Thanks for the tips and pointers and encouragements. Found the hard data I need here:
http://www.wlf.louisiana.gov/sites/d...ent-report.pdf
and
http://www.wlf.louisiana.gov/sites/d...assessment.pdf
These are the official state oyster stock assessments.
The graph below shows the decline in oysters on the east side of Calcasieu Lake (Area 29).