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Tuesday, December 25, 2012
Thursday, December 13, 2012
Southern Australia penguin population falls dramatically
Updated
A census of little penguins on South Australia's Kangaroo Island
has revealed the number of breeding adult birds has fallen by about a
quarter in the past year. Debate is raging about what's behind the
population drop, with some locals blaming the growing number of New
Zealand fur seals.
Source: The World Today
EMILY BOURKE: A census of little penguins on South
Australia's Kangaroo Island has revealed some disturbing figures: the
number of breeding adult birds has fallen by about a quarter in the past
year.
Debate is raging about what's behind the population drop, with some locals blaming the growing number of New Zealand fur seals.
Clare Hesketh reports.
CLARE HESKETH: The latest count shows that in the past 12 months, penguin numbers have plunged from just over 1,300 last year to about 960 this year.
In Penneshaw, the colony has almost halved.
Counts have been done at Kingscote since 2006 and numbers there are estimated to have dropped by more than a third in the six year period.
Danny Brock is a marine scientist with the South Australian Environment Department.
He says the figures are concerning, but not surprising.
DANNY BROCK: We have been losing mainland penguin colonies over the last 20 to 30 years across southern Australia, and now also some of the offshore islands have been experiencing decline.
CLARE HESKETH: Mr Brock says commercial fishing, coastal development and climate change have put pressure on the penguins.
It's thought predators such as cats and New Zealand fur seals are also hitting numbers.
Ikuko Tomo from the South Australian Museum has been studying dead penguins found onshore on Kangaroo Island for the past two and a half years.
She's received about 100 specimens in that time.
IKUKO TOMO: Primary cause of the death is trauma but some animals have got some infected bug parasite. But most of the animals more look like possibly predation, but some of them are killed by the traffic accident.
CLARE HESKETH: The Kingscote Penguin Centre has been vocal in blaming rising New Zealand fur seal numbers for much of the penguin decline.
At last count, there were just over 36,000 of the seals on the island.
Danny Brock says that's expected to increase by about 10 per cent a year for the next decade, partly due to the species' recovery from the end of commercial sealing in the late 1800s.
But he rejects the Penguin Centre's claims.
DANNY BROCK: They are a pressure on penguin populations, but can we say how much they're doing it and are they solely responsible for the declines, no we're not in a position to say that yet.
CLARE HESKETH: The local Liberal MP, Michael Pengilly says it would be a major blow to the industry if the attraction was no longer there.
MICHAEL PENGILLY: The numbers of penguins at Penneshaw have virtually disappeared and at Kingscote, the numbers are declining. So clearly international visitors in particular who like to look at the penguins and their activities are struggling to find them.
CLARE HESKETH: But Danny Brock is hopeful that little penguin numbers on the island will eventually bounce back.
DANNY BROCK: I mean if we implement some of the management issues we need to, then definitely. I mean Phillip Island is the classic example of penguin numbers recovering when a number of coastal issues have been dealt with. So I guess it will be watch this space.
CLARE HESKETH: Any future island-wide counts are dependent on more community funding or financial help from the State Government.
EMILY BOURKE: Clare Hesketh with that report.
source
Debate is raging about what's behind the population drop, with some locals blaming the growing number of New Zealand fur seals.
Clare Hesketh reports.
CLARE HESKETH: The latest count shows that in the past 12 months, penguin numbers have plunged from just over 1,300 last year to about 960 this year.
In Penneshaw, the colony has almost halved.
Counts have been done at Kingscote since 2006 and numbers there are estimated to have dropped by more than a third in the six year period.
Danny Brock is a marine scientist with the South Australian Environment Department.
He says the figures are concerning, but not surprising.
DANNY BROCK: We have been losing mainland penguin colonies over the last 20 to 30 years across southern Australia, and now also some of the offshore islands have been experiencing decline.
CLARE HESKETH: Mr Brock says commercial fishing, coastal development and climate change have put pressure on the penguins.
It's thought predators such as cats and New Zealand fur seals are also hitting numbers.
Ikuko Tomo from the South Australian Museum has been studying dead penguins found onshore on Kangaroo Island for the past two and a half years.
She's received about 100 specimens in that time.
IKUKO TOMO: Primary cause of the death is trauma but some animals have got some infected bug parasite. But most of the animals more look like possibly predation, but some of them are killed by the traffic accident.
CLARE HESKETH: The Kingscote Penguin Centre has been vocal in blaming rising New Zealand fur seal numbers for much of the penguin decline.
At last count, there were just over 36,000 of the seals on the island.
Danny Brock says that's expected to increase by about 10 per cent a year for the next decade, partly due to the species' recovery from the end of commercial sealing in the late 1800s.
But he rejects the Penguin Centre's claims.
DANNY BROCK: They are a pressure on penguin populations, but can we say how much they're doing it and are they solely responsible for the declines, no we're not in a position to say that yet.
CLARE HESKETH: The local Liberal MP, Michael Pengilly says it would be a major blow to the industry if the attraction was no longer there.
MICHAEL PENGILLY: The numbers of penguins at Penneshaw have virtually disappeared and at Kingscote, the numbers are declining. So clearly international visitors in particular who like to look at the penguins and their activities are struggling to find them.
CLARE HESKETH: But Danny Brock is hopeful that little penguin numbers on the island will eventually bounce back.
DANNY BROCK: I mean if we implement some of the management issues we need to, then definitely. I mean Phillip Island is the classic example of penguin numbers recovering when a number of coastal issues have been dealt with. So I guess it will be watch this space.
CLARE HESKETH: Any future island-wide counts are dependent on more community funding or financial help from the State Government.
EMILY BOURKE: Clare Hesketh with that report.
source
Sunday, December 2, 2012
Little penguin colony viability impacted by Leeuwin current change
Sunday, 02 December 2012
Dr
Cannell notes that one of the most important findings of the study was
of the correlation between higher sea surface temperatures around April
and reduced breeding performance. Image: WhatsallthisthenA RECENT study has found links between environmental conditions and breeding performance in a colony of Little Penguins (Eudyptula minor) near Rockingham.Researchers have correlated the strength of the Leeuwin Current and timing of breeding of the colony on Penguin Island, as well as a link between sea surface temperature and breeding success.
The correlation is linked to a decrease in many species of fish that Little Penguins feed on.
Murdoch University Research Associate Dr Belinda Cannell says, “When there’s a strong Leeuwin Current in the summer prior to breeding, the [penguin’s] laying will end up finishing later.”
Delayed laying is dangerous for the health of the colony.
“The later they lay in the season, the less likely they are to successfully raise those chicks because it’s moving into the times they have to moult,” Dr Cannell explains.
Little Penguins are unable to hunt for food during moulting as they are without waterproof feathers.
Later laying times also make for increased mortality rates due to higher temperatures.
“It also means they’re raising chicks when the terrestrial temperatures are getting very hot, so there’s an increased chance of chicks dying,” she says.
Dr Cannell notes that one of the most important findings of the study was of the correlation between higher sea surface temperatures around April and reduced breeding performance.
“The chicks were lighter when they fledged; there were fewer chicks per pair, fewer eggs actually hatched and fewer eggs resulting in successful fledglings”, she says.
A correlation was also found between breeding success and environmental conditions in the winter months of the previous year.
“When the sea surface temperature and the Leeuwin Current were stronger in the year prior to breeding, the laying of the eggs will be earlier in the year.
“The earlier they lay, the more likely they are to lay two clutches, the healthier the chicks are and the more likely they are to survive.”
The analysis uses data from between 1986 and 2008, with various measures of breeding performance being compared to oceanographic data to develop statistical models. These models are then tested against new data from 2009 to 2011.
Dr Cannell says the study is valuable as one of few long-term data sets nationwide for marine fauna, describing the penguins as “ideal sentinels of climate change.”
She says the colony of Little Penguins is an excellent way of evaluating changes to the environmental system as a whole.
source
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