1. Objectives Determine changes in density and biomass of dreissenid population since 1991-1996. Determine changes in density, biomass, and species composition of the benthic macroinvertebrate community since 1987-1996.

2. Dive Sites Ponar Sites 2008 (F) 2009 (F) 2010 (F) 2006 (F) 2007 (S,S,F) 2008 (S,S,F) 2009 (F) Site-D Site-P

3. Mean (± SE) Density (no./m 2 ) and AFDW Biomass (g/m 2 ) of Dreissena in Saginaw Bay Site-D: 7,693 ± 414 Site-P: 1,511

4. Mean of All Inner Bay Dive Sites (n=5) Site-D: 87.7 92.4 Site-P: 99.3 3.3

5. Year St. 4 St. 7 St.10 19917010 199201210 19937550 199456014 1995022 19960110 20060210 2007106033 200803770 200903000 Dreissenid Density (No./m 2 ) at Sites with Soft Bottom (Silt)

6. Site Density% < 5mm St. 56,144 97.4 St. 6223 48.8 St. 13442 85.9 St. 143,510 97.0 St. 15500 85.9 St. 16391 53.3 St.- D7,277 90.9 St.- P1,511 3.3 Density (No./m 2 ) of Dreissenids and Percentage of Small Individuals (< 5 mm) at all Dive Sites

7. Why is the dreissenid population lower in 2008-2010 compared to 1991-1996? 1)Goby predation 2)Near-bottom conditions unsuitable

8. Credit: N. Hawley

9. Credit: D. Kashian St. 5 - Inner Saginaw Bay

10. Future Work Determine length-weight regression for dreissenids collected in 2010 Complete analysis of benthic macroinvertebrates and write manuscript