The early arrival of penguins has ended in tragedy with eight penguins found dead on Middle Island.
After fox and dog paw prints were discovered on the island in early June two maremmas were sent to work to protect the penguins over low tide periods.
However it appears they were too late as subsequent searches of remote areas the island discovered the carcasses.
"We had reports penguins were arriving early at Phillip Island so members of the Middle Island Project Group decided to visit the island to see whether the same was happening in Warrnambool," Middle Island Project coordinator Dr Trish Corbett said.
"We found penguins, mostly male, had been arriving in small numbers.
Fox prints were also discovered on the beach fronting Stingray Bay and across other areas of the island.
Maremma's Eudy and Isola were taken on to the island on June 7 to guard any arriving penguins and remained on the island for three nights while the tide was low.
At the next low tide, Friday, June 21, Eudy and Mezzo were again placed on the island.
During this visit stray dog prints were identified on the beach and further investigation found a dead penguin.
A post-mortem examination revealed the penguin had been killed by a dog.
On June 22, the Middle Island Project team searched secluded areas of the island which cannot be seen from land or from the boardwalk.
A further seven penguin carcasses were found; one killed by a dog while the others were older and had been killed by a fox.
"We believe the penguin deaths by fox happened before June 6 but because they occurred in areas we couldn't easily see they weren't found until later," Dr Corbett said.
"We believe the death by a dog happened on June 20 just before the dogs were on the island.
In August 2017, the Warrnambool community was devastated after foxes got onto the island and killed about 70 penguins after the population had slowly recovered to more than 200.
Last October it was reported the penguin population was on the rise.
"Last year we estimated from the arrival numbers there were 25 breeding pairs or a total of 50 breeding penguins on Middle Island," Dr Corbett said.
"However we estimated the colony to be around 100 in total as some of the younger penguins wouldn't have been ready to come to the island to breed.
"We are not quite sure if the penguins found were apart of our colony or not as none of them were micro-chipped. They may have been penguins from other colonies coming to check out the island or they may have been penguins making their first trip over.
"Having talking to other scientists in the area the penguins in Portland have been coming in earlier and earlier to breed.
"We are still hopeful our penguin numbers can rise this year."
The effect of these recent penguin deaths won't be known until breeding begins in December.
These recent deaths come as a strong reminder to ensure no dogs are roaming around Middle Island.
"We do encourage dog owners to ensure their dogs are not wandering at night," Dr Corbett said.
Council also has a fox management program planned.
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