About alberto de leon(Sting operation- jellyfish "blooms" may endanger fish stocks) vox-updated report ..http://www.fao.org/news/story/en/item/176874/icode/ .http://travel.cnn.com/coming-europe-summer-jellyfish-600901 . http://thechive.com/2013/04/10/jellfish-jellyfish-everywhere-50-photos/ ......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
MEDITERRANEAN AND BLACK SEA .
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................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
MEDITERRANEAN AND BLACK SEA
Cover..... ......................................................................................................................................................................................................................................................................................................................................................................Overfishing, which removes top predators from the sea, is one of the factors behind jellyfish "blooms", or suddenly increased numbers. A "vicious circle" can then follow in which large numbers of medusae feed on fish larvae and juveniles , and "further reduce the resilience of fish populations already impacted by overfishing," according to the report, ...................................................................................................................................................................GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
MEDITERRANEAN AND BLACK SEA
... . .Now European scientists are warning that a surge in the number of jellyfish could threaten not only marine biodiversity, but also the health of tourists in beach resorts around the Mediterranean and Black Sea. ...................................................................................................................................................................“In the last decade … the media are reporting on an increasingly high number of gelatinous plankton blooms,” reads the report. “The reason for these reports is that thousands of tourists are stung, fisheries are harmed and even impaired by jellyfish.” ...................................................................................................................................................................Although noting that significant jellyfish blooms “have been known since ancient times and are part of the normal functioning of the oceans,” the report cites global warming and global over-fishing (which removes jellyfish predators) as causes for exploding jellyfish populations in recent years. .........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
30 May 2013, Rome - Surges in jellyfish populations may be one reason for a drop in fish stocks observed in the Mediterranean and Black Sea, according to a new report published by FAO.
Overfishing, which removes top predators from the sea, is one of the factors behind jellyfish "blooms", or suddenly increased numbers. A "vicious circle" can then follow in which large numbers of medusae feed on fish larvae and juveniles , and "further reduce the resilience of fish populations already impacted by overfishing," according to the report, from FAO's General Fisheries Commission for the Mediterranean.
Jellyfish "might be the proverbial straw that broke the camel's back" says the Review of Jellyfish Blooms in the Mediterranean and Black Sea.
Normally, only the impact of human fishing activities is taken into account in setting sustainable fishing limits, the report says. But jellyfish can also have a high impact on fish eggs and larvae, either directly or by competing for the same food sources. They should thus be considered in any ecosystems-based approach to fisheries management.
Overwhelming impact
The severe effect jellyfish can have on fish stocks was demonstrated in the early 1980s when Mnemiopsis leidyi, a jellyfish species normally resident on the Atlantic, was accidentally introduced into the Black Sea and had such "overwhelming" impact on fish populations that fisheries were put "on their knees".
The problem was only resolved after another invader species Beroe ovate, which feeds on Mnemiopsis, also arrived in the Black sea.
In the Adriatic a drop in fish populations was also observed 20-30 years ago with a successive surges of mauve-coloured, Pelagia noctiluca jellyfish that deliver a vicious sting. The combined effect of Pelagia predation on the one hand and human overfishing on the other played a large part in reducing reproductive adult fish "to a threshold that made recovery of fish populations less effective".
"In the past, the system could cope with episodes of jellyfish abundance , but in the case of the early 1980s blooms, the system went in another direction and is still not back to "normal" in pre-Pelagia years," the report states.
Jellyfish ocean
Jellyfish have now become persistently abundant in almost all the oceans of the world, leading some experts to speak of "a global regime shift from a fish to a jellyfish ocean" in which jellyfish supplant fish.
Although the reasons for the phenomenon are not fully understood, they may include, besides overfishing:
• Global warming, which enhances species that thrive at tropical latitudes.
• Eutrophication, which increases nutrients in the water.
• Widespread use of sea walls to prevent coastal erosion and the large number of tourist harbours, which make an ideal habitat for those jellyfish who go through a stage as polyps in their early lives.
Measures advocated to prevent or cope with jellyfish blooms include:
• Incorporate jellyfish research into fisheries research.
• Develop jellyfish products for food and medicine. Some jellyfish species are a food source in several countries.
• Among other possibilities, the discovery of an "immortal jellyfish", Turritopsis nutricula, capable of reversing its ageing process, holds out the promise of developing powerful rejuvenation products for humans.
• Establish early warning systems of jellyfish blooms, with protective barriers for aquaculture farms.
• Taking steps to reduce overfishing, greenhouse gas emissions and the causes of eutrophication "would undoubtedly improve environmental quality at large and might, thus, also reduce the present prevalence of jellyfish," the report adds.
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Stinging jellyfish are besieging shorelines across the Mediterranean, threatening the health of tourists.
........................................................................................................
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
| Giant jellyfish |
MEDITERRANEAN AND BLACK SEA .
......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................| GIANT JELLYFISH |
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
MEDITERRANEAN AND BLACK SEA
Cover..... ......................................................................................................................................................................................................................................................................................................................................................................Overfishing, which removes top predators from the sea, is one of the factors behind jellyfish "blooms", or suddenly increased numbers. A "vicious circle" can then follow in which large numbers of medusae feed on fish larvae and juveniles , and "further reduce the resilience of fish populations already impacted by overfishing," according to the report, ...................................................................................................................................................................GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN
ISSN 1020-9549
STUDIES AND REVIEWS
No. 92 2013
REVIEW OF JELLYFISH BLOOMS IN THE
MEDITERRANEAN AND BLACK SEA
... . .Now European scientists are warning that a surge in the number of jellyfish could threaten not only marine biodiversity, but also the health of tourists in beach resorts around the Mediterranean and Black Sea. ...................................................................................................................................................................“In the last decade … the media are reporting on an increasingly high number of gelatinous plankton blooms,” reads the report. “The reason for these reports is that thousands of tourists are stung, fisheries are harmed and even impaired by jellyfish.” ...................................................................................................................................................................Although noting that significant jellyfish blooms “have been known since ancient times and are part of the normal functioning of the oceans,” the report cites global warming and global over-fishing (which removes jellyfish predators) as causes for exploding jellyfish populations in recent years. .........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
Sting operation - jellyfish "blooms" may endanger fish stocks
With overfishing, "vicious circle" created
Abnormal Jellyfish bloom in the Mediterranean.
Overfishing, which removes top predators from the sea, is one of the factors behind jellyfish "blooms", or suddenly increased numbers. A "vicious circle" can then follow in which large numbers of medusae feed on fish larvae and juveniles , and "further reduce the resilience of fish populations already impacted by overfishing," according to the report, from FAO's General Fisheries Commission for the Mediterranean.
Jellyfish "might be the proverbial straw that broke the camel's back" says the Review of Jellyfish Blooms in the Mediterranean and Black Sea.
Normally, only the impact of human fishing activities is taken into account in setting sustainable fishing limits, the report says. But jellyfish can also have a high impact on fish eggs and larvae, either directly or by competing for the same food sources. They should thus be considered in any ecosystems-based approach to fisheries management.
Overwhelming impact
The severe effect jellyfish can have on fish stocks was demonstrated in the early 1980s when Mnemiopsis leidyi, a jellyfish species normally resident on the Atlantic, was accidentally introduced into the Black Sea and had such "overwhelming" impact on fish populations that fisheries were put "on their knees".
The problem was only resolved after another invader species Beroe ovate, which feeds on Mnemiopsis, also arrived in the Black sea.
In the Adriatic a drop in fish populations was also observed 20-30 years ago with a successive surges of mauve-coloured, Pelagia noctiluca jellyfish that deliver a vicious sting. The combined effect of Pelagia predation on the one hand and human overfishing on the other played a large part in reducing reproductive adult fish "to a threshold that made recovery of fish populations less effective".
"In the past, the system could cope with episodes of jellyfish abundance , but in the case of the early 1980s blooms, the system went in another direction and is still not back to "normal" in pre-Pelagia years," the report states.
Jellyfish ocean
Jellyfish have now become persistently abundant in almost all the oceans of the world, leading some experts to speak of "a global regime shift from a fish to a jellyfish ocean" in which jellyfish supplant fish.
Although the reasons for the phenomenon are not fully understood, they may include, besides overfishing:
• Global warming, which enhances species that thrive at tropical latitudes.
• Eutrophication, which increases nutrients in the water.
• Widespread use of sea walls to prevent coastal erosion and the large number of tourist harbours, which make an ideal habitat for those jellyfish who go through a stage as polyps in their early lives.
Measures advocated to prevent or cope with jellyfish blooms include:
• Incorporate jellyfish research into fisheries research.
• Develop jellyfish products for food and medicine. Some jellyfish species are a food source in several countries.
• Among other possibilities, the discovery of an "immortal jellyfish", Turritopsis nutricula, capable of reversing its ageing process, holds out the promise of developing powerful rejuvenation products for humans.
• Establish early warning systems of jellyfish blooms, with protective barriers for aquaculture farms.
• Taking steps to reduce overfishing, greenhouse gas emissions and the causes of eutrophication "would undoubtedly improve environmental quality at large and might, thus, also reduce the present prevalence of jellyfish," the report adds.
....................................................................................................................................................................
Coming to Europe this summer -- jellyfish
A dramatic increase in jellyfish populations in the Mediterranean and Black Sea may keep travelers out of the water this summer
Sharks. Sea Snakes. Sewage.
Lots of unpleasant things can keep us out of the ocean, ruining an otherwise enjoyable beach holiday.
Perhaps no sea creature makes swimmers quite so paranoid as jellyfish -- “gelatinous macrozooplankton” if you really want to make yourself feel squeamish.
Now European scientists are warning that a surge in the number of jellyfish could threaten not only marine biodiversity, but also the health of tourists in beach resorts around the Mediterranean and Black Sea.
According to a report titled “Review of Jellyfish Blooms in the Mediterranean and Black Sea,” written by Fernando Borea for the General Fisheries Commission for the Mediterranean and the United Nations, scientists are catching up to what travelers in the Med have been experiencing for years.
“In the last decade … the media are reporting on an increasingly high number of gelatinous plankton blooms,” reads the report. “The reason for these reports is that thousands of tourists are stung, fisheries are harmed and even impaired by jellyfish.”
Although noting that significant jellyfish blooms “have been known since ancient times and are part of the normal functioning of the oceans,” the report cites global warming and global over-fishing (which removes jellyfish predators) as causes for exploding jellyfish populations in recent years.
“There are now beaches on the [Italian] island of Lampedusa, which receive 300,000 tourists a year, where people can only swim for a week in the summer,” according to Salento University (Italy) professor Stefano Piraino, in an article in the Guardian.
According to the same Guardian article, Barcelona’s Institute of Marine Sciences “has detected a surge this spring in one of the most poisonous species, the mauve stinger or Pelagia noctiluca, along the coast of Catalonia and Valencia.” The coastlines most badly affected by the overall surge in jellyfish populations include Malta, Sardinia, Sicily and areas of Israel and Lebanon, the articlesays.
According to the General Fisheries Commission for the Mediterranean report, the region’s first case of a lethal sting from a jellyfish occurred in Sardinia in 2010.
“Sea-based tourism is one of the main sources of income in the whole Mediterranean Sea. If stinging jellyfish persist, stung tourists can cancel their reservations or reduce the length of their stay, with a reduction of revenues from tourism,” reads the study.
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