It was hoped the number of breeding pairs at the tourism colony, at the base of the old quarry at Cape Wanbrow, would hit record highs this year.
But as the 2018 breeding season winds down, the number of breeding pairs for this season reached the same high it hit in 2014 and 2017 - 189.
Oamaru Blue Penguin Colony science and environmental manager Philippa Agnew said the season had started well and was shaping up to be a similar year to 2014, a benchmark for Oamaru's little penguins.
It was hoped there would be more birds at the Oamaru colony than ever before.
However, the breeding season stalled as severe weather hit at the end of November.
As the breeders began to produce their second clutch - little penguins can lay two sets of two eggs over the course of a breeding season - heavy rain and wind hit Oamaru's coast and the bullish breeding season suffered.
No new birds paired up to produce eggs, and the number of eggs produced also took a hit.
This year, 54 breeding pairs laid a second clutch and only seven of those pairs laid eggs in December, when the majority of eggs in a second clutch were laid.
In 2014, 70 pairs laid a second clutch, and 41 of those pairs produced eggs in December.
The success rate of the first clutch of eggs was identical in 2014 and 2018 - 78% of the eggs laid resulted in hatched chicks.
In 2014, 76% of eggs laid in the second clutch produced chicks. In 2018, that success rate dropped to 38%.
This year, 106 eggs were laid for the second clutch, from which just 40 chicks hatched.
Dr Agnew said as parents failed to find food in the turbid water off Oamaru's coast at the end of the year, nests were abandoned.
The colony's best breeding season remained 2014, she said, when 549 eggs were laid at the colony. This year, there were 498 eggs.
It remained a good breeding season, Dr Agnew said: 258 chicks fledging from the colony already and 37 chicks on nests still to fledge.
''It could've been better.''
Two birds had begun to moult at the colony and another two were also moulting at the Oamaru Creek Reserve colony across the harbour, Dr Agnew said.
As the breeding season ended, penguins would enter their most vulnerable phase as they replaced their feathers.
The moult was also highlighted this week by the Department of Conservation (Doc).
Doc Oamaru fieldbase ranger Tom Waterhouse urged dog owners, especially, to be aware of penguins, as the birds were particularly vulnerable from now to the end of April as they came ashore to moult.
Disturbance during this time could lead to increased stress ''and potentially permanent damage to new feathers'', he said.
''Blue [little penguins], yellow-eyed and crested species of penguin come ashore all along the coast of North Otago,'' he said.
''If you do see a yellow-eyed or crested penguin in a public place or somewhere out of the ordinary, give Doc a call so we can check as quickly as possible to see if it needs supporting through the moult or moving to a safer spot.
''Please don't pick up penguins you think need help.''
