Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New UF study shows some sharks follow 'mental map' to navigate seas

10.03.2011
A new study led by a University of Florida researcher uses tracking data of three shark species to provide the first evidence some of the fish swim directly to targeted locations.

Researchers found tiger and thresher sharks showed the ability to orient at large distances, with tiger sharks swimming in direct paths at least 4 miles away and reaching specific resource areas about 30 miles away, said lead author Yannis Papastamatiou, a marine biologist in the division of ichthyology at the Florida Museum of Natural History on the UF campus.

A research highlight of the study in the current edition of the Journal of Animal Ecology will appear in the Thursday issue of the journal Nature.

"This study is important because it uses quantitative methods to try to understand the underlying ecological reasons for animal movement," said Kevin Weng, a marine biologist at the University of Hawaii at Manoa. "Studies such as this one are stepping stones to achieving predictive skill for animal movement, and better understanding of navigation, population dynamics and ecology."

Papastamatiou said the study suggests the sharks have developed a 'mental map' of the area.

"There's been several studies that have shown that marine predators, like sharks, penguins, turtles and tunas, move using particular types of random walks, but there's going to be times when these animals don't move randomly," Papastamatiou said. "This study shows that at times sharks are able to orient to specific features, and in the case of tiger sharks, the distance over which they're performing those directed walks is likely larger than the distance of the immediate range of their sensory systems."

Researchers use the term "directed walk" to describe when a shark is moving toward a known goal rather than randomly swimming.

Researchers re-analyzed tracking data from acoustic transmitters on nine tiger sharks off the south shore of Oahu, Hawaii, in 1999, nine blacktip reef sharks in the lagoons of Palmyra Atoll in the Central Pacific Ocean in 2009, and 15 thresher sharks off the southern California coast in 2010. The animals were followed for at least seven hours and the statistical analysis determined whether the sharks were moving randomly or toward a known goal.

While tiger sharks have acute senses of sight, hearing and smell, their home range covers hundreds of square miles, including resource spots outside their sensory range. As bounce divers, they also almost continuously swim between the surface and about 250 to 330 feet below.

"At times these tiger sharks were swimming across a deep channel, open ocean, often at night," Papastamatiou said. "So the question is, 'What are they orienting to in such a seemingly featureless environment?' It really just highlights how impressive their navigation can be."

Researchers determined adult thresher sharks could orient at greater distances than juveniles, most likely because of their advanced development, Papastamatiou said. The study found blacktip reef sharks only traveled randomly, which has to do with their small home range compared to larger areas covered by thresher and tiger sharks.

Papastamatiou speculated the "mental map" the sharks create may have to do with their ability to sense magnetic fields.

"Probably the most interesting sense and still the most misunderstood is magnetic reception," Papastamatiou said. "There is an increasing amount of evidence that lots of, if not all animals, can to a certain degree detect magnetic fields. That is something that could potentially be used over very large distances because there are gradients in the earth's magnetic field and they could use those as landmarks — so even swimming through open ocean, which seems featureless to us, may not be featureless to sharks if they could detect these magnetic fields."

He said the research would potentially be useful for obtaining accurate population dispersal models for the sharks so that movement patterns can be predicted after changes caused by fishing or the relocation of prey.

Study co-authors include Daniel Cartamil of the University of California San Diego, Christopher Lowe of California State University Long Beach, Carl Meyer and Kim Holland of the University of Hawaii at Manoa and Brad Wetherbee of the University of Rhode Island.

Yannis Papastamatiou | EurekAlert!
Further information:
http://www.ufl.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Stretchable biofuel cells extract energy from sweat to power wearable devices

22.08.2017 | Power and Electrical Engineering

New technique to treating mitral valve diseases: First patient data

22.08.2017 | Medical Engineering

IVAM Marketing Prize recognizes convincing technology marketing for the tenth time

22.08.2017 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>