Large numbers of jellyfish have also appeared on beaches and coastal waters off Cairns and the Gold Coast in recent weeks. 

Jellyfish populations go through large fluctuations but recent outbreaks have beena attributed to climate change and overfishing of natural jellyfish predators. 

Lisa-Ann Gershwin from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) said that large jellyfish blooms were a sign something was wrong with the ocean. 

“Jellyfish blooms are a visible indicator that something is out of balance in the ocean...maybe warming water, or too much nutrients, or not enough oxygen, or a reduction in predators or competitors,” she said. 

"As the ecosystem declines, there are winners and losers and jellyfish more often than not are those winners."

Blooms of both venomous and non-venomous species of jellyfish can cause big problems. 

Venomous species such as box jellyfish and irukandji can inflict fatal stings, especially in large numbers, while huge blooms of non-lethal jellyfish can be sucked into intakes and clog underwater machinery.