Salmon inherit mental map based on Earth's magnetic field

Friday, February 21, 2014 by: L.J. Devon, Staff Writer
Tags: salmon, magnetic field, mental map

(NaturalNews) At the Oregon Hatchery Research Center, a team of scientists set out to learn how Chinook salmon migrate and how they return home from the vast depths of the ocean. It's fascinating how salmon navigate thousands of miles of open sea and ultimately return to their river of origin.

Magnetic field experiments show that salmon have a mental map that leads them home

Ultimately, the researchers discovered a pattern in salmon swimming direction that was related to the earth's magnetic field. They basically found that salmon inherit a mental map based on the earth's magnetic field that guides them through migration and on their journey home.

The researchers put hundreds of young Chinook salmon to the test, examining the effect of various magnetic fields on the swimming patterns of the fish. The salmon, responding to the experiment, which included "simulated magnetic displacements," would basically swim in the direction that brought them together in the center of their marine feeding grounds.

The researchers placed young, 2-inch-long fish in 5-gallon buckets filled with water and surrounded the buckets with a platform of copper wires that ran horizontally and vertically around the perimeter. After running electrical current through the wires, the scientists created a magnetic field that they could control in intensity and inclination. The scientists monitored the salmon's swimming patterns and documented the direction in which they swam, taking pictures.

The fish's mental map is inherent

The salmon that were exposed to a magnetic field similar to the northern limits of the oceanic range turned south and began swimming. Fish encountering a far southern field looked to the north and began to swim. The magnetic fields help the fish mentally determine where they are, enabling them to find their way home. It's kind of like an invisible vibration that the fish are sensitive to. It's like fish have a homing device, a mental map that helps them locate their position, so they can migrate and survive appropriately. It's like a designed order within the universe and under the ocean that is traced to magnetic fields in the earth. And this behavior is born within the fish.

"What is particularly exciting about these experiments is that the fish we tested had never left the hatchery and thus we know that their responses were not learned or based on experience, but rather they were inherited," said Nathan Putman, a postdoctoral researcher at Oregon State University (OSU) and lead author of the study. "These fish are programmed to know what to do before they ever reach the ocean."

"The evidence is irrefutable," said co-author David Noakes of OSU, senior scientist at the Oregon Hatchery. "I tell people: The fish can detect and respond to the Earth's magnetic field. There can be no doubt of that."

The fish responded naturally after exposure to magnetic fields that lasted only eight minutes.

The authors of the study make note that eight minutes wasn't long enough to make every single one of the 1,000-plus salmon swim in the same direction, but there was a clear preference. Furthermore, the researchers oriented the salmon randomly, and by nature, the fish figured which direction was "wrong " for them and which direction was "right." The change in magnetic field was their guide.

Putnam relayed how sensitive the salmon really are, putting the experiment in perspective: "What is really surprising is that these fish were only exposed to the magnetic field we created for about eight minutes. And the field was not even strong enough to deflect a compass needle."

Man-made structures may influence salmon's swimming patterns

Putnam pointed out that Earth's magnetic field is relatively weak. The fish's sensitivity to the earth's magnetic field may be interrupted by man-made structures that contain electrical wires or reinforcing iron. These may redirect or affect the orientation of the fish early in life.

"Fish are raised in hatcheries where there are electrical and magnetic influences," Noakes said, "and some will encounter electrical fields while passing through power dams. When they reach the ocean, they may swim by structures or cables that could interfere with navigation. Do these have an impact? We don't yet know."

The fish's magnetic mental map is especially important in their younger years. A wrong turn in the ocean could lead them to starvation. Efficient navigation by the earth's magnetic field is the grand design behind the survival, migration and "mental map" of the fish.

Sources for this article include:

http://www.eurekalert.org

http://www.eurekalert.org

http://science.naturalnews.com