The jellyfish population is continuously rising due to environmental disturbances particularly where there are polluted seas and where overfishing is rampant, a major concern raised by scientists.

According to researchers, overfishing and pollution could be hampering the population of other marine species with which jellyfish compete for food like planktons. From China, jellyfish are migrating to the Japanese seas to find more conducive habitat for their young called jellyfish polyps.

Back in 2000, there was a vast bloom of sea tomato jellyfish in Australia which could be viewed from space. It was an expanse of jellyfish that spread to over 1,000 miles.

Lisa-ann Gershwin, a jellyfish researcher from the Commonwealth Scientific and Industrial Research Organization, said that it was a memorable event because not all jellyfish blooms are that huge. She examined jellyfish over the past few decades revealing an increase in their populations over time especially in areas where environmental disturbances are prevalent, such as acid rain, overfishing, climate change and nutrient pollutions.

"What we see in the areas that are the most damaged from numerous different disturbances, we see these jellyfish bloom problems. The jellyfish seem to be the ones that are flourishing in this while everything else is suffering," Gershwin told LiveScience.

During the past several years, researches and reports have raised the issue of jellyfish populations rising. However, other scientists argued that this may be merely a coincidence. But most of them agreed that further studies on jellyfish populations are necessary.

Marine scientist Rob Condon said that it may take at least 10 more years of research to find a real conclusion about the issue.

Gershwin admits that to discover the link of increased populations of jellyfish and what causes them, more collaboration of "good, brilliant, innovative, creative scientists" is necessary.

According to the Smithsonian Ocean Portal, massive “jellyfish blooms” or “jellyfish outbreaks” can lead to series of problems. Having too many of them can interrupt fisheries, make for unpleasant swimming, or mess up the works of power plants that use seawater for cooling.