Study: Magnetism helps salmon find home river

GRANTS PASS, Ore. — Salmon have long been known to use their sense of smell to find their home river when it comes time to spawn, but how do they get close enough to smell the river?

A new study suggests that, like birds migrating over long distances, salmon use the earth’s magnetic field.

The study published this week in the journal Current Biology looked at 56 years of fisheries data about which route sockeye salmon used when they returned to the Fraser River in British Columbia.

Scientists found that which way the salmon chose to go around Vancouver Island matched natural shifts in the geomagnetic field. When the magnetic field shifted to the north, the fish swam by the north shore of the island. When it shifted to the south, the fish swam by the south side.

By a smaller degree, fish tended to take the northern route when ocean surface temperatures were warmer, presumably because they were trying to stay in colder water, the study found.

“What we think happens is that when salmon leave the river system as juveniles and enter the ocean, they imprint the magnetic field — logging it in as a waypoint,” which they can follow home from their travels around the Pacific Ocean, said lead author Nathan Putman, a researcher at Oregon State University. “That should get them to within (30 to 60 miles) of their own river system and then olfactory cues or some other sense kicks on.”

Peter B. Moyle, professor of fisheries at the University of California at Davis, said the study was convincing and came to a conclusion that scientists have long suspected.

Moyle noted that other fish, including Atlantic Salmon, sharks and tuna, are known to have magnetic particles in their bodies, which could figure in their ability to migrate long distances to return to a specific place. Some sharks, for instance, return to the same underwater mountains, which produce a change in the magnetic field.

“If you have the right equipment in the brain to detect these fields, it’s like having your (own) built-in GPS system,” he said.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

Olivia Vanni / The Herald 
The Mukilteo Lighthouse. Built in 1906, it’s one of the most iconic landmarks in Snohomish County.
The Mukilteo Lighthouse. Built in 1906, it’s one of the most iconic landmarks in Snohomish County. (Olivia Vanni / The Herald)
Mukilteo mayor vetoes council-approved sales tax

The tax would have helped pay for transportation infrastructure, but was also set to give Mukilteo the highest sales tax rate in the state.

Marysville Mayor Jon Nehring gives the state of the city address at the Marysville Civic Center on Wednesday, Jan. 31, 2024, in Marysville, Washington. (Ryan Berry / The Herald)
Marysville council approves interim middle housing law

The council passed the regulations to prevent a state model code from taking effect by default. It expects to approve final rules by October.

x
State audit takes issue with Edmonds COVID grant monitoring

The audit report covered 2023 and is the third since 2020 that found similar issues with COVID-19 recovery grant documentation.

Bothell
Bothell man pleads guilty to sexual abuse of Marysville middle schoolers

The man allegedly sexually assaulted three students in exchange for vapes and edibles in 2022. His sentencing is set for Aug. 29.

Larsen talks proposed Medicaid cuts during Compass Health stop in Everett

Compass Health plans to open its new behavioral health center in August. Nearly all of the nonprofit’s patients rely on Medicaid.

Snohomish County Health Department Director Dennis Worsham on Tuesday, June 11, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
Snohomish County Health Department director tapped as WA health secretary

Dennis Worsham became the first director of the county health department in January 2023. His last day will be July 3.

Logo for news use featuring the municipality of Mukilteo in Snohomish County, Washington. 220118
On second go, Mukilteo City Council votes against sales tax hike

A veto from Mayor Joe Marine forced the council to bring the potential 0.1% sales tax increase back for another vote Monday.

Community members gather for the dedication of the Oso Landslide Memorial following the ten-year remembrance of the slide on Friday, March 22, 2024, at the Oso Landslide Memorial in Oso, Washington. (Ryan Berry / The Herald)
The Daily Herald garners 6 awards from regional journalism competition

The awards recognize the best in journalism from media outlets across Alaska, Idaho, Montana, Oregon and Washington.

Two visitors comb the beach at Kayak Point Regional County Park on Friday, June 14, 2024, in Tulalip, Washington. (Ryan Berry / The Herald)
Nate Nehring and WSU Beach Watchers to host beach cleanup at Kayak Point

Children and families are especially encouraged to attend the event at Kayak Point Regional County Park.

One person dead in single-vehicle fatal crash near Stanwood

A 33-year-old male was found dead at the scene Monday evening with his vehicle partially wrapped around a tree.

Logo for news use featuring Snohomish County, Washington. 220118
Snohomish Regional firefighters respond to nearly 90 calls on the Fourth

While crews stayed busy on Independence Day, it was far more peaceful than other years.

Vehicles travel along Mukilteo Speedway on Sunday, April 21, 2024, in Mukilteo, Washington. (Ryan Berry / The Herald)
Mukilteo approves 84-acre annexation east of Speedway

The annexation of unincorporated land is expected to bring new revenue to the city as it faces budget challenges.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.