Where Did All The Fish Go This Season

DNR Sturgeon Biologist Ryan Koenigs writes:
As promised I have produced a vignette comparing the early season harvest of the 2016 sturgeon spear fishery on Lake Winnebago to those of past seasons, particularly full 16 day seasons that occurred within the last 15 years.  As stated in the vignette, we aren’t plowing new ground here.  Rather, we were in a similar spot just 3 and 4 years ago and I’m sure that we will be here again.  I hope this information sheds some light on factors affecting the reduced harvest from Lake Winnebago this season. 
As I reviewed my files from my first season as the sturgeon biologist (2013) it became clear just how familiar of ground we are on this year.  I actually drafted a vignette about water clarity in 2013, a little different spin on the analysis but similar results.  For posterity, I have attached the vignette from 2013.  We are all aware that clarity is not as good as it was for the last 2 seasons, but the reasons may be unclear to some.  My best hypothesis for this year’s poor water clarity is the large amount of rain that we received in December.  Typically precipitation in December comes in the way of snow, not rain.  This year it was mostly rain, which contributed to large runoff events and non-point source pollution to the Winnebago System.  Further, the lake froze over much later than normal this year which allowed the wind to mix the lake later in the year and left less time for the lake to “settle” out.  These factors are described in more detail in the attached vignette.