If you really want to see the 2019 Susquehanna SMB report, just request a copy.
As for the lower portion of the middle Susquehanna R Rock Bass and Redbreast Sunfish population decline, my distinguished contact told me that the population decline became evident sometime in the 1950’s.
A review of PFBC biological data from the lower river (York Haven Dam to the Conowingo pool ) during the period of the late 1970’s through the early 2000’s did not show that there was an abundance of these species; they were sparse at that time.
A more recent and substantial decline in in at least a portion of the lower Delaware R. RBSF population (non-tidal area in Bucks Co) occurred sometime after the 1980’s, apparently in the 1990’s. Strong evidence for this was seen at the Point Pleasant sampling site.
They are fairly abundant in a number of lower Susquehanna R tributaries and most other SE Pa warmwater streams. You can see some of that info in the Area 6 biologist reports on warmwater streams from across the region.
As for the Schuylkill SMB population, its decline, as I have said before, preceded the introduction of Flathead Catfish. Sedimentation related habitat degradation was obvious from Gibralter downstream and especially from Linfield area downstream. The first observation of former SMB habitat destruction through inundation by sand was on the Norristown pool in the 1980’s.
Finally, as Dave stated, lower Susquehanna Walleye populations have long varied with year class strength. Big year classes, which occur every few years, pretty much drive the quality of the fisheries three and four years later. A general observation of mine over many years has been that each 3-4 years includes a very large year class, a moderate year class, and a poor year class. The year class in what I will call the fourth year, but which could occur anytime during the four year period, would be a repeat of one of the other three year class sizes. I have never seen an extended walleye reproduction “problem” in the river.
