Larry -
Thanks for sharing all that information!

I have long believed that the sockeye bottleneck is likely at the food competition level for young fry as they leave the Cedar. The native longfin smelt and sticklebacks as well as the young of the year of most other species (think perch) in the lake use the same food resources as the sockeye.

Let's consider the longfin smelt which potentially could be the most competitive. In the late 1980s/early 1990s summer sampling found that the smelt were approximately 5 times more common than juvenile sockeye; likely much higher now. Have seen estimates that place smelt abundances in the millions. The vast majority(905? of the smelt spawn in the lower Cedar (from mid-Feb. to mid April). The fecundity of the smelt has been reported as between 16,000 and 20,000 eggs/female or more than 10 times that of the sockeye. The smelt depending on water temperatures typically hatch in 4 to 6 weeks. As a result there could be a lot of newly hatched smelt entering LW at the same location (mouth of Cedar) as the sockeye in the same time frame (maybe a little earlier) that are looking to consume the same zooplankton. The smelt fry being smaller could be consuming the zooplankton (at a smaller size) before they become available to the sockeye

Something to consider- I'm sure that you have notice that over the years the graphs of the sockeye returns have show a saw-tooth like line with a define even/odd year difference in abundances. Interestedly the smelt in both their abundance and spawn timing show even/odd differences. It would be interesting to see if there is a correlation - smoking gun?

Prey/predator relationships can be tricky but it could be that if indeed the bottle neck is at least in part at the food competition level the current predator control (especially the pelagic ones) maybe counter productive. There are studies where limiting predators on plankton eaters results in increases in plankton eaters - no surprise there! In the simple model of just smelt and cutthroat could it be that removal of cutthroat are resulting in more smelt? More competition for the sockeye?

Curt