A new research showed that exposure to iron pipes and steel rebar affects the navigation abilities of fish.
Nathan Putman, lead author and a postdoctoral researcher from the OSU College of Agricultural Sciences' Department of Fisheries and Wildlife, along with his colleagues from Oregon State University, presented empirical evidence documenting the correlation between the migration patterns of the salmon to the changes in the planet's magnetic field. Earlier this year, a team of researchers from the Oregon Hatchery Research Center confirmed that salmons use magnetic maps to guide them during migration.
The researchers concluded that exposure to iron and steel materials affect the fish's ability to use these magnetic maps and, therefore, affect their navigation. Based on their observation, the steelhead trout which were exposed to such materials, which are common parts of hatcheries, developed a poor sense of navigation because their magnetic "map sense" was affected by the metals surrounding them. The team studied the fish at the Oregon Hatchery Research Center in the Alsea River basin in 2013.
"The better fish navigate, the higher their survival rate," Putman said in a press release. "When their magnetic field is altered, the fish get confused."
Putman explained that there were some differences in hatchery construction that explained why some fish that grew up in a hatchery survived well when released into the wild. He recommended the use of other materials and alternative structures in hatchery construction to stabilize and improve the magnetic field around the hatchery.
"It's not a hopeless problem," he added. "You can fix these kinds of things. Retrofitting hatcheries with non-magnetic materials might be worth doing if it leads to making better fish."
Earlier research showed that fish use magnetic maps by swimming to where marine feeding grounds are abundant. Putman's research and previous research showed that fish do possess magnetic field maps which they use to find food.
More details about this study were published in the June 7 issue of Biology Letters.
