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New study shows Atlantic salmon use the Earth's magnetic field as a navigational tool – much like its cousins, the Pacific salmon – and does not lose this ability after several generations of fish, even after transplanting to a landlocked country . Lake.
The results suggest that Atlantic salmon, which are widely used in aquaculture, may have greater potential for navigation and thus invade new habitats as they escaped from their pens, the researchers explained.
The results of the study are published this week in the journal Proceedings of the National Academy of Sciences.
For the first time, scientists have shown that another kind of salmon uses the magnetic field as a navigational chart. A landmark study conducted by Oregon State University researchers in 2014 shows that chinook salmon use the magnetic field to orient themselves as they migrate hundreds or even thousands of kilometers into the Pacific Ocean to target their areas. ocean feed.
The researchers built a test device at Oregon Hatchery's research center with several "arenas" surrounded by wooden reels wrapped in a copper wire to mimic the Earth's magnetic field. They also tested 1,150 juvenile Atlantic salmon transported from Lake Hosmer, Oregon.
Atlantic salmon were first introduced into the landlocked lake from Maine about 60 years ago, and researchers were curious to know if they had similar navigation capabilities to those of the Oceanic salmon, according to the main author, Michelle Scanlan, research assistant in the OSU faculty. College of Agricultural Sciences and lead author of the PNAS article.
"We wanted to see how Atlantic salmon would react if we put them in different magnetic fields at the boundaries of the Pacific salmon ocean channel," Scanlan said. "If we put them in an extreme north field, would they be correct and aligned in a southerly direction, and vice versa?" And the answer was yes, they clearly lined up in the tank to adapt to a field. magnetic field signal appropriate. "
This ability to use the magnetic field to navigate between landlocked Atlantic salmon is of particular concern because of an incident that occurred in August 2017, when 200,000 to 300,000 Atlantic salmon escaped from a paddock. aquaculture located in Puget Sound, Washington State. Eight months later, one of the fish would have been captured 40 miles upstream of the Skagit River, raising concerns about the impact on native salmon and the ecosystem.
The state of Washington has since banned salmon farms from the Atlantic.
The study also raises interesting questions about how long fish in general, and salmon in particular, retain skills they no longer need, said Nathan Putman, senior scientist at LGL Ecological Research. Associates in Bryan, Texas, who led the 2014 edition of Pacific Salmon Navigation. to study as a postdoctoral fellow at OSU.
"Why did not Hosmer Lake fish lose their ability to navigate?" Putman said. "This is apparently not a skill to use or lose." It is possible that they have smaller-scale navigation tools for use in a lake. Fish are facing spatial tasks that could take advantage of the use of magnetic signals – from moving in a straight line to maneuvering in the water column.Additional research is needed to answer these questions. "
A study of the same researchers published in February in Biology Letters revealed that salmon larvae use the magnetic field when they emerge from "nests" or in the water column – suggesting that salmon have fine-scale magnetic tools that may not have been used. fully identified.
However, on a large scale, the use of the magnetic field partly explains how salmon can find the path to their original river.
"The magnetic field is a bit like you have a GPS system in your car," said Amanda Pollock, a graduate student at the USO Department of Fisheries and Wildlife and co-authored author of the study. "It brings them closer to their river, then their olfactory senses are manifested."
And this ability is preserved even through several generations of landlocked individuals.
The main scientist of the project is David Noakes, professor at the Department of Fisheries and Wildlife of OSU.
Source of the story:
Material provided by State University of Oregon. Original written by Mark Floyd. Note: Content can be changed for style and length.
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