Plan to release RHD may cost $50,000

The Otago Regional Council seems likely to spend up to $50,000 in unbudgeted funding to co-ordinate the release of a Korean strain of the rabbit haemorrhagic disease virus this year.

Scott MacLean.
Scott MacLean

In a report prepared for a meeting of the council's regulatory committee today, council environmental monitoring and operations director Scott MacLean recommended the funding, from reserves, be approved.

This would enable the ''co-ordinated release'' of the Korean strain of the rabbit haemorrhagic disease virus (RHDV-1 K5) at ''strategic locations'' throughout Otago''.

The council is a member of the New Zealand Rabbit Co-ordination Group, whose collaborative membership includes representatives from regional and district councils, the Department of Conservation, Ministry for Primary Industries and Federated Farmers.

The group is seeking statutory approvals to register, import and release the Korean strain, which is a variant of RHDV-1, the form of RHD virus which is already in the country.

If approvals were obtained as expected, the ''favoured release window'' was this autumn, Mr MacLean said in his report.

The release had to be ''strategic and well-co-ordinated'' to give the best chance for the virus to work and to start to spread naturally.

In Otago, it was thought virus doses should be released no more than 5km apart, with areas of high rabbit numbers the priority for release.

This would be predominantly the Upper Clutha from Roxburgh through to Queenstown and Wanaka, including the Tarras area, the Strath Taieri area, Maniototo, and parts of Coastal Otago, including Balclutha, the Otago Peninsula and Shag Point/Moeraki areas, Mr MacLean wrote.

It was important the ORC had control over the release, with respect to location, timing, management and monitoring.

''This will ensure carrot bait treated with the high-quality, commercially prepared product will be placed in the optimum locations.''

There would be logistical ''challenges'' to distribute the treated bait across the region simultaneously, and ''in-kind support from landowners'' would be needed to carry out this function according to strict protocols.

To ensure full control, increase the likelihood of success and ''maximise environmental benefits'', it was proposed the council cover the cost of each dose and associated bait preparation and initial distribution as ''an investment back into the community's rabbit control efforts''.

This was unbudgeted and was likely to cost up to $50,000, including the cost of the virus, two pre-feed carrot applications and one treated carrot application, with landowners providing the labour to distribute the baits.

Only 10kg of carrot was required at each site for each feed so the in-kind distribution efforts would be ''modest''.

The Korean viral strain was a ''potentially significant biological control tool'' for pest rabbits, and it was expected there would be ''improved knockdown''- ranging from 0-40% - in areas where the current virus strain was less effective.

The improved ''knockdown'' rate would depend on the location of the rabbit population and the number of susceptible animals within it.

A limited number of doses would be imported, and the council had asked for 100 doses, which would be a ''significant proportion'' of the overall doses available, Mr MacLean said in his report.

john.gibb@odt.co.nz'

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