ERICK BENGEL: Scientists are seeing way more invasive walleye in the Snake River. That could mean trouble for salmon. NWPB’s senior environmental correspondent Courtney Flatt explains.

COURTNEY FLATT: A new study shows Snake River walleye could actually be helped out by other invasive fish. Those fish are likely altering the food web. The phenomenon is called the invasional meltdown hypothesis. 

Basically, researchers found that walleye snack on salmon and steelhead in the spring. When that migration is over, walleye mostly eat American shad. That’s another invasive fish found in the Snake River. 

Jonny Armstrong is with Oregon State University. He says the shad aren’t providing a buffer for salmon. Instead:

ARMSTRONG: “They’re providing this unique foraging opportunity at a different time of year.  And populations of walleye are likely supported by other invasive species.”

FLATT: Anecdotally, Armstrong says where there’s shad, walleye are booming. In places where shad aren’t around, there are fewer walleye.

I’m Courtney Flatt.