Restoration of ecosystems is good except when it's not.
What do you think about putting the dead rotting bodies of salmon into streams with water quality problems caused by excess nutrients? If you're like me, that sounds bad.
So why are smart and earnest conservationists doing it in the Molalla River, which is on Oregon's nutrient-polluted streams list? Because swarms of salmon used to die and rot in streams, so restoration means putting dead salmon bodies in streams where they "should" be. This seems to work in nutrient-limited streams, but a stream with nutrient excess may respond differently.
When salmon streams are healthy, then the rotting bodies feed bugs and fish. When salmon streams are degraded, lacking native species, and already burdened with excess nutrients, then adding more nutrients isn't likely to restore anything.
There's nothing magic about salmon carcasses. They will feed and make more of whatever lives there. It what lives in a stream is algae and non-native fish, then salmon carcasses will only feed the unwelcome guests.
I like the idea of salmon carcasses in streams. But only at the end of a restoration process when habitat is good, native species are present, and the ecosystem is fairly healthy. I'm happy when the rotting bodies are native fish that just spawned after swimming upstream naturally.
But putting salmon in streams to jump-start the process may just worsen existing problems. All things in good time.