This has been a dome scratcher for quite a while now and it's not just the Kalama. The Cowlitz and Lewis aren't a whole helluva lot better with their return rates many years. Aren't spring chinook a non-native stock in the Kalama? I'm pretty sure that's the case(I think) and if so, it could be as simple as poorly adapted genetics from wherever the stock originated. Along the same line, it could also be a burned out/dulled genetic robustness (producing a less-hardy fish) from too many years of selective hatchery spawning......not enough variation like you'd find in a true wild stock.

Whatever the case, there are no Columbia dams to contend with and the fish are just an earshot from the ocean. Puzzling too is that the Willamette basin fish seem to return better just across the Big C.