Giverny Forbes this week recorded her 101st encounter on an Otago beach with one of the naturally uncommon pinnipeds.
She observed a large male, nearly 3m in length, at Friendly Bay in Oamaru on Saturday.
On Tuesday, she went to record the presence of a sub-adult male at Aramoana.
In spite of a call from conservation groups, including the Department of Conservation, in August for public reports of the species, she had attended only six reports of the marine mammals this year.
A typical year, since she began studying the animals in Otago in 2018, included 10 to 15 encounters, Miss Forbes said.
Usually, reports started to decrease in November, but the reports over the past week made her hopeful this year the peak in sightings might simply happen later.
"It’s definitely something that’s piquing my interest. If they’re not turning up, then ... well, what’s happening?
"It could be an indicator of something bigger going on in our oceans, because leopard seals feed on almost anything.
"Because they might be migrating around the Southern Ocean, it could be reflecting something going on in the Southern Ocean."
If decreased sightings continued next year, then her interest might turn to worry.
"There’s so little known about them, every opportunity to observe them is an opportunity to learn something from them."
Miss Forbes was at present collecting scat samples to send to a researcher at the University of Canterbury to learn more about the animal’s diet.
It was "pretty obvious" birds, including shags, seagulls and, probably, little penguins, were on the menu as feathers were abundant, she said.
Ghost sharks were also known prey.
While the sex of the animals appearing on Otago beaches was split evenly between males and females, the leopard seals at local beaches were most often sub-adults, measuring 2m or 2.5m, not over 2.7m, the size of an adult.
The "big mystery" with leopard seals remained "what are they doing in New Zealand?"
Until 2019, the species was considered a vagrant in New Zealand waters, meaning there were theoretically only 15 individuals in New Zealand in any given year.
Increased sightings contributed to the species that year being granted resident status by the Department of Conservation, which changed its conservation status to naturally uncommon, indicating fewer than 250 individuals were understood to be in New Zealand.
