Ranger crew encounters jellyfish swarm

Overfishing, pollution contribute to exponential rise

Posted by Andrew Sharpless (Guest Contributor) at 4:18 PM on 11 Jul 2007

Read more about: fishing | oceans | wildlife | biodiversity

Oceana divers documenting the state of ecological communities in Cabrera Marine Park along the Mediterranean Coast encountered swarms of jellyfish, with numbers in the thousands, 30 miles south of the area.

On a seamount some 130 meters from the surface, Oceana's unmanned submarine robot revealed especially high concentrations of these jellies that have wreaked havoc along the Mediterranean in years past. Oceana is working to have the area added to the national park.

High concentrations of jellyfish are not a local problem. The same factors that allow jellyfish to "overflourish" in many parts of the world are at play here: Essentially humans are creating a jellyfish wonderland by overfishing and polluting our oceans.

Warmer water temperatures due to climate change and an elevated presence of mineral nutrients thanks to urban and agricultural runoff create pristine conditions for jellyfish to multiply. By fishing out larger species, fewer predators are around to counterbalance the thriving jelly population.

The end result is an ecosystem out of whack, and only simultaneously addressing all sides of the problem will allow natural factors to take hold and control jellyfish populations.

For story: Ranger crew encounters jellyfish swarm
8 Comments | Post a Comment

here's something interesting

jellyfish mucus perfect for cosmetics

by naturescene at 4:35 PM on 11 Jul 2007

How about Moon Jellyfish?

... an Oriental delicacy.

But my BS-O-Meter went off the scale on this thread. Sure, the Med may be having an issue - I've seen parts of the US Northeast, Gulf, and West Coast infested with jellyfish at times but hmmm ... seems like back in the 1970's it was much worse. So without any real scientific research some folks in Spain say "Dios, it's the end of the world!" and Grist picks up on the storyline because it seemed cool.

Anyway, I've been fishing and surfing down here in the Gulf of Mexico all year and there are NO JELLYFISH. There should be one about every 25 feet washed up on the beach. Go figure. Sam

Onward through the fog

by Sam Wells at 5:17 PM on 11 Jul 2007

The Gulf of Mexico is not the scene

The infestation was in European waters not the Gulf.

by azelb at 7:17 AM on 12 Jul 2007
[ Parent ]

jellyfish

I sailed through Monterey Bay a couple years ago, and the jellyfish swarms, species after species, went on for miles and miles.

I suppose that is the classic case that the herring/anchovy fishery gave them their new niche?

Is there an ichthiologist in the house?

by odograph at 8:02 AM on 12 Jul 2007

Nature, you are so mysterious

While I can't speak to this jellyfish concentration (cause/implications), I can say that I have seen very large (and msyterious) contentrations of jellyfish while kayaking in the relatively pristine and healthy waters along the north coast of the Gulf of Alaska.

On one occasion I paddled across a "column" of jellyfish that was at least a mile long, 20-30 feet wide and of unknown depth, thick with moon jellies of various sizes. It was most bizarre but apparently a naturally occuring event. There had to have been hundreds of thousands of them.

If a twigg falls in the forest but nobody is there to hear it, it's probably best because there is bound to be cussing.

by Tom Twigg at 12:51 PM on 12 Jul 2007

Sam,

One or two personal observations are fairly meaningless, statistically. Oceanographers have enough data to tell if jelly fish swarms are increasing. Most ocean fisheries are expected to collapse in the next 40 or so years.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

by biodiversivist at 1:04 PM on 12 Jul 2007

LA Times

Jellyfish featured in that LA Times story, on ocean troubles. I think they were the ones who said generally that the catch of small fishes (herring, anchovy, etc.)

Here's the old gristmill link

Though I'm sure it would take a Monterey Bay expert to give me a solid opinion on that locale ... and two Monterey Bay experts to have an argument ...

by odograph at 1:08 PM on 12 Jul 2007

value of personal observations

Whether or not the proliferation of jellyfish is a securely proved symptom of overfishing, i.e. the hunting, catching and killing of vertebrate fishes beyond what the populations of those fishes can withstand, is something I know nothing about. But, you know, when it comes to things like that, I tend to trust Andrew Sharpless and his colleagues.

Whether or not it is good that jellyfish should proliferate, is a controversy on its own.

Over against that, Sammie's observation (NOT his conclusion) is worth taking seriously. Sometimes anecdotes matter. If you see one genuine non-white swan, you have disproved the assertion, "All swans are white."

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.

by caniscandida at 3:41 PM on 12 Jul 2007

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