Scientists gather to catch rare slice of killer whale's life
BY PAUL EASTON
A rare chance to carry out an autopsy on a baby orca could reveal more about the species and the health of the ocean environment.
The newborn died in 2007 soon after it was washed on to Waita Beach, 10 kilometres north of Haast in Westland. It had been kept frozen till Canadian scientist Stephen Raverty was available.
This week he and other scientists met in Wellington to photograph and dissect the orca at Te Papa's Tory St laboratory. Te Papa marine mammal expert Anton van Helden said that slicing into the orca's blubber layer was like "cutting into butter". The layer was thick, meaning the orca had not starved to death.
Bruising showed the orca was alive when it beached. It probably was separated from its mother just after birth and swept on to the beach where it was battered by waves. There was heavy bruising to its head and side from the stranding.
Dr Raverty, a veterinary pathologist who flew to Wellington specially for the dissection, said that on average, there was only one orca autopsy a year. "It's a very rare event for these animals to be cast on a beach. It's a great chance to gain an insight into the species."
Killer whales lived for up to 90 years. That meant they accumulated toxins from the ocean, Dr Raverty said. "We use them as an indicator species for environmental health."
Baby orca could gather pollutants from the womb and their mother's milk.
Samples will be sent to labs in Canada and the United States.
There are thought to be fewer than 200 orca living in New Zealand waters.
Ingrid Visser, from the Orca Research Trust, hoped DNA analysis would reveal which pod the baby came from.
"We will be trying to match it with other animals that have been genetically sampled."
The orca's skeleton will go into Te Papa's collection.
Killer whales hang out in family groups or pods.
Females give birth to their first calf from 11 to 16 years of age.
They give birth every five years during a 25-year reproductive life span.
Gestation is 15 to 18 months.
Calves are nursed for at least one year.
Females are known to live up to 80 or 90 years.
Males mature at about 21 years old and live to up 60 years.
Source: Conservation Department.
- © Fairfax NZ News
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