The cute little penguins that call the St Kilda breakwater home have more than fluffy good looks – they also carry valuable information about the health of Port Phillip Bay.
Victoria University research has found that the St Kilda penguins have higher loads of arsenic, mercury and lead in their blood compared to their cousins on Phillip Island and the remote Notch Island colony in Bass Strait.
Annett Finger, a PhD candidate at VU’s Institute for Sustainability and Innovation, tested 300 little penguins as part of a three-year study to determine if they were useful in monitoring the health of the bay.
She and her colleagues collected small samples of blood, feathers and faeces for the study.
“St Kilda’s little penguins feed only within the bay so this was a unique opportunity to find out how contaminated their marine environment is,” she said.
Mercury levels in the penguin’s blood showed an increasing trend at St Kilda but decreased at Phillip Island between 2011 and 2013.
“While the source of the increased blood mercury is unknown, we do know that Port Phillip Bay went through major dredge works from 2008 to 2009,” she said.
Dredging may have disturbed polluted sediments – causing contaminated particles to enter the penguin’s food chain.
Ms Finger pointed to Environment Protection Authority records showing increased copper, chromium, lead and zinc levels in the water column during the dredge works.
Port Phillip Bay is a semi-enclosed ecosystem impacted by industrial run-offs, dredge works and commercial fishing.
“It is a potential contamination hotspot because it is quite shallow and closed off - historically polluted sediments are still there, they don't get flushed out,” Ms Finger said.
About 1000 little penguins – the same species that attract thousands of tourists to the famous Phillip Island penguin parade – live at the St Kilda breakwater.
Ms Finger said better understanding of the toxicology of the St Kilda’s little penguin population was important for the management and conservation of the species.
While the metal levels measured in the study were below established levels of concern, she hoped it would inform future environmental impact statements for developments in and around the bay.
The research, a collaboration between Victoria University, Phillip Island Nature Parks, the Institute for Marine and Antarctic Studies, RMIT University and the National Measurement Institute was published in the international journal Environmental Pollution.