Research Technique May Help Save Maui's Dolphin
FOR IMMEDIATE USE
23 February 2004
NEW RESEARCH TECHNIQUE MAY HELP SAVE MAUI'S DOLPHINS
The Department of Conservation is to trial satellite-tracking, a technique never before used on New Zealand dolphins, to help save the critically endangered Maui's dolphin from extinction.
Satellite-linked transmitters will be trialled on three South Island Hector's dolphins off Banks Peninsula to assess the technique's suitability for the closely-related Maui's dolphin, which lives off the North Island west coast.
Department of Conservation Auckland conservator Rob McCallum said this research method had the potential to reveal where the dolphins range and how far they travel offshore - information urgently needed to protect Maui's dolphins from fishing related threats.
"Our efforts to save New Zealand's rarest dolphin are being hampered by what we don't know about them. We need to find out if Maui's dolphins move outside the current set netting closed area. If so, we need solid evidence to show this and to determine how much of their time they spend in different areas."
"Satellite tracking shows great promise in helping to answer this question. It can give real-time information about where dolphins go, day and night, in all weather conditions and in a relatively short time frame."
Mr McCallum said other research methods currently in use such as aerial survey, acoustic devices and genetic studies, contributed to the picture of dolphin distribution but did not give all the information needed.
"Surveys are good for studying dolphins where you expect to find them, which runs the risk of giving a selective and incorrect picture of their total movements."
Satellite tracking has been used successfully overseas on other small dolphins and porpoises where it has sometimes revealed surprising results. Harbour porpoises in the Bay of Fundy, Canada, once thought to rarely leave their home coves, were shown to travel extensively out into the Atlantic Ocean, for example.
"Overseas researchers are questioning why New Zealand isn't using this technique to find out what is really going on with Maui's dolphin," said Mr McCallum.
Recently Maui's dolphins have been seen off New Plymouth, up to 100 kilometres south of the closed set netting area, but an aerial survey failed to spot the dolphins.
"With less than 150 Maui's dolphins left, we need to consider all means available to find out what we need to know to save this dolphin. We can't afford to wait," he said.
The custom-made satellite tags for the trial are one of the smallest and most streamlined marine mammal transmitters ever built. The tags are the length of two match boxes laid end-to-end and weigh about 50 grams (the weight of three 50 cent pieces).
Mr McCallum said the technique was not without risks, which is why it was being trialled first on the more numerous Hector's dolphins. The three month trial will start shortly.
A team of international and New Zealand experts including marine mammal scientists and a specialist veterinarian will conduct the trial.
The trial has been approved by Massey University's animal ethics committee and will be subject to strict conditions under a marine mammal research permit, which includes a comprehensive risk assessment.
The department has consulted with interested groups and has the full backing of Ngai Tahu to carry out the trial on the Banks Peninsula dolphins.
* Maui's dolphin is found only along part of the west coast of the North Island and is listed by the IUCN (The World Conservation Union) as "critically endangered".
* The dolphin used to be known as North Island Hector's dolphin but research has shown the North and South Island dolphins are separate sub-species.
* Fisheries regulations ban set netting within four nautical miles of the North Island west coast from Maunganui Bluff (north of Dargaville) to Pariokariwa Point (north of New Plymouth). Set nets are also prohibited in the Manukau Harbour entrance.