Are Jellyfish Taking Over the World's Oceans?

Written by Jaymi Heimbuch

The uptake in jellyfish numbers has been in the news a lot the last few years. Indeed just last year massive jellyfish blooms were the reason nuclear power plants in the UK had to shut down, as the little buggers clogged up water intakes used for cooling. Overfishing and climate change have been blamed, as predators of jellyfish are taken from the sea and changes in ocean temperatures and pH balance provide great environments for jellyfish to flourish. But a group of scientists say the drama revolving around “jellyfish taking over the ocean” could be a bunch of bunk.

PhysOrg reports that a study by experts from the Global Jellyfish Group, including Dr. Cathy Lucas, a marine biologist at the University of Southampton, say that the surges in jellyfish numbers are a completely normal part of the species’ history. Yes, we’re experiencing some significant blooms, but the notion that they’re going to take over the oceans in the future is not based on hard evidence, and it sparked interest in the group conducting a thorough study.

The study highlights the centrepiece of their research collaboration with NCEAS – the formation of a global database called the Jellyfish Database Initiative (JEDI) – a community-based database project that is being used in the global analysis and to test the worthiness of the current paradigm. The database consists of over 500,000 data points about global jellyfish populations collected from as early as 1750, and will be made as a future repository for datasets so that the issue of jellyfish blooms can be continually monitored in the future.

By analysing JEDI, the group will be able to assess key aspects behind the paradigm including whether current jellyfish blooms are caused by human-made actions or whether we are simply more aware of them due to their impact on human activities, such as over-harvesting of fish and increased tourism.

“This is the first time an undertaking of this size on the global scale has been attempted but it is important to know whether jellyfish blooms are human-induced or arise from natural circumstances,” says Dr. Robert H. Condon of Dauphin Island Sea Lab. “The more we know, the better we can manage oceanic ecosystems or respond accurately to future effects of climate change. The scientific data exists to answer this question, but it is fragmented in analysis”.

Science Daily reports that Dr. Condon and his colleagues think that the perception is based on a lack of information about past blooms, more attention being paid to current blooms, and of course “media fascination” with an uptake in blooms. However, they still acknowledge that changes in jellyfish populations do have serious impacts on other sealife and could indeed be impacted by human activity. But they want to gather significant scientific evidence before drawing hard conclusions about the future of our ocean.

This post was originally published by TreeHugger.

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Photo from Shayne Kaye via flickr

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Karen B.

1:37AM PST on Feb 12, 2012

Good article thanks

send a green star

Debbie L.

11:33AM PST on Feb 11, 2012

Thanks for the article.

Irene P.

12:45AM PST on Feb 8, 2012

Thanks for the atricle, Treehugger!

Laurie G.

7:39PM PST on Feb 7, 2012

The thing is, the most dangerous jellyfish are miniscule and highly venomous. I know that every animal has a place in the grand scheme of things, but I still hate jellyfish stings!

Cynthia B.

1:05PM PST on Feb 7, 2012

hmm humans disturb the balance of things to begin with

Brenda T.

10:48AM PST on Feb 7, 2012

I,d be delighted if they closed nuclear plants down permanently!

Nicholas L.

9:48PM PST on Feb 6, 2012

Unfortunately the natural balance of the oceanic ecosystems has been ruined by human actions. The species that control the population of jellyfish are being taken out of the equation, the jellyfish are much more resilient to the changes in the environment as well.

William K.

11:33AM PST on Feb 5, 2012

Although these population booms happen, I suspect that we will see that these are sustained, at least until the point that the oceans temperature and pH exceed the limits that the jellyfish themselves are able to tolerate.

Zana Z.

8:25AM PST on Feb 5, 2012

Having been a scuba diver for almost 40 years now, I've seen allot of jellyfish over the years....and been stung by a few too. Stings can be nasty.

But they can be cool to watch. Especially if you've got a great vantage point to be able to see light reflected through them. Really neat effect.

Anna A.

10:37AM PST on Feb 4, 2012

Stupid jellyfish. You hurt Dory.