She said one duck remained and was still very mobile despite being sick, with attempts to retrieve it unsuccessful, including a swim in the lake by Ms Kemp.
Preliminary necropsies at Wellington SPCA showed signs of rapid fat depletion in the ducks, confirmed by necropsies performed by vets at Massey University.
"All the ducks were found to be very underweight.
"Pekin ducks are not found in the wild in New Zealand and are instead often kept as pets.
"It's likely this group were raised in captivity, then deserted and left to their own defences."
She said unfortunately, they were not equipped to survive in the wild.
"Someone's assumption that as a duck, they'd be fine out in the wild has proved fatal for most of these ducks."
Passers-by, who reported the group of dead ducks to authorities, said the ducks appeared on the lagoon around one month ago.
Locals had questioned whether the ducks were poisoned and if the quality of water in the lagoons was suspect.
"None of the other numerous fowl on the lake and in the surrounding areas were affected.
"No other abnormalities were found, though we are still waiting on biopsy and toxicology reports."
Council tested the water and said the levels were all within normal range.
Kemp said Pekins are very social and friendly birds and make great pets.
"It's really disappointing that whoever left them there didn't contact the SPCA first, as we would most likely have found them loving homes.
"Instead, they've been left to starve in the middle of winter."
According to New Zealand's Animal Welfare Act 1999, under section 14 (2), deserting an animal without making provisions for its physical, health and behavioural needs is an offence that carries a penalty of up to $50,000 and/or up to a year's imprisonment.
If anybody has any information to help with the investigation, contact 0800 INSPECTOR.
