New jellyfish spotted

By Georgina Scambler

Eagle-eyed Docklanders may have noticed a different species of jellyfish lurking in the water around Docklands.

Larger, more colourful and with longer tentacles than the blue blubbers that have previously been abundant in the harbour, the new jellyfish is Cyanea annaskala, or lion’s mane.

Melbourne Museum jellyfish expert Joanna Browne said the lion’s mane was more likely to sting than the blue blubber, but was not extremely dangerous.

“They’re not like irukandji or box jellies that you find up north, they’re not likely to kill you,” Ms Browne said.

According to Ms Browne, different species of jellyfish often vary in abundance over time, with Lion’s Mane tending to be more dominant in the winter months, and blue blubbers between September and March.

Ms Browne said drought conditions may have made blue blubbers more dominant in recent years.

“Now that we’ve had more rainfall and differing conditions in the bay, you might find that Cyanea becomes more dominant for a while,” she said.

Recent data published by the University of Western Australia suggests that man-made structures like harbours and shipping facilities provide ideal habitats for jellyfish polyps to grow, thus explaining apparent increases in jellyfish blooms.

Ms Browne said this was likely to be a bigger issue in “massively overdeveloped” places such as China than in Melbourne.

“Nobody really knows exactly what triggers different species,” Ms Browne said.

“It seems that different salinity, more water coming down the Yarra, and things like nutrient run-off affecting food for the jellies … give better conditions for different polyps to grow.”

Ms Browne said a great resource for anyone interested to learn more about what’s in the bay, including jellyfish, was the Port Phillip Bay Taxonomic Toolkit, to which she had contributed a section on jellyfish.

Read about the lion’s mane jellyfish at http://www.portphillipmarinelife.net.au/species/7761