Jellyfish Are Turning Into Junk Food, Thanks To Climate Change

Jellyfish Are Turning Into Junk Food, Thanks To Climate Change

Don’t you know that marine creatures are starting to develop our habit of eating ‘junk food’ nowadays? Well, by eating junk food, we didn’t mean that they are developing legs to walk on the land and visit McDonalds or KFC. The ‘junk food’ in this story is jellyfish.

Yep, since there is a population bloom of jellyfish in the ocean, other marine creatures are treating them as abundant number of junk food. But why junk food? The answer is as simple as why most fast-foods nowadays are called so, because jellyfish contain only small amount of nutrition those creatures need.

This phenomenon is happening worldwide. But don’t you know that we are the ones responsible for forcing those marine creatures to develop this eating habit? Is it a good or bad thing for them and the ecosystem?

In this article, we will try to cover the new eating habit developed by worldwide marine creatures.

Population Bloom

Jellyfish by Hodgers
Jellyfish by Hodgers

If you often go to beaches in recent years, you might already notice that there are more jellyfish washed up on the beaches nowadays. The reason is no other than climate change, but in this case there is a slight difference.

Instead of killing them, climate change is actually nurturing them. Those jellyfish you found dead and washed up ashore were dead of natural cause. The reason why there are so many of them is because jellyfish population bloom these days.

Climate change, habitat destruction, trash, chemical waste, and overfishing are said to be the causes. But how can those bad things result in jellyfish population bloom?

Because of climate change and human activities, which result in some inconveniences in their native environment, they choose to migrate to other areas. Some of those new environments don’t have the right predator to control jellyfish population.

In this case, the only result available is population bloom, just like what happened in Australia when people first introduced rabbits there about two centuries ago. The problem is, overly crowded environment is another inconvenience for the jellyfish, which is another reason for them to move to another place and repeat this process all over again with larger number.

The Upside

jellyfish colors

Many of us are looking on jellyfish population bloom as a kind of disaster. Not only because jellyfish are invasive species in many areas of the ocean, but also because this creature’s main diet consist greatly of small fish larvae and eggs.

However, there is silver lining in this population bloom, according a study conducted by biologists at Queen’s University in Northern Ireland. In the study, researchers found that many marine creatures are adapting to jellyfish population bloom worldwide.

Jonathan Houghton, co-author of the study revealed that “It’s way, way more widespread in the food web than anyone ever would have thought”. There are many creatures that start to include jellyfish in their diets, as Houghton mentioned some of which are “from crabs, to benthic microbes, to ducks”.

Researchers predicted that the reason why this phenomenon happens is not only because there is huge number of jellyfish living in the ocean today. It also happens because jellyfish vary widely in size and composition all around the world.

In example, Portuguese man-of-war is a composite of different organisms living in symbiosis forming a bigger creature, while some other jellyfish species are almost microscopic. This way, not only bigger creatures are able to feast on them. Smaller fish and sea creatures are also able to enjoy the sea pudding.


junk food

As mentioned before, many marine animals including penguins, birds, and crabs, are starting to include jellyfish in their diets. The upside of this condition is that ocean now has more menu for those creatures. But still, it is not a good thing to celebrate.

Jellyfish is almost 100% water, which means that they contain so little nutrition for the consumers. This is why jellyfish belong to junk food for most marine creatures. Pure jellyfish diet is not going to work for all marine species.

In fact, you need to be their natural predator, or you will only eat more ‘junk food’. Thus, speaking of jellyfish’s predators, there is a must to mention sea turtles, their natural predator. Sea turtles, especially leatherback sea turtles, are said to be the most effective agent of control for jellyfish population because simply jellyfish is their main meal.

To constantly eat huge amount of jellyfish, “you need a specific metabolism, something like a slow leatherback (turtle),” as Richard Brodeur, fisheries biologist with the National Oceanic and Atmospheric Administration, said in an interview with National Geographic.

Leatherback sea turtles are the largest sea turtle on this planet nowadays. They can grow up to 2.7 meters long and weight up to 1000 lbs. Looking on their size, you should realize how much nutrition they need to consume.

The Biggest Predator

leatherback turtle (Wikimedia Commons)

Indeed, one adult leatherback sea turtle need to consume at least its bodyweight of jellyfish every day. For those large adult leatherback sea turtles, it means that they have to eat about 800 to 900 lbs of jellyfish every single day.

The problem is, leatherback sea turtles are currently critically endangered. There are many factors that affect this creature’s decline of population, but the one under the spotlight nowadays is plastic waste consumption.

Yes, to fulfill such a huge appetite, leatherback sea turtles are not picky. Every time they see something that similar to jellyfish, they will eat it. Whether it is a real jellyfish or a sheet of plastic bag, they will just consume it.

In conclusion, jellyfish population bloom is not always that bad, because it means that the ocean has more menu to provide for other creatures. However, too many is never too good. We still need steady population control to prevent bad things from happening.

Leatherback sea turtles are the biggest and most effective predator for jellyfish. But they are under the threat of extinction nowadays. So, if we let them go extinct from specific threats like littering the ocean with plastic, illegal poaching, or habitat destruction, it means that we are losing the most effective population control for ‘ocean’s junk food’.

Jellyfish are also known to eat small fish larvae and eggs, which may disturb the equilibrium of ocean ecosystem. Somewhat it means that the population bloom is a martyrdom to force other sea creatures eat more junk food. Will we let this happen?


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