Poison drops on Molesworth Station suspended after 1080 drop kills dozens of red deer

Poison drops on New Zealand's largest farm have been suspended after scores of red deer died in a 1080 operation targeting possum.

Deer hunters self-funded an aerial survey of the historic 180,000-hectare Molesworth Station in the South Island after a 1080 (monosodium fluoroacetate) drop in October last year by TBFree NZ was feared to have unintentionally wiped out as many as 345 red deer.

The final number of carcasses spotted lying on the vast farmland is yet to be publicly-released, with the Marlborough branch of the New Zealand Deerstalkers Association (NZDA) saying its scientists are still writing their comprehensive report.

Meanwhile, Ospri, the government-backed company, formerly the Animal Health Board, which is fighting to eradicate tuberculosis (TB), has deferred any further drops on Molesworth Station "until at least next year".

"The deferment was decided after the initial possum control operation [in] 2017 killed more deer than expected, meaning future operations may need to use deer repellent over a wide area," an Ospri spokesman told the Herald.

Ospri say they are now undertaking further research and testing into alternative repellents, which could also prove "significantly more cost effective".

NZDA Marlborough branch committee member Wayne Smith welcomed the move.

"We are pleased that further 1080 drops have been deferred," he said.

"Hopefully the new deer repellent options will be effective as well and in future we see a large reduction in by-kill from these operations."

The Department of Conservation (DoC), which owns the station and leases it to Landcorp Farming Ltd, gives Ospri permission to run pest control operations on public conservation land.

Ospri's TBfree nine-year programme is designed to eradicate bovine tuberculosis from Molesworth, which has a long history with TB infection in its cattle herd and wildlife, dating back to the early 1960s.

Eight helicopters using GPS dropped toxic bait at 2kg/ha on a 61,200ha area late last October after "significant public and community engagement".

"The justification for possum control was compelling and also carried significant conservation benefits," an Ospri spokesman said at the time.

"Ospri recognises that there is always a risk of deer by-kill as a result of 1080 application for pest control and is committed to working with hunting groups to minimise the impacts on these populations through targeted use of deer repellent."

DOC South Marlborough Operations Manager Phil Bradfield denied claims that local hunters weren't allowed to go shoot deer before the 1080 drop.

"Recreational deer hunting is allowed on Molesworth with a permit and hunters were on Molesworth leading right up to the operation," he said.

Experienced helicopter pilot Bill Hales, who has 40 years' experience as a wild animal recovery operator (WARO), was disappointed by a "crying shame of a wasted resource".

"Why not let us guys in there for three months before you have a poison drop and harvest the product? Why waste the resource?" he said.

Animal rights groups are opposed to the use of 1080.

Ospri said that until an alternative to 1080 is found, it remains "the best tool in the toolbox for controlling the introduced predators that transmit TB between wildlife and livestock".