Hi, Zim,
I live on Alsea Bay and fish for SRC's every day, although most days I don't hook any. In fact, it's been more than a month since I released my last one. In years past, there have been SRC's to catch in the estuary at this time of year, but so far the fish seem to be elsewhere. I'm hoping things will pick up soon.
It's surprising to me that the're aren't more SRC's around, since the Bay is full of fall Chinook smolts, much to the delight of the cormorants and Caspian terns.
At one time, Alsea Bay was renowned for its 'blueback" fishery, but no more. A couple of seasons ago, the Bay was closed to the taking of SRC's, although I can find nothing in this year's regulations prohibiting their capture. I don't really know of any agency effort to monitor the popluation dynamics of sea-run cutthroat in the Alsea river system or estuary. My strictly unscientific observation is that the popultion is in decline.
I've caught SRC's from Clemens Park on down, but, as I said, most of my fishing is done in the lower estuary. Alsea Bay SRC's respond to a wide variety of flies, but, one of the most consistent has been John Shewey's "Alsea Special", which resembels a sand shrimp, at least in color combination. Another very good fly is the "Burlap Charlie" tied with an orange beard.
Alsea Special:
Hook: barbless No. 8 - No. 4 2x long
Tag: Silver
Tail: Pale Yellow and pale pink hackle fibers, mixed.
Rib: Silver embossed tinsel
Body: Yellow seal
Collar: Red and yellow hackles, mixed
Wing: White polar bear
Head: Black
Burlap Charlie
Hook: ring eye 1x stout
Rear 1/3 of body: Gold oval tinsel
Front 2/3: burlap picked out a bit to look fuzzy
Eyes: brass bead chain
Beard: orange calf-tail
One more thing: I notice you're from Corvallis and so probably fish pretty high up in the river. The SRC's will follow the salmon, as you point out, looking to snatch the occasional egg from a ripe fish. Consequently, egg patterns work very well when the Chinook are around.
Steelhead flies in small sizes work, too.
Cheers,
Eric