Fishnbuck
I would answer the ? With a ? Why keep a post spawn fish? Meat quality is poor. No eggs.
With downrunners, their meat is much less and often not great quality so the thought is, why not give them the chance to run again another year? And leave the biter in the gene pool.
I've never kept a spawned out fish (was just sort of thinking it through in my post above), and I don't plan to, but some possible reasons for others might be:
A) it's a steelhead that looks more or less freshly spawned and still has some meat and you figure it might smoke up OK, B) you suspect that for whatever reason your fighting or handling it might cause it to die anyway, C) because you have it out for all hatchery fish, D) you want to see for yourself what the meat quality is like in that particular fish because someone telling you on an online forum that it will suck isn't enough to satisfy your curiosity, or E) it's a huge monster spawned out steelhead and even though it looks sort of like a giant eel you want to take it home and show it off to yo mama.
Is downhill steel meat like that of a dark salmon then?
not trying to hijack the thread but I learned from my BIL that Washington recently made it mandatory to retain hatchery steelhead on many streams...
2015/2016 WA Regs book:
"Mandatory Hatchery Steelhead Retention - ...an additional measure was made to provide protection to fish stocks in streams where there is concern about hatchery and wild fish spawning together. This measure..requires that anglers keep the hatchery steelhead they catch. To encourage anglers to harvest more hatchery steelhead as the fish arrive back to natal streams/release sites, for many streams the daily limit increases from 2 to 3 hatchery steelhead.
For streams where this rule applies, you will see: Mandatory Hatchery Steelhead Retention directly below the water listing."
I work in fisheries policy and might have the unpopular opinion here, but there should be more mandatory hatchery retention, especially a hatchery downrunner. We are all aware that hatchery fish are generally weaker than native broodstock. A hatchery downrunner is one that didn't hit a fish trap as intended and spawned in the creek, thus proven to be diluting native stock. I feel a lot of the fisheries management community would agree that there's a strong case for removing that fish regardless of its food value.
However, since most systems allow C&R of hatchery fish, what you do with a downrunner is up to you. I'm definitely not going to get on anyone's case for releasing a mushy fish.