Interesting data.
What this doesn't account for, outside of natural recruitment like you mentioned, is the increase in angler pressure. Stocking figures have remained pretty static, with some fluctuation since 2016, but in my anecdotal experience, fishing pressure has doubled during that same time period.
If fisherman are successful, and taking home more fish, which I believe they are due to Facebook big-mouths trying to sell their dodgers and squids, there are fewer fish all around, and fewer to spawn. Compound that with years of drought during the same time period, and you have a fishery in decline.
What this doesn't account for, outside of natural recruitment like you mentioned, is the increase in angler pressure. Stocking figures have remained pretty static, with some fluctuation since 2016, but in my anecdotal experience, fishing pressure has doubled during that same time period.
If fisherman are successful, and taking home more fish, which I believe they are due to Facebook big-mouths trying to sell their dodgers and squids, there are fewer fish all around, and fewer to spawn. Compound that with years of drought during the same time period, and you have a fishery in decline.