Featured Research

from universities, journals, and other organizations

Pacific salmon inherit magnetic sense of direction

Date:
February 6, 2014
Source:
Oregon State University
Summary:
A team of scientists last year presented evidence of a correlation between the migration patterns of ocean salmon and Earth's magnetic field, suggesting it may help explain how the fish can navigate across thousands of miles of water to find their river of origin. This week, scientists confirmed the connection between salmon and the magnetic field.

A new study using small Chinook salmon "parr" found the fish use the Earth's magnetic field to orient themselves.
Credit: Tom Quinn and Richard Bell

A team of scientists last year presented evidence of a correlation between the migration patterns of ocean salmon and Earth's magnetic field, suggesting it may help explain how the fish can navigate across thousands of miles of water to find their river of origin.

This week, scientists confirmed the connection between salmon and the magnetic field following a series of experiments at the Oregon Hatchery Research Center in the Alsea River basin. Researchers exposed hundreds of juvenile Chinook salmon to different magnetic fields that exist at the latitudinal extremes of their oceanic range. Fish responded to these "simulated magnetic displacements" by swimming in the direction that would bring that toward the center of their marine feeding grounds.

The study, which was funded by Oregon Sea Grant and the Oregon Department of Fish and Wildlife, will be published this month in the forthcoming issue of Current Biology.

"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 and lead author on the study.

"These fish are programmed to know what to do before they ever reach the ocean," he added.

To test the hypothesis, the researchers constructed a large platform with copper wires running horizontally and vertically around the perimeter. By running electrical current through the wires, the scientists could create a magnetic field and control the both the intensity and inclination angle of the field. They then placed 2-inch juvenile salmon called "parr" in 5-gallon buckets and, after an acclimation period, monitored and photographed the direction in which they were swimming.

Fish presented with a magnetic field characteristic of the northern limits of the oceanic range of Chinook salmon were more likely to swim in a southerly direction, while fish encountering a far southern field tended to swim north. In essence, fish possess a "map sense" determining where they are and which way to swim based on the magnetic fields they encounter.

"The evidence is irrefutable," said co-author David Noakes of OSU, senior scientist at the Oregon Hatchery Research Center and the 2012 recipient of the American Fisheries Society's Award of Excellence. "I tell people: The fish can detect and respond to the Earth's magnetic field. There can be no doubt of that."

Not all of the more than 1,000 fish swam in the same direction, Putman said. But there was a clear preference by the fish for swimming in the direction away from the magnetic field that was "wrong" for them. Fish that remained in the magnetic field of the testing site -- near Alsea, Ore. -- were randomly oriented, indicating that orientation of fish subjected to magnetic displacements could only be attributable to change in the magnetic field.

"What is really surprising is that these fish were only exposed to the magnetic field we created for about eight minutes," Putman pointed out. "And the field was not even strong enough to deflect a compass needle."

Putman said that salmon must be particularly sensitive because the Earth's magnetic field is relatively weak. Because of that, it may not take much to interfere with their navigational abilities. Many structures contain electrical wires or reinforcing iron that could potentially affect the orientation of fish early in their life cycle, the researchers say.

"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."

Putman said natural disruptions could include chunks of iron in Earth's crust, though "salmon have been dealing with that for thousands of years."

"Juvenile salmon face their highest mortality during the period when the first enter the ocean," Putman said, "because they have to adapt to a saltwater environment, find food, avoid predation, and begin their journey. Anything that makes them navigate less efficiently is a concern because if they take a wrong turn and end up in a barren part of the ocean, they are going to starve."

The magnetic field is likely not the only tool salmon use to navigate, however, Putman noted.

"They likely have a whole suite of navigational aids that help them get where they are going, perhaps including orientation to the sun, sense of smell and others," Putman said.


Story Source:

The above story is based on materials provided by Oregon State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. NathanF. Putman, MichelleM. Scanlan, EricJ. Billman, JosephP. O’Neil, RyanB. Couture, ThomasP. Quinn, KennethJ. Lohmann, DavidL.G. Noakes. An Inherited Magnetic Map Guides Ocean Navigation in Juvenile Pacific Salmon. Current Biology, 2014; DOI: 10.1016/j.cub.2014.01.017

Cite This Page:

Oregon State University. "Pacific salmon inherit magnetic sense of direction." ScienceDaily. ScienceDaily, 6 February 2014. <www.sciencedaily.com/releases/2014/02/140206133648.htm>.
Oregon State University. (2014, February 6). Pacific salmon inherit magnetic sense of direction. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2014/02/140206133648.htm
Oregon State University. "Pacific salmon inherit magnetic sense of direction." ScienceDaily. www.sciencedaily.com/releases/2014/02/140206133648.htm (accessed April 18, 2014).

Share This



More Plants & Animals News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Great British Farmland Boom

The Great British Farmland Boom

Reuters - Business Video Online (Apr. 17, 2014) Britain's troubled Co-operative Group is preparing to cash in on nearly 18,000 acres of farmland in one of the biggest UK land sales in decades. As Ivor Bennett reports, the market timing couldn't be better, with farmland prices soaring over 270 percent in the last 10 years. Video provided by Reuters
Powered by NewsLook.com
Flamingo Frenzy Ahead of Zoo Construction

Flamingo Frenzy Ahead of Zoo Construction

AP (Apr. 17, 2014) With plenty of honking, flapping, and fluttering, more than three dozen Caribbean flamingos at Zoo Miami were rounded up today as the iconic exhibit was closed for renovations. (April 17) Video provided by AP
Powered by NewsLook.com
Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins