salmon question...

Just another curiuousity question...  Salmon out in the ocean are nice and shiny and silver colored.  Salmon spawning ...  aren't.

So what's the timing on the change from ocean to spawning colors?  Does the process start out in the salt and they hit the rivers when it's done, or does the fresh water start the process, or something in between?  How long do they hang out while changing?  Yeah, I know there's going to be lots of variation by species, just wondering.  Never seen anything about this particular bit of life-cycle biology on the Interwebz...

Jim

Kokanee salmon go through a similar spawning change, even though they spend their entire life cycle in fresh water.  In the fall they gain size, their jaw gets longer, and they start turning reddish, but they still taste good.  Here's a kokanee I caught last October, in the early stages of preparing to spawn.



Later in the spawning process they develop a humped back and a hooked jaw.  After they spawn in the late fall, their color gets muddy and mottled looking, their flesh turns a brownish yellow color, and they taste nasty. I catch spawned salmon while ice fishing in the early winter, but by the middle of the winter the spawners have disappeared and presumably died.

For Chinook the color change has a lot to do with how close they are to their final destination and their particular strain. Lower-river fish, or "tules", in the Columbia will start getting dusky when they are still in the ocean whereas the upriver bright fish that are headed for the Snake River or hatcheries in the Mid Columbia will still be very bright when they are passing The Dalles Dam. That color is one of the ways their bodies start transforming from ocean feeding mode into spawning mode. Lots of things happen during this transition. They stop ingesting food and their stomach shrinks to give their reproductive organs room to start getting bigger.  Even the light receptors in their eyes change.

Varis wildly by species, typically the trigger is when the fish encounters some amount of fresh water, again varies wildly thats why you'll encounter fish in spawning colors in estuaries mixed with ocean bright fish.

Chinook turn more as they get ready for spawning, seem to be able to stay bright the longest, also will travel the farthest
Sockeye seem to blush within a couple weeks
Coho seem to blush within a couple weeks as well
Pinks will start turning immediately and are usually black within days
Chums turn within hours even though they can travel a fair distance and a silver chum in a river is a very rare sight.

Chums will often be nasty and zombie like before they hit fresh water.

I've caught chrome chinook offshore in late September.  You never know what will happen with a particular fish, but I'm pretty sure it mostly has to do with genetics and how close it is to it's spawning grounds/hatchery.

Thanks, all.  Sounds like the further north the better as far the Sound goes    And use chums for play time instead of eating time...

Jim