Loggerhead Sea Turtles: the compass of the sea

I’ve got a confession to make. At times I park my car, go into a store, and when I come out I have to use my key fob to beep my way back to my car. I can’t tell you how many cars I lost before I bought a car with an electric key fob. That is why I have always been amazed at how animals can migrate thousands of miles and find there way back to the same locations months and years later.

Recently a new study from the University of North Carolina thinks it has unlocked the secret of the Loggerhead Sea Turtle’s migration.

The BBC reported “although several species of turtles are known to use magnetic cues to determine latitude, it was believed that this wasn't possible for longitude. However, the loggerhead turtles have managed to surprise researchers by developing a method that involves using the strength and angle of the Earth's magnetic field.

Nathan Putman, the lead author of the research, emphasized that "the most difficult part of open-sea navigation is determining longitude or east-west position".

 

"It took human navigators centuries to figure out how to determine longitude on their long-distance voyages."

Loggerhead hatchlings, however, are able to manage this feat as soon as they reach the sea from their nests.

On reaching the sea, the hatchlings are able to establish the correct course to the open ocean. The young loggerheads then spend several years successfully navigating complex migratory routes over thousands of miles of ocean.

To carry out the research loggerhead hatchlings from Florida were placed in circular water containers and tethered to electronic tracking systems to monitor their swimming direction. The hatchlings were then exposed to magnetic fields that replicated the fields they would come across in two locations on the same latitude but different longitude along their migratory route. The turtles reacted to each magnetic field by swimming in the directions that would, in the real location, take them along their circular migratory route. The researchers say this shows that the hatchlings are able to determine longitude-using information from the magnetic field.

Nathan Putman explains that "along the migratory route of loggerheads, nearly all regions are marked by unique combinations of intensity (field strength) and inclination angle (the angle that field lines intersect the surface of the Earth)".

"Thus, turtles can determine longitudinal position by using pairings of intensity and inclination angle as an X, Y coordinate system.”

Nathan Putman’s collogue, Dr Kenneth Lohmann said “This not only solves a long-standing mystery of animal behaviour but may also be useful in sea turtle conservation”

If you want to learn more about Loggerhead (and other) Sea Turtles, stop into Scuba Emporium and ask us about our Sea Turtle Awareness Specialty Program.

Sharks are Showing their Worth Again

Photograph by Antonio Busiello

Off the coast of Honduras the Caribbean Reef sharks are being fed Lionfish in hopes of giving them a taste for the new invasive species. The Lionfish population is growing fast, and until the local predators learn to eat the exotic visitors, the Lionfish will continue to consume the reef’s population of small fish; which are needed to help keep the reef clean and healthy.

Photograph by Antonio Busiello

Unfortunately the oceans shark population is disappearing fast, and if we don’t stop over-fishing them for fins, food, and trophies we may loose there help forever.




If you want to help make a change click on over to Project Aware’s webpage and sign the petition to Help Give Sharks a Fighting Chance.

Thriving 'Middle Light' Reefs Found in Puerto Rico

Lately news about our sea always seems to be about its decline, so it was very exciting to come across a story about a healthy - thriving reef on the NOAA website.

In La Parguera, Puerto Rico scientist found a 12-mile wide Mesophotic (or Middle-Light) Reef. Mesophotic reefs are reefs that grow at the deepest level that light-dependent coral reefs can survive. The Le Parguera reef starts at around 100 feet and is still showing growth as deep as 330 feet.

Little has been known about these Middle-Light reefs, because the technology for scientists to explore at those depths had been so limited. Now however, as the techniques and equipment used in tech diving becomes more available and user friendly for everyone, these reef are beginning to be explored. Check out the beauty of these reefs.

Credit: H. Ruíz

What is really exciting is how groupers, reef sharks, and snappers still thrive on these beautiful reefs. These fish, which were once so common on shallower reefs, can restore the depleted fish stocks once the heath of the shallower reefs, are restored.

So lets get involved and work together to protect these Mesophotic Reefs, as we work to rescue our more popular Shallow Reefs. Check out Project AWARE’s website.  Sign up for one of Scuba Emporium’s ecologically centered diving specialties; like Coral Reef Conservation and Project AWARE. And most importantly keep diving, exploring, and sharing what’s under the surface with your friends and family; so we can continue to remember everything there is to protect, above and below the surface, of this beautiful blue world.