Fewer Fish Leads to Jellyfish Explosion

[Anonymous]

http://www.livescience.com/animalworld/ ... osion.html

Fewer Fish Leads to Jellyfish Explosion

By Robert Roy Britt
LiveScience Managing Editor
posted: 10 July 2006
12:00 pm ET

Nature abhors a vacuum. Wipe out one creature, and another will move in. Mammals leveraged this principle when the reign of dinosaurs ended.

Now in a smaller way, jellyfish are taking over.

In a region off the west coast of Africa in the Atlantic Ocean, heavy fishing in recent decades has depleted fish stocks while leading to increased numbers of jellyfish.

Now with some hard data in hand, scientists are calling it a jellyfish explosion.

In fact the jellyfish are so numerous in the study area that they now represent more biomass than all the fish combined. Their numbers, ironically, are beginning to "significantly interfere with fishing operations," the researchers report in the July 12 issue of the journal Current Biology.

Andrew Brierley of the University of St. Andrews and colleagues used echosounders and trawl nets to find out what's in the water along the Namibian shelf, between the borders of Angola and South Africa. Sardines and anchovies were once abundant.

The total biomass of jellyfish in the region is now estimated to be more than three times that of fish.

Similar increases in jellyfish biomass are occurring in many locations around the world, the scientists note. Overfishing and climate change might both contribute to the phenomenon. Jellyfish have few predators, the scientists say, so if fish are depleted and nutrients are available, the jellyfish do quite well.

Meanwhile, a study last year found that jellyfish are invading the globe by hitchhiking from ocean to ocean aboard ships.

 

[Anonymous]

And in Japan, they're having similiar problems with VW bug sized jellies

 

[Anonymous]

Don't Jellies eat fish though? Seems strange for one population to explode when their food source is gone.

VW sized ones?? EEEEEEEP

 

[Anonymous]

Fish also eat jellies, as do other jellies.

 

[liquid]

Good article. I added the link to our Marine News section on AAOLM:

http://www.advancedaquarist.com/marinenews/

FYI there's also an

RSS feed for the news as well in case folks want to subscribe:

http://www.advancedaquarist.com/marinenews/RSS



Shane

 

[WRASSER]

I thought turtles ate jellies?

 

[Anonymous]

Them too

 

[Anonymous]

And humans :lol:

 

[Meloco14]

I thought turtles ate jellies?

And humans :lol:

I hate those human eating turtles! :wink:

 

[Anonymous]

Me too. That is why they are hunted so hard. People are getting tired of loosing relatives to the turtles. TMNT was no joke :lol:

 

[Kalkbreath]

This is one of the main reasons the increasing C02 levels in the Atmosphere are down an bit over the last few years (the rate of of increase).
The increase in biomass in the oceans is acting as a C02 sink.
Kinda like a growing forrest locks in Carbon and C02 on land.
Too bad fish stocks are not rebounding as well.
Many scientists think that the whole excess C02 thing has always been due to depleted biomass in the oceans.
The C02 increases began before the industrial age. (1800)
"Effect" cant come before "Cause".
even though C02 increases began before humans started burning fossil fuels, ... fishing was big time in 1800.
Twenty mamal specias had already become severely depleated or extinct before 1850.
like the great Auk, the walrus, Stellars sea cow, the gray whale and other whales.
Fishing and the number of biomass in the Oceans seems directly connected to Atmosphere C02 levels.
When the bio mass increases, the Co2 levels fall.
During World War II ( a time when little fishing took place )
Co2 levels in the world actually went down !
It was the only time in the last 200 years the level decreased.
It was also the only time that fish stocks in the oceans rebounded.
The lack of fishing pressures during that ten year period was all that was needed to reverse the global warming Co2 trend.
Perhaps the Jellies can do like wise.................

 

[Anonymous]

now now people... what are your favorite places to travel to?