The rats may have come from beech forest areas closer to Westport in the Buller Gorge.

Archived content: This media release was accurate on the date of publication. 


Results of toxicology testing of dead rats that washed up on North Beach near Westport recently show no presence of 1080.

Date:  20 November 2019

Maanaki Whenua Landcare Research tested eight dead rats and one weka. None of these animals had any residue of 1080 toxin. Two other rats were too decomposed to test.

Massey University School of Veterinary Science undertook post-mortem examinations of five of the dead rats but could not determine their cause of death. The weka was also examined with cause of death unknown.

DOC West Coast Operations Director Mark Davies says the test results confirm that the rats washed up on the beach are unlikely to have come from an area where 1080 had been used.

“We thought it was unlikely that rats had come from our aerial 1080 operation in Lewis Pass National Reserve near Maruia, 140 km upstream from Westport.

“We don’t know the source of the dead rats but it’s possible they came from beech forest areas closer to Westport in the Buller Gorge, affected by flood conditions.

“Rat numbers have exploded in beech forests due to heavy seeding and now seed is germinating, they are desperate for food, which can drive them into new areas and cause them to cross waterways,” says Mark Davies.

“Predator control is critical to protecting our most at-risk population of native wildlife as rats turn to eating native birds and bats and their young this spring and summer.” 

DOC sent ten rats for testing. Five went to Massey University for post-mortem and five to Maanaki Whenua Landcare Research for toxicology testing.

Following post-mortem, the five rats were also sent to test for 1080 although two were too decomposed to do this. The weka was also sent for post-mortem and 1080 testing.

It’s likely the marine animals which also washed up near Westport were victims of prolonged stormy weather at the time, which can have a negative impact on marine life.

About 680 dead rats were collected from North Beach over the weekend of 9-10 November. The rats were buried following advice from West Coast Regional Council.

Read the toxicology and pathology reports


For media enquiries contact:


Back to top