Attack of the blue blubber jellies

Attack of the blue blubber jellies

By Callie Morgan

Experts say high rainfall levels or this month’s warm and windy weather could explain the recent jellyfish bloom in Docklands.

Docklands’ residents may have noticed thousands of the eerie creatures drifting through the water around NewQuay and wondered what had caused their sudden increase in numbers.

Professor Robert Day from the Melbourne University’s department of zoology said there were a number of elements involved in explaining the jellyfish bloom.

“Jellyfish blooms are not well understood because there are lots of factors that are involved,” Professor Day said. “Currents and winds are often involved in concentrating them together.”

Joanna Browne from Melbourne University said she had been studying jellies in the bay since 2008 and suggested recent rainfall could also explain their high numbers.

“Rainfall influences the salinity and temperature of the water, which could make the environment more inhabitable for the jellies,” Ms Browne said.

“Food sources and an increase in artificial structures in the water also affect jellyfish numbers,” Ms Browne said.

Ms Browne said the jellyfish species that could be seen in the harbour were called catostylus mosaicus but were more commonly referred to as blue blubbers.

While several studies of jellyfish numbers have been conducted in recent years, Ms Browne said results regarding any significant increase in numbers were inconclusive.

“There is a lot of literature about jellyfish blooms and some recent controversy about whether they are increasing or not,” Ms Browne said.

“Since I’ve been studying jellyfish, the only species I’ve seen in bloom proportions is catostylus mosaicus.”

Ms Browne said Docklanders wouldn’t need to worry about the thousands of jellies floating in the harbour as a human death by a blue blubber had never been recorded.

“Most people only get a mild stinging sensation when they come into contact with these jellies,” Ms Browne said.

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