Turbid sediment-laden stormwater threat to penguins

Otago's severe spring storms could spell an end to an otherwise likely record-breaking breeding season for Oamaru’s little penguins.

The brown, turbid water beyond Oamaru Harbour could make foraging "really challenging" for breeders feeding chicks, Oamaru Blue Penguin Colony research scientist Dr Philippa Agnew said. And with climate scientists predicting more frequent and more intense storm events, heavy rain and wind, and waves higher than 2m over several days, causing extensive patches of turbidity regularly — the storms could be "a deal-breaker" for the birds.

"Potentially, going forward, these events are going to be a bit of a deal-breaker for the penguins — possibly," Dr Agnew said.

"And with rain and sedimentation, and run-off — go and plant some trees, you know.

"Sedimentation is such a massive issue for the oceans ... we are seeing the results of that right here."

Heavy rain and wind  last week brought a slight decrease in the number of birds coming ashore at night, she said. At the tourist colony at the Cape an average of more than 200 little penguins came ashore each night all through October and through most of November.

But since the storm that number  dropped to 100 or 150.

"In the wintertime, what happens, this kind of storm ... if it lasts more than five or six days, that brown [water] that you can see, it’s brown all the way out to the horizon," Dr Agnew said.

"And we don’t ever see it like this in the summer, generally."

In 2015, a major winter storm had a significant impact on Oamaru little penguins — only 60% of the adult birds survived the year rather than the 86% average.

The breeding season for Oamaru’s little penguins began early this year and last week about halfway through the season between the two colonies managed by staff at the Oamaru Blue Penguin Colony, 499 chicks had hatched — 743 eggs were laid at the  colonies.

At the tourism colony at Cape Wanbrow, 90 chicks had fledged and 57 had fledged from the Oamaru Creek colony — 347 chicks had been microchipped at Oamaru Harbour.

So far, 32 pairs at the Cape colony had produced a second clutch as had 20 pairs at the creek.


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