Global warming of ocean currents causes invasion of killer jellyfishgreenspun.com : LUSENET : TB2K spinoff uncensored : One Thread
Jellyfish overtake Gulf of Mexico Scientists shocked by threat to ecosystem and fishing By Ben Raines NEWHOUSE NEWS SERVICE
MOBILE, Ala., Sept. 11 Jellyfish are swarming through the northern Gulf of Mexico in unprecedented numbers, signaling an ecological shift that could mean sweeping and catastrophic changes for Gulf fish populations. Hordes of jellies are positioned in prime spawning areas just as breeding season for many popular gamefish kicks into high gear. Scientists say the animals have already started eating eggs and larva at an alarming rate.
IM JUST dazed, Joanna Shultz, a fish larvae specialist with the National Marine Fisheries Service lab in Pascagoula, Miss., said after learning the extent of the jellyfish swarms, both inshore and offshore. This is pretty serious. It could be totally devastating. Scientists say the jellyfish are just taking advantage of a series of major changes that man has brought about in the Gulf of Mexico, where native jellyfish populations have been rising steadily for at least the last 13 years, as indicated by data from the National Marine Fisheries Service. This explosion of native jellies could, in itself, threaten the future of the commercial and recreational fishery in the northern Gulf, scientists say. INVADERS ABOUND But it is an invading exotic species, the Australian spotted jellyfish, that scientists consider the real wild card. The 25-pound jellies have established themselves in the passes between the barrier islands that divide the Mississippi Sound from the Gulf, creating a nearly impenetrable wall that tiny larval fish, shrimp and crabs cannot pass through without becoming dinner for the invaders. Scientists report that the Australian jellies are proving to be incredibly efficient predators, scouring the water from the surface down to the bottom, consuming not only the eggs and larvae but also the plankton the larvae need to survive. In the next few weeks redfish, speckled trout, white trout and Spanish mackerel will be spawning outside the barrier islands, their eggs and larvae drifting on currents that will carry them straight into the jellyfish gantlet. Advertisement
Add to that the massive numbers of native moon jellyfish swarming far offshore in a major king mackerel and red snapper spawning area, and scientists begin to talk in terms of a disaster. These guys are eating a hole in the water, said Monty Graham, a jellyfish scientist with the Dauphin Island Sea Lab and one of only about 70 people in the world who study jellyfish. Its not just a jellyfish problem. Its an ecological problem, and a bad one. ... This could take decades to deal with. OIL RIGS SEEN AS FACTOR A growing number of scientists attribute much of the sharp rise in the native jellies to the proliferation of offshore oil rigs, artificial reefs and other man-made structures, which increase underwater breeding habitats for jellyfish. And they cite two other human factors likely contributing to the ballooning jellyfish population: a heavy infusion of excess nitrogen that causes unnatural plankton blooms the jellyfish thrive on, and the overfishing of Gulf menhaden, which reduces the jellyfishs natural competition in the hunt for food.
What remains to be seen is whether the Australian newcomers can play these same cards to their advantage and become a more widespread and permanent threat to the Gulf fishery. Australian spotted jellies, officially known as Phyllorhiza punctata, were first sighted in Mobile Bay in May, a long way from their native home in the Pacific. Scientists theorize that they hitched a ride into the Gulf on a ship coming through the Panama Canal and colonized the Caribbean some time ago. This year, apparently for the first time ever, they rode a current into the upper Gulf. Scientists say the thousands now swarming in the Mississippi Sound arrived as full-grown adults the size of basketballs. What has fishery experts worried is that these jellies are in the passes between the barrier islands, as well as in the mouth of Lake Bourne, one of the major Mississippi River estuaries in Louisiana. To make matters worse, the newcomers are mating like mad, and it is possible an even larger crop could hatch in the northern Gulf next spring. IM AN ALARMIST NOW When Graham first heard about the phyllorhiza infestation, he said he didnt want to be an alarmist. That has changed. Im an alarmist now, he said, but an alarmist with data. That data, obtained during a two-week research cruise in the Gulf, shows that the invaders have a predilection for eating fish eggs and larvae. And it shows that they have situated themselves in extremely high concentrations in the places where they could potentially do the most damage to fish stocks in the northern Gulf. In addition to the sport fish that may be hard hit by the jellies, commercially important species such as shrimp, menhaden, anchovies and crabs spawn outside the barrier islands. Their eggs and larvae must float through the passes to get to the inshore nursery area that runs from Louisiana to Alabama, where they grow to adult size. Grahams data indicates that scarcely a single egg or larva can run the intense jellyfish gantlet set up in the passes. The jellies are so concentrated, it appears a person could use them as stepping stones from one island to another. These things are incredibly efficient at turning the water over, cleaning it of everything in it, he said. Were finding them with 200 fish eggs in their guts. The jellies digest their gut contents every two hours, so right now, they are each eating about 2,400 eggs a day. Graham said their consumption is limited only by the number of eggs and small larvae in the water, and as breeding season peaks this fall, theyll consume even more. Each jellyfish can filter 50 cubic meters of water a day, cleaning it of nearly every living thing smaller than a BB. PLANKTON AT RISK These jellies arent eating the large fish or even the minnowlike fingerlings. They concentrate on plankton, that pervasive blanket of tiny creatures, both plant and animal, that ultimately fuels the entire Gulf ecosystem. The problem is that the jellyfish are, in a sense, taking this plankton out of the mouths of mature filter-feeding fish and fish larvae, which compete with the jellyfish for the plankton. You really have two problems in terms of commercially important fish, said Harriet Perry, director of the fisheries section of the Gulf Coast Research Laboratory in Mississippi. First, the jellies are ingesting the larvae and eggs of these commercially important species, and then the fish larvae must compete with these incredibly efficient jellies for the same food source. That impact ripples throughout the Gulfs ecosystem, because these filter feeders, such as anchovies and menhaden, are primary food sources for the larger fish in the Gulf. But Perry said she isnt worried simply about the effects on next years crop of juvenile fish, which she says could be dramatic. She fears that the phyllorhiza have the potential to establish themselves here, permanently altering the food web. This is an extraordinary biological event. I have worked in this area for 33 years, and Ive never seen anything like this, Perry said. The fact that these things are feeding on the base of the food chain and doing it so successfully could have huge impacts for the Gulf.
MSNBC environment coverage
BLACK SEA EXPERIENCE The fear is that the phyllorhiza will act like a waterborne version of the imported fire ant, taking advantage of prime conditions not available in its native land. It is not unprecedented in the jellyfish world. The ctenophores, a small native North American species common in Mobile Bay, invaded the Russian Black Sea, carried in the ballast water of a cargo ship. They proliferated wildly and caused the total collapse of a once thriving anchovy fishery there.
Such a total collapse in the Gulf is less likely, because its a much more open and diverse water body and ultimately may be more resilient. Still, scientists worry. Without their normal South Pacific predators and parasites to limit their population growth, these jellies could spread themselves around the Gulf in an arc that widens every year. And if they continue to set up in front of other important Gulf estuaries, they could all but eliminate the commercial fish harvest in those regions.
-- killer blobs (firstname.lastname@example.org), September 12, 2000
The data that I've been researching from experts in the field indicates that these jellyfish will probably get into the sewage and water treatment systems in the state of Texas.
They are likely to breed rapidly in large cities like Dallas, where they will come up through the toilets of unsuspecting real-estate salesmen and sting them in the buttocks or the scrotum.
-- Ed You'redone (email@example.com), September 12, 2000.
That's right Ed, they're gonna get those people in Texas!
Lookout CPR, they're comin to get ya! You should start a campaign of denial and prove to the world that there is no way they can invade Texas. Take at least 2 years off of work, and spread the word throughout the Internet. Sue me if you want, but I have proof, they're comin to get ya!
-- Harry North (TEO@Texas.AWKI), September 12, 2000.
Australian spotted jellies are officially known as Phyllorhiza punctata for good reason. Don't f**k around with 'em - they're real buggers and savage. They've been known to savour and take off with wayward Yankee tourists who brave our Southern Ocean... mind you the authorities say they are known to pass-by the odd Texan or two; even jellies have trouble digesting certain things.
Cheers from OZ
-- Pieter (firstname.lastname@example.org), September 12, 2000.
Blah blah blah. And when a cooler than normal current runs through the area, the spineless blobs will die off, leaving the earth-worshippers to run to their next scam- suddenly getting quiet about THIS "global disaster".
Blah blah blah
-- BLAH BLAH BLAH (email@example.com), September 12, 2000.
"they are known to pass-by the odd Texan or two; even jellies have trouble digesting certain things."
Bwaaahaaahaaahaa!! Must have been Creeper who turned them off!
-- (firstname.lastname@example.org), September 12, 2000.