Here come the jellies


in Science, The environment

What do you get when you combine overfishing with large-scale nutrient runoff from industrial farms into rivers and the sea? Plagues of jellyfish:

The Namibian coast, for instance, used to be “hugely productive in fish,” [UBC fisheries graduate student Lucas Brotz] says, “and now it is entirely dominated by jellyfish. Things appear to be going that way in the Middle East, South Pacific, the Gulf of Mexico and the Mediterranean.”

This is what unlimited fishing with ever-better gear inevitably produces – short term profits for a few years followed by severely degraded ecosystems indefinitely.

{ 10 comments… read them below or add one }

Milan March 31, 2008 at 2:49 pm

More on fisheries:

Tomorrow Today report
Friday, March 14th, 2008

New UNEP report: ‘In Dead Water’
Monday, February 25th, 2008

Fishing should never be subsidized
Wednesday, January 23rd, 2008

Costly cod
Friday, January 18th, 2008

Advertising over-fishing
Tuesday, January 8th, 2008

Films and fish stocks
Tuesday, August 21st, 2007

Dolphin safe tuna
Wednesday, February 14th, 2007

Lomborg on fish
Thursday, June 29th, 2006

More bad news for world fisheries
Thursday, January 5th, 2006

. April 8, 2008 at 11:15 am

Title: Jellyfish Salad
Yield: 1 Serving


125 g (4 oz) Salted jellyfish
1 lg Cucumber
1/2 c Small peeled cooked prawns
125 g (4 oz) Roast chicken,
-preferably b
2 tb Vegetable or peanut oil
1 Spring onion, finely chop’d
1 tb Fish sauce (nuoc mam)
Fresh coriander leaves,
Black pepper
2 tb Pickled carrot
2 tb Roasted peanuts, chopped


Soak the jellyfish in hot water for 2 hours, changing the water
twice. Drain and cut into thin strips. Peel the cucumber, cut in
halves lengthwise and slice thinly. Place in a dish with 1 teaspoons
salt and leave for 10 mins. Rinse and drain.

Shred the chicken. Saute the chicken and prawns briefly in the oil
adding the chopped onion and fish sauce. Add the jellyfish and toss
in the pan. Remove and leave to cool, then mix with the remaining
ingredients and pile onto a small plate.

(C) Copyright : Vietnam – The Pleasure Of Cooking Mini-Series.

Anon April 9, 2008 at 10:29 am
. August 22, 2008 at 2:49 pm
. September 2, 2008 at 10:18 am

A profusion of jellyfish is often described as an invasion or an attack. Which is laughable, given the guiding principle of jellyfish behavior—”whatever.” No brain, no spine; they don’t have the capacity to plan a beach invasion. We bump into them, and because we’re too big to eat, they perceive us as attackers.

Planning is not their forte. In place of a brain, jellies have a nerve net. Jellyfish are the free-floating relatives of sea anemones and corals, much older than fish, and not much changed for more than 600 million years. They ruled the ocean, in their passive way, when there was almost nothing but ocean. Now they drift into their food or their food drifts into them. The pulsing creates a current that pulls prey within reach.

. October 29, 2008 at 3:30 pm

Jelly Smackdown Forces Reactor to Close

Last week, a smack of moon jellies jammed the Diablo Canyon nuclear power plant off the California coast. The rise of slime and the closure of power plants. Just another shifting baseline.

. November 4, 2009 at 4:21 pm

Japanese fishing trawler sunk by giant jellyfish
A 10-ton fishing boat has been sunk by gigantic jellyfish off eastern Japan.

By Julian Ryall in Tokyo
Published: 7:00AM GMT 02 Nov 2009

The trawler, the Diasan Shinsho-maru, capsized off Chiba`as its three-man crew was trying to haul in a net containing dozens of huge Nomura’s jellyfish.

Each of the jellyfish can weigh up to 200 kg and waters around Japan have been inundated with the creatures this year. Experts believe weather and water conditions in the breeding grounds, off the coast of China, have been ideal for the jellyfish in recent months.

The crew of the fishing boat was thrown into the sea when the vessel capsized, but the three men were rescued by another trawler, according to the Mainichi newspaper. The local Coast Guard office reported that the weather was clear and the sea was calm at the time of the accident.

. November 18, 2009 at 3:54 pm

The rise of slime

Nov 17th 2009
Warmer water is exacerbating problems in the oceans

THE fishermen of Kokongi, Japan, have seen record hauls this year. They are not, however, very happy. Their nets are trapping jellyfish: giant, gelatinous, wobbly and worthless. Jellyfish were once rare along these shores, but are now an almost annual occurrence.

It is the same story in many other parts of the world. Jellyfish are blamed for damaging fishing, shutting down power and desalination plants, and upsetting swimmers.

There is one man, though, who may be justified in saying “I told you so”. His name is Jeremy Jackson of the Scripps Institution of Oceanography, in San Diego, and for the past decade he has been touring the world giving a depressing presentation he calls the “Brave New Ocean”.

Dr Jackson is a commanding presence in any room, with his long, white ponytail and booming voice. The story he has been telling is quite simple, that the world’s oceans are undergoing a profound shift because of overfishing, habitat destruction and warming. The effects are seen in the rise of jellyfish, and also in algal blooms and “blobs”, something he describes as “the rise of slime”.

Indeed, a report recently identified increases in marine mucilage, a seasonal phenomenon consisting of a gelatinous mess of decomposing sea animals, plants, faeces and anything else that has become entrapped in the slime. Mucilage forms when decomposing material fails to sink rapidly to the bottom of the sea. In certain circumstances it can spread over hundreds of kilometres.

Peer reviewed science October 7, 2011 at 6:26 pm

Rise of the Jellyfishes

Human-induced changes to marine systems, such as overfishing, habitat destruction, and climate change, have resulted in large declines in top fish predators. In some such systems, a correlated increase in large jellyfishes has occurred, leading some to suggest that anthropogenic impacts on marine systems may result in a shift from planktivorous fish-dominated to jellyfish-dominated trophic webs. This shift seems paradoxical because actively swimming and hunting fish appear much more efficient than slow, drifting jellyfish. Acuña et al. (p. 1627), however, show that in terms of relative prey consumption rates, fish and jellyfish are similar. It seems that jellyfish make up for their inability to track prey actively by being large and thus encounter a greater number of prey items.

. May 1, 2020 at 9:27 pm

“It may be that the meek will not ultimately inherit the Earth: jellyfish will. Because they can tolerate warming seas, acidification and pollution, some scientists believe that they may be set to outlast less robust animals. Others reckon that recent blooms simply reflect natural fluctuations in numbers.”

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