Jellyfish counterattack in winterDecember 14, 2010
"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.
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 Current Events and Jellyfish News Articles
Evolution of the back-to-belly axis
Most animals have a dorso-ventral (back-to-belly) body axis, which determines for instance the localized position of the central nervous system, dorsal in humans, ventral in insects.
Study projects unprecedented loss of corals in Great Barrier Reef due to warming
The coverage of living corals on Australia's Great Barrier Reef could decline to less than 10 percent if ocean warming continues, according to a new study that explores the short- and long-term consequences of environmental changes to the reef.
It is no secret that typhoons are capable of churning the seas and wreaking destruction.
550 Million Year Old Fossils Provide New Clues about Fossil Formation
A new study from University of Missouri and Virginia Tech researchers is challenging accepted ideas about how ancient soft-bodied organisms become part of the fossil record.
New study shows the importance of jellyfish falls to deep-sea ecosystem
This week, researchers from University of Hawai'i, Norway, and the UK have shown with innovative experiments that a rise in jellyfish blooms near the ocean's surface may lead to jellyfish falls that are rapidly consumed by voracious deep-sea scavengers.
Scientists pioneer microscopy technique that yields fresh data on muscular dystrophy
Scientists at USC have developed a new microscopy technology that allows them to view single molecules in living animals at higher-than-ever resolution.
Shift in Arabian Sea Plankton May Threaten Fisheries
A growing "dead zone" in the middle of the Arabian Sea has allowed plankton uniquely suited to low- oxygen water to take over the base of the food chain. Their rise to dominance over the last decade could be disastrous for the predator fish that sustain 120 million people living on the sea's edge.
Marine scientists use JeDI to create world's first global jellyfish database
An international study, led by the University of Southampton, has led to the creation of the world's first global database of jellyfish records to map jellyfish populations in the oceans.
Science: Surprising Species Shake-up Discovered
The diversity of the world's life forms - from corals to carnivores - is under assault. Decades of scientific studies document the fraying of ecosystems and a grim tally of species extinctions due to destroyed habitat, pollution, climate change, invasives and overharvesting.
New order of marine creatures discovered among sea anemones
A deep-water creature once thought to be one of the world's largest sea anemones, with tentacles reaching more than 6.5 feet long, actually belongs to a new order of animals.
More Jellyfish Current Events and Jellyfish News Articles