Two Thirds of Maui’s dolphin may get fins bolted

2/3 of critically endangered Maui’s dolphin may get fins bolted

An assessment by the Department of Conservation’s (DoC) Science and Research Division indicates that up to two thirds of critically endangered Maui’s dolphin could have tags bolted to their fins following a controversial trial on threatened Hector’s dolphin in Akaroa Harbour.

Yesterday, DoC announced it had granted a permit for an experiment that will involve bolting satellite transmitter tags onto Hector’s dolphin in Akaroa Harbour. If successful, the even more critically endangered Maui’s dolphins will also have satellite tags bolted to their fins.

The Auckland Conservancy of DoC plans to find out more information about the range of the critically endangered Maui’s dolphins by using the satellite tags.

“A report by marine mammal experts from DoC’s own Science and Research division is critical of the trial and warns that the Auckland Conservancy may need to tag a third of the critically endangered Maui’s dolphin to find out the distribution information that they say they need in any one season,” said Forest and Bird Conservation Manager Kevin Hackwell.

However, DoC intends to determine the summer and winter distributions of the dolphin. “This will require two rounds of tagging, once in winter and once in summer. Two out of three Maui’s dolphin could have tags bolted to their fins.

This is no way to carry out research on the world’s rarest marine dolphin,” he said. “Aerial surveys have proved to be an effective and safe alternative for determining the distribution of Maui’s dolphin. A summer survey was completed only a couple of weeks ago and appears to have been very successful,” he said.

Note Relevant quote from the report:

The lack of development and testing of tags on Hector’s or Maui’s dolphins constitutes an inherent risk with this technique on a critically endangered species. A small sample will not allow for the reliable estimation of distribution of the whole species, and any statistically robust tagging project would be extremely expensive (in excess of $500,000) and require the tagging of [a] high proportion of the total estimated population (e.g. a sample of 25 Maui’s dolphins tagged could represent 33% of the entire sub-species). The tradeoffs for this are that while something may be learnt about a sizable portion of the population, any risk associated with the technique is also applied to the same proportion. A decision analysis framework for the tagging of Maui’s dolphins by the IUCN Small Cetaceans Specialist Group produced a net negative result indicating that tagging would yield extremely small benefits to the species when weighed against the high risks (Johnston and Read 2003).

From pg 35 of Childerhouse and West’s report:

Scientific Tools to Assist the Management of Maui’s Dolphin - an evaluation of scientific tools to explore the adequacy of current protection measures and an assessment of disease and pollutants. WGNCR-48563. January 2004

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