The Future Stings: jelly fish in a changing world

Being married to a food writer has exposed me to every type of food this planet has to offer. I’ve eaten larvae tacos, fish air bladders and thousand year old eggs whose packaging touts “now lead-free!”

Want to know how to cook a tarantula? Fish sperm? Tuna Jell-O? We’ve got a cookbook for that. While I return from conferences with my arms full of papers and books, my husband returns from his meetings with duffle bags full of almond candies, 10-pound wheels of cheese and black wine.

Once after returning from one of his trips with a pillow-case full of blue cheese I demanded that we immediately leave it outside the neighbor’s house, ring the doorbell and run away. Strangely, they took this as an act of friendship; I’d have seen it as warfare.

Overall I’d say I’m a pretty good sport. What is this life we live where we only eat Campbell’s soup?

There are a few items however, that I will not eat. I will not try blowfish — I saw that Simpsons episode as a kid, no thank you. I will not try nettle soup — you might argue it is totally safe, but I say you have never fallen into a pit of stinging nettle. And I will not try jellyfish — see the aforementioned stinging nettle argument.

Oh, but not eating jellyfish is actually a problem. As you might have heard, jellyfish (aka jellies, because dude, look at ’em – they are totally not fish!) are becoming far more common, making them a perfect food to start munching.

The question is: what is causing this new boom in jellies? Are warming waters making the environment more hospitable to these stinging floaters? Is ocean acidification negatively impacting their competitors giving them an unexpected advantage? Is an increase in hypoxic (aka low oxygen, aka low quality) environments, making jellies ideal competitors in certain regions?

It is actually hard to tell, because jellies have a really interesting, but sort of complex life cycle that exposes them to many different parts of the ocean, and the ocean itself is changing in all sorts of ways. What do I mean?

Well, the jelly’s life cycle is actually a little weird (there is this whole “releasing sperm from the mouth” and “freaky sci-fi colonies” sort of thing — check out this new age video demonstrating their life cycle or this hip hop one), but what you need to know is that there is a mobile part of the jelly life cycle (this is called the “medusa” — or what we know as a jellyfish, or jelly because like I said NOT A FISH) and there is a stationary part of the life cycle (called a polyp) when the animal is quite young and is attached to a surface on the ocean floor, creating a colony and chilling out.

As a floater you have certain things to worry about, like predators, competitors and water quality (snob). It turns out that people have done a nice job taking out the competitors and the predators (turtle soup anyone?), but also have reduced the water quality in some areas, which appears to negatively affect the predators and competitors, but not the jellies (1, 2). The jellies appear to be a little more hardy.

Ok, so what about when you are a stationary polyp stuck to the ocean floor? This has got to be a time when you are at high risk, right? Anything could come and disrupt you or eat you or poop on you, and whatcha gonna do little polyp? Move??? **Evil laugh**

Well, it turns out that people have been really hospitable about this as well. Because if you are a floating larvae looking for a place to set up house as a polyp, what are you going to look for? Perhaps a nice, sheltered inlet with lots of substrate to settle on? Hmmm…I wonder where you could find one of those? I don’t know…..maybe anywhere people dock boats or build fisheries or manage oysters? There aren’t a million of those globally….are there? Ahem (3).

Ok, so since this is a climate change blog, what about changes in ocean temperature? Can’t this affect jellies as well? Well, this is where it gets tricky because while it seems that temperature is a major driver of jelly success, this appears to be species specific (1). Meanwhile, we’ve got changes in water quality, and man-made ocean structures, and fewer predators and competitors….so like, lots of stuff going on for the jellies.

This may be bad news for swimmers like me who are already not crazy about hopping into the ocean as it is. But it is great news for people who love a good chewy, sesame-oiled jelly chopped on their plate. Because any way you slice it (yum!), it looks like in the future jellies are coming out on top.

Further Reading:
(1) Jellyfish and Ctenophore Blooms Coincide with Human Proliferations and Environmental Perturbations
(2) Effect of low dissolved oxygen concentrations on behavior and predation rates on red sea bream Pagrus major larvae by the jellyfish Aurelia aurita and by juvenile Spanish mackerel Scomberomorus niphonius
(3) Is global ocean sprawl a cause of jellyfish blooms?

Minda Berbeco has a PhD in Biology from Tufts University and is a science writer in the Bay area. She recognizes that she condensed an obscene amount of information into this blog post — jelly life cycles, eutrophication issues, climate change, stinging nettles….If you are interested in learning more on jellies she encourages you to start investigating the wealth of information available on the web, videos on YouTube and the newest issue of Hydrobiologia which is all about jellies (including jelly decomposition — yes people study jelly decomposition…you got a problem with that?).

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