In this article, the author discusses a recent study on Chinook Salmon, and their ability to navigate the globe using the earth's magnetic field, or their "Salmon Positioning System." In 2013, a team of scientists provided evidence of a link between salmon migration patterns and the earth's magnetic field, and this year, scientists seem to have proven this theory. Scientists simulated extreme latitudinal conditions, then they exposed hundreds of "juvenile Chinook Salmon" to these conditions and observed their response.The fish are all from the same hatchery in Oregon. The findings were strange to say the least. The scientists used fish that had never left the hatchery, so as to test the theory that this trait was not learned, but rather, inherited. When the fish were in a magnetic field that was most like the northern seas, they tended to swim in a southern direction, and when they were a field most like the southern seas, they tended to swim north. The fish clearly show a preference to the magnetic field that they are oriented to. The magnetic fields they were presented with were not very strong either, they couldn't even move a needle on a compass, but the salmon could clearly sense it. Now the scientists are not saying that the magnetic field is not the only navigation tool that these fish use, but it is very important to the salmon's yearly migration.
NOS themes:
- Science is based on evidence: The scientists used a large testing group, and multiple tests to effectively prove the theory.
- Role of credibility: The study was funded by Oregon Sea Grant and the Oregon Department of Fish and Wildlife, and will be published by Current Biology.
- Importance of repeatability: The researchers used thousands of fish, and tested multiple directions.
Interesting how the salmon can sense a compass. I would suppose that if the magnetic field was most like the eastern seas that the salmon would swim to the west, and if the magnetic field was most like the western seas, that the salmon would swim east. Right?
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