Mike G. - Interesting suggestion. Create two seperate ESU's and list the wild one but not the hatchery one. It would probably serve the same purpose as listing both and doing a 4(d) rule.

However, the catch is whether there is sufficient biological basis for the distinction. Hatchery fish and wild fish are virtually identical, right down to their DNA. They even live in the same habitat and spawn at about the same time. The differences are related to behavior and survival, both in freshwater and salt. So are these differences sufficient to allow NMFS to list one but not the other thru an ESU? Clearly, the differences are sufficient enough to affect the returns of adults. Witness the large number of hatchery adults vs. the number of wild adults returning to spawn. But are they sufficient enough to warrant different listing decisions?

Unfortunately, it really isn't that clear. There's probably enough ambiguity in the data to allow the decision to be driven more by political consideration than by biological facts. But if there is enough information to justify different listing decisons, it might be a good position to take.