Picton EcoWorld staff have accused nearby boat owners of allowing their cats to attack little blue penguins and ducklings at the aquarium, but the boat owners deny the claims.
EcoWorld manager John Reuhman contacted the Marlborough SPCA and other authorities after witnessing, he says, one of Picton resident Kim Delisser's cats mauling a duckling near the aquarium as she watched on the Picton foreshore on November 16.
Ms Delisser denies the cat killed a duckling as she paused while walking the cat on a lead.
A Marlborough SPCA staff member did not find anything wrong with the way Ms Delisser cared for her tabby cats, Monty and Nelson.
Mr Reuhman said boat owners' cats were a controllable threat to little blue penguins and ducklings, which were a common sight on the foreshore at this time of year.
A non-lethal trap in the aquarium's outdoor penguin rehabilitation area, between the building and the harbour, caught 11 cats over the past two years. Six of them were domestic from nearby boat owners and a business, Mr Reuhman said.
"Cats are one of the biggest killers of wildlife in New Zealand, and they can't be let loose to hunt as they please, especially at night.
"We had a penguin savaged by a cat in March. It reached through the cage and clawed its neck.
"We hose them down and release them, but within an hour they can be back out hunting again."
Ms Delisser said her cats were desexed, collared, microchipped and kept inside at night.
"I understand where he's coming from. I'm a pet lover myself from rat to budgie, but I'm not going to stand by if he's going to threaten to do something to our cats.
"We've been inspected by the SPCA to make sure the cats are well cared for."
Her partner, Steve Liverton, said Mr Reuhman's accusations were unfounded.
"We say the penguins are going missing because of the rats - who knows how many eggs they eat - and the cats kill the rats.
"The majority of ducklings are caught by the shags - it's not our cats."
One cat owner, who had lived on a boat near the aquarium for 10 years but wished to remain anonymous, said his 9-year-old ginger tabby cat, Billy, only caught the odd rat.
"He goes out for an hour or so each night and then he comes back."
Billy wore a collar with his owner's contact details and was desexed.
Marlborough SPCA inspector Christina Costello said the best thing cat owners could do was make sure their pets were desexed, collared, microchipped and kept inside at night.
"We don't want them in areas where they can be a nuisance, so if they're going out then perhaps put them on a lead."
She said Mr Reuhman could sprinkle water on them if they came near the aquarium to deter them.
"After that, it would be nice to think he could return them to their owners."
- The Marlborough Express