager says the findings prove that the decision taken not to attempt to refloat this stranded animal was in the animal’s best interests.

“DOC only refloats stranded marine mammals when the animal is in good health. Sadly this was not the case and the post mortem has confirmed how sick this animal was. He would have been highly likely to restrand, causing further stress and injury, and really just prolonging the inevitable.”

Ms Maire says that relocating the whale to deep water was also a choice that could have led to further suffering for the animal. “Stranded or not, this whale would have been difficult to move and the process very stressful for an animal already in poor health”.

“Euthanising the whale at sea was not a viable or humane option either. Trying to shoot a moving whale would have been very difficult and may only have injured it and caused further suffering”.

The whale had been monitored for 3 weeks off Stanmore Bay Beach by DOC staff, Project Jonah volunteers and Massey University scientists. Massey University biologist Dr Karen Stockin says the post mortem confirmed earlier field observations that the animal was very thin and had rapidly lost condition.

The whale did much to endear itself to all those involved. “I totally understand why the public are upset. From their perspective shooting a whale is not ‘conservation’ however the whale’s welfare was our top priority.” says Dr Stockin.

Despite the sad ending to this event, the occurrence of a live beaked whale in coastal waters enabled many local people to have a close and special encounter with a rare marine species, something many marine scientists have never achieved. Whales of this species are rarely seen off New Zealand’s coast as they are deep ocean creatures, diving for soft bodied animals like squid. Anton van Helden, a New Zealand expert on beaked whales, has studied them for 20 years and never actually seen one alive.

Note
It is illegal to swim with whales in New Zealand waters and boaties need to move slowly and stay at least 50m away.

Facts about Gray’s beaked whales Mesoplodon grayi

• They have a national DOC threat classification of 'data deficient' because so little is known about them.

• Gray’s beaked whales are also known as Scamperdown whales.

• They typically grow to about 5.5m long.

• Most have tiny maxillary teeth in upper jaw, but the adult males have two exposed tusks/teeth in the lower jaw (one on each side), while females will have a small tooth that is not exposed above the gum line.

• They are the most common species of beaked whale that strand in New Zealand and the only species of beaked whale that is known to mass strand.

• They were first described by Julius von Haast after a stranding of 28 animals in the 1860s on the Chatham Islands.

• There are 21 species of beaked whale that are currently recognised worldwide, of which 12 occur in New Zealand waters. Five of the 21 species were first described from animals stranded in NZ.

• With a few exceptions, many of the species are known from only a handful of specimens.

• NZ has the greatest number of different species of beaked whales in the world.

• They are rarely seen at sea because of their elusive habits, preference for deep ocean waters and possible low abundance. Most of what is known about them has come from strandings.

• They are usually seen single, in pairs or in small groups.

• They are deep divers and feed largely on soft bodied animals like squid.

More information about Gray’s beaked whales can be found on the Te Ara website: http://www.teara.govt.nz/EarthSeaAndSky/SeaLife/Whales/7/en

ENDS

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