Broome's quivering red sea

Flip Prior
The West

13 Sept. 2013

Thousands of big, quivering red jellyfish created a spectacle on Cable Beach yesterday.

Marine scientist James Brown, of Cygnet Bay, arrived with his sons about 6.15am to find the jellyfish, which had washed up overnight.

"They were very fresh, being pushed up by little swells that were rolling in," Mr Brown said.

Mr Brown, who set up the Kimberley Marine Research Institute at his Cygnet Bay pearl farm with fellow scientist Ali McCarthy, felt it important to record the phenomenon for further research.

He said globally, such blooms were of great interest to researchers, who were examining possible links between the blooms and effects of climate change.

"They're just trying to get as much evidence as possible - obviously, it's difficult to assess those types of things without people on the ground," he said.

"What we want to do now is find out how widespread they are - whether they stretch up the coast or not."

Australian Marine Stinger Advisory Service director, Dr Lisa-ann Gershwin - an international jellyfish expert - said the bloom was "impressive" but "worrisome".

Instantly recognising it as Crambione mastigophora, or sea tomato, she said such blooms may be symptomatic of damaged ecosystems and were increasingly frequent in WA coastal waters.

In 1977, the jellyfish caused an emergency closure of Karratha's power plant after big numbers blocked intake of seawater for its cooling systems.

Blooms were then rare until 2000, when the jellyfish appeared in "unbelievable numbers" , creating a "red band" from Rottnest all the way to up to Derby: "Probably the largest jellyfish bloom on earth."

Since then, the jellyfish have bloomed almost every year in localised areas, with significant numbers in Broome since 2006.

While their diet is unknown, close relatives hoover up big amounts of plankton such as copepods, larvae and fish eggs, causing problems in the ecosystem.

"They not only eat the fish eggs, but also the food that the larval fish would eat, and this double whammy can have a huge impact," Dr Gershwin said.

"When they die in large numbers, they create a huge pulse of goo that makes the bacteria switch to producing a disproportionally huge amount of carbon dioxide."

Worldwide, blooms had been attributed to warming seawaters, overfishing, coastal construction and pollution, she said: "Whether that is what's happening in WA, I don't know."

"I would love to see some really good research on this from somebody local who can really spend the time and effort looking into it … to find out what is going on with the species and what that means for Australian waters and particularly Australian fisheries in years to come.

"My educated guess is that we are going to see a lot more of this critter - and its impacts - as our ecosystems change."

'''THE FACTS
'

Species:'' Crambione mastigophora, or sea tomato

Origin: Originally named and classified in Malaysia

Appearance: A globular animal about the size, shape and colour as a large tomato. It is "quite unmistakable" and resembles no other jellyfish species

Movement: Little is known about its migratory patterns at this stage

Diet: Unknown, but relatives eat small plankton such as copepods, larvae and fish eggs.

Danger: It causes an annoying and painful but not life-threatening sting

Food: Some of its close relatives are harvested for food in Asia and Australia