I’m so old I can remember writing about when two barristers from Canada said that the beaver in South America had grown abnormally large and (with no natural predators) had evolved to eat fish. I’ve been hearing people lie about the kidnapped beaver devastating the land by eating all the trees for more years than I can count on both my hands. Surely we all know they should never have been there to begin with. But I’ve been a little outraged to read over and over how entirely awful and difficult to eliminate they are.
So there is only one video that truly expresses how I felt when I read this particular headline.
Beavers appear to help the growth of brown trout in South America, study finds
CORVALLIS, Ore. – In the early 1900s, brown trout and rainbow trout were introduced to southern South America for recreational fishing and early aquaculture initiatives. About 40 years later, American beaver were introduced in the same region to develop a felt industry.
That history intrigued Ivan Arismendi, an aquatic ecologist at Oregon State University. He is originally from Chile but since 2007 has lived in Oregon, where the beaver is the official state animal and the mascot of the university that employs him. He wondered what impact the introduced beaver in Chile had on the health of the introduced brown trout.
Through field work in a remote area of Tierra del Fuego, Chile, Arismendi and his team determined that dam building by the beaver modifies the aquatic environment, providing a wider range of more energy-dense food sources for brown trout. This results in improved growth of the brown trout, they concluded.
Well, of COURSE they do. Of course they do. And hey I be those invasive fish aren’t the only thing that eat all those new water bugs. And gosh I bet having more fish to eat is pretty darned good news to all those cayman and heron and penguins or whatever else eats fish in South America.
They determined growth rates by measuring the scales of the trout, which, like tree rings, can be used to determine how much the fish are growing. They determined their diets by studying the food sources that were available at the field sites, and the contents in the stomachs of the fish.
They found that the growth rate of brown trout found in streams where beaver were present was 14% higher than in streams where beaver were not present.
“What we see in these invaded environments is totally coherent and similar to what we see between beaver and salmonids in the Pacific Northwest,” Arismendi said.
Well of course it was. That’ what you get when a student born in Chile immigrates to Oregon for college. People who can see the forest for the trees. I think we love Ivan Arismendi with all of our collective heats now. Maybe we should send a care package?
