Nav: Home

Jellyfish counterattack in winter

December 13, 2010

A study carried out over 50 years by an international team, with the participation of the Balearic Oceanography Centre of the Spanish Institute of Oceanography (IEO) has confirmed an increase in the size and intensity of proliferations of the jellyfish Pelagia noctiluca. There are several complex reasons for this - over-fishing and the current increase in sea water temperatures.

"Since 2002, these organisms have become increasingly frequently found in the north east Atlantic in winter, since winters have been warmer, and they have tended to appear earlier and spend more time in their annual cycle there", María Luz Fernández de Puelles, the only Spanish co-author of the study, and a researcher at the IEO's Balearic Oceanography Centre, tells SINC.

The study, which has been published in the journal Biology Letters, brings together 50 years of analysis and shows that warmer winters favour the entry of the surface current into the Mediterranean Sea past Gibraltar, creating ideal conditions for the jellyfish Pelagia noctiluca. This species proliferates along Spanish coasts, where there are more food resources than in oceanic areas.

"We have shown that they can reproduce rapidly if the conditions are right, and can reach large densities throughout the whole year, particularly if winters are warm", the marine biologist explains.

The international team used molecular methods to study the increase in the frequency of this group of cnidaria in the North Sea from 1958 to 2007, a period covering the general change in the hydro-climatic regime from cold to warm observed since 1980. "The records for the Mediterranean are much more recent and not as long or continuous, but they further strengthen the study", says Fernández de Puelles.

Adult Pelagia noctiluca have been recorded in various parts of the western Mediterranean, including the Balearic Islands. Their abundance was particularly striking in the autumn and winter of 2007 and in the spring of 2010, as well as in the summers.

According to existing data for the Mediterranean, these proliferations have a 12-year frequency, with most of them remaining for four years. "However, since 1998 these periods have become shorter and more frequent", explains Fernández de Puelles.

Consequences for fisheries and tourism

The increase in jellyfish over the course of the year "directly" affects fisheries, fish farming and tourism "because of the jellyfishes' toxic effects and the poison in their tentacles, and because they appear particularly in the summer, having a significant socioeconomic impact", says Fernández de Puelles.

According to the expert, the increase in the number of jellyfish and the length of time that they remain is primarily due to over-fishing, but hydroclimatic effects such as climate change and the current warming of the sea also have an impact.

Pelagia noctiluca is a jellyfish from the class of the Scyphozoa with a complex and long life cycle, a very extensive range in the warm waters of the Atlantic and Mediterranean, and which usually lives in pelagic habitats (the area of oceans closest to the surface), but also at a certain depth, which makes them difficult to study. This animal can form 'enormous blooms', which are visible from Spanish coasts and beaches.

"Jellyfish are very voracious predators at the top of the trophic network. They feed directly on fish larvae and compete with other zooplankton organisms for food, meaning that they drastically alter the trophic structure of marine ecosystems", says the scientist. "Further studies should be carried out into the impact of this", she concludes.

-end-

References: Licandro, P.; Conway, D.V.P.; Yahia, M.N. Daly; Fernández de Puelles, M.L.; Gasparini, S.; Hecq, J.H.; Tranter, P.; Kirby, R.R. "A blooming jellyfish in the northeast Atlantic and Mediterranean", Biology Letters 6(5): 688-691, 23 de octubre de 2010.

FECYT - Spanish Foundation for Science and Technology

Related Jellyfish Articles:

Jellyfish fluorescence shines new light on DNA copying
Scientists at the University of York have used florescent proteins from jellyfish to help shed new light on how DNA replicates.
Should you pee on a jellyfish sting? (video)
We all know the evils that come from a run-in with a jellyfish's tentacles.
Hawaii scientists scrutinize first aid for man o' war stings
University of Hawai'i researchers investigated which commonly recommended first aid actions are the most effective for Physalia, man 'o war jellyfish, stings.
Tracing the puzzling origins of clinging jellyfish
The first genetic study of the diversity of clinging jellyfish populations around the globe has discovered some surprising links among distant communities of jellies and also revealed there may be more than one species of the infamous stinger.
Current jellyfish sting recommendations can worsen stings
Researchers at the University of Hawai'i - Mānoa (UHM) investigated whether commonly recommended first aid actions such as rinsing with seawater or scraping away tentacles lessen the severity of stings from two dangerous box jellyfish species.
Bee alert but not alarmed
An Australian-first national analysis of 13 years' data on bites and stings from venomous creatures reveals Australia's towns and cities are a hot-spot for encounters.
Brazilian study compiles data on 958 types of South American jellyfish
Detailed information on 958 distinct morphological types of jellyfish that inhabit the Atlantic and Pacific coasts of South America has been compiled in a census published in Zootaxa, the leading zoological taxonomy journal.
Nomads no more, leatherback turtles find permanent coastal home
Endangered leatherback sea turtles are known for their open-ocean migratory nature and nomadic foraging habits - traveling thousands of miles.
Jellyfish help scientists to fight food fraud
Animals feeding at sea inherit a chemical record reflecting the area where they fed, which can help track their movements, according to a new study by scientists from the University of Southampton.
Predicting jellyfish 'invasions' at coastal power stations
Scientists at the University of Bristol are working with the energy industry to develop an 'early warning tool' to predict the sudden, en masse appearance of jellyfish swarms which can cause serious problems by clogging the water intakes of coastal power plants.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: Radiolab

Oliver Sipple
One morning, Oliver Sipple went out for a walk. A couple hours later, to his own surprise, he saved the life of the President of the United States. But in the days that followed, Sipple's split-second act of heroism turned into a rationale for making his personal life into political opportunity. What happens next makes us wonder what a moment, or a movement, or a whole society can demand of one person. And how much is too much?
Now Playing: TED Radio Hour

Future Consequences
From data collection to gene editing to AI, what we once considered science fiction is now becoming reality. This hour, TED speakers explore the future consequences of our present actions. Guests include designer Anab Jain, futurist Juan Enriquez, biologist Paul Knoepfler, and neuroscientist and philosopher Sam Harris.