Now that magnetic fields are thought to be the reason behind a salmon’s unerring ability to return to the river from whence it spawned, similar research finds the same mechanism in Steelhead Trout.
The elation over the discovery is being tempered a bit with further studies, suggesting reinforcing rebar and steel used in a concrete hatchery pen plays havoc with navigational skills of both species of Parr, and might be making “migrationally challenged” salmonids.
“I would not go out and tell hatchery managers to pull out all the iron pipes and replace them with PVC or aluminum,” said lead author Nathan Putman, a researcher at Oregon State University at the time of the study who is now at NOAA Fisheries Service in Miami working on fish migration questions. “We know it has an effect. What is not clear is whether the fish can recalibrate their magnetic sense after leaving the hatchery, or whether they are confused for the rest of their lives.”
– ABC News Study: Hatcheries Can Disrupt Steelhead Navigation
Migration skills being synonymous with survival, suggests some scientists may be a bit red faced knowing they’ve been pouring hundreds of thousands of juveniles into ponds containing submerged Toyotas and the debris field associated with decades of lost fishing tackle.
Naturally, we’re going to share the blame with the architects, as it’ll be all the lures we lost as kids that are preventing a long overdue resurgence in salmonid returnees.
… and because YOU insisted they were the penultimate game fish (note my Brownlining sense of moral outrage) we can neither put our feet in the creek NOR use anything but plastic fish hooks and weightless everything.
It’s a novel approach, the California Department of Fish and Game drove this year’s salmon smolts to San Pablo Bay bypassing their normal migration. It’s fitting, we take party boats and get seasick, it’s fair they get a little motion sickness compliments of stop and go traffic.