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 When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

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: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>