Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Loggerhead turtle territories defined by water characteristics in the Western Mediterranean

04.12.2008
Spanish researchers have shown that the salinity of sea water could act as a “barrier”, preventing the turtles from moving between the areas of the Western Mediterranean. This is why loggerhead turtles from the south and north of the Western Mediterranean do not mix as juveniles. This finding could help in the development of measures to protect this migratory species.

The Franco-Spanish research group started to tag more than 1,500 immature loggerhead turtles (Caretta caretta) in 1993, of which 36 were progressively recaptured until 2005 at an average interval of 390 to 462 days. The majority of the turtles were recaptured in the same region where they were tagged.

The results of this tagging exercise where recently published in Scientia Marina, and reveal only limited exchanges between the immature turtles as a result of a “barrier” dividing the species and their territories, with the Atlantic ones remaining in the south of the Western Mediterranean and the Eastern Mediterranean ones staying in the north of the Western Mediterranean.

Mónica Revelles, lead author of the study and a researcher in the Animal Biology Department at the University of Barcelona (UB), tells SINC that “before, we did not know the Atlantic turtles stayed in the southern Mediterranean, and the Mediterranean ones in the northern part, but the genetic data and satellite tracking led us to suspect this.”

The study shows the immature individuals are oceanic (unlike the adults, which remain close to the coast), but that they do not stray beyond the areas they are used to. For this reason, the experts believe that water salinity could play a significant role.

Maps of ocean currents and salinity show that salinity is lower in water masses moving around the southern area than in those circulating around the northern part of the Western Mediterranean.

The fact that exchanges between the turtles of Atlantic and Mediterranean origin are limited is “important”, because projects to protect immature turtles in the Western Mediterranean will have to be divided into at least two groups. Revelles says “the studies carried out in the northern and southern areas will relate to the Mediterranean and Atlantic populations, respectively”.

Limited exchanges between the two groups, and human activities such as long line fishing, could impact on those turtles travelling through the southern Mediterranean and nesting along the Atlantic coasts. This is why scientists insist upon the need for measures to protect this migratory species.

Same species, different genes

In terms of origin and place of birth, the Atlantic turtles tend to stay within the southern Mediterranean, while the Mediterranean ones establish themselves in the northern area, although the occasional individual does move from one area to the other, with some even travelling as far as the Caribbean. “This limited exchange between the north and the south means the populations do not interbreed,” says Revelles.

The researchers say the different origins of the loggerhead turtles mean those from the south and north of the Mediterranean exhibit “slightly” different behaviours. They are the same species, but with genetic and morphological differences between the Atlantic and Eastern Mediterranean populations, with the Atlantic animals being larger, while the Mediterranean ones grow less but become adult earlier.

The Western Mediterranean, where the immature animals from both species are found, is the feeding habitat for juvenile turtles. They return to the area where they were born in order to reproduce – the east of the Mediterranean for those from the north of the Western Mediterranean, and the Atlantic for those from the south of the Western Mediterranean.

In addition to the UB, the Spanish Institute of Oceanography (IEO), the Marine Animal Rescue Centre (CRAM), the University of Valencia, the University of Montpellier, France, and the University of Perpignan, also in France, took part in the study.

SINC Team | alfa
Further information:
http://www.plataformasinc.es

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

NSF-supported researchers to present new results on hurricanes and other extreme events

19.07.2018 | Earth Sciences

Scientists uncover the role of a protein in production & survival of myelin-forming cells

19.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>