ene.gov.on.ca/environment/en/resources/collection/data_downloads/index.htm), and Environment Canada (access date 10 July 2012, http://www.ec.gc.ca/inrp-npri/default.asp?lang=en&n=F8D54254-1). There is a gap in scientific knowledge from about 1900 to 1972 regarding the ecological condition of Lake St. Clair as noted in earlier studies of Leach (1972) and Monheimer (1975). Nutrient concentration data (from 1998 to 2008) were collected near the mouth of St. Clair River (station 740016, 42.6494°N, − 82.5133°W) by the Michigan Department of Environmental Quality. Ecological data were gathered

from peer-reviewed literature and from state and federal agency reports with some sources providing electronic check details data (Bell, 1980, Cavaletto et al., 2003, David et al., 2009, Hiltunen, 1971, Leach, 1972, Michigan Department of Natural Resources, 1981, Michigan Water Resources Commission, 1973, Monheimer, 1975, Nalepa and

Gauvin, 1988, Nalepa et al., 1996, Reighard, 1894 and Upper Great Lakes Connecting Channel Management Committee, 1988). These data were chosen because the sites were located near the middle of the lake (see S1) and provide estimates of the changes in the native mussel VX770 species richness, total phosphorus concentrations, chlorophyll a concentrations, and transparency depth (via Secchi disk depth) which are useful indicators of the water quality condition IMP dehydrogenase of the lake over time. Commercial fish harvest data (thousands

of pounds converted to kilograms) were found online from Baldwin et al. (2009) (access date 18 December 2012, http://www.glfc.org/databases/commercial/commerc.php) and the available grand totals (USA + Canada) were used. Historic typhoid fever statistics were found online through the state’s website on vital statistics (Michigan Department of Community Health, access date 2 April 2012 http://www.michigan.gov/mdch/0,4612,7-132-2944_4669—,00.html). Historically, key beaches and other water bodies along the western lakeshore were monitored for bacterial indicators (which are found in the intestines of all warm blooded animals) in swimmable waters by Macomb County Health Department to protect human health. These historic beach data were digitized and analyzed based on records from the Macomb County Health Department (1948–1998) and more recent data were downloaded from the Michigan Beach Guard online database (http://www.deq.state.mi.us/beach/). Beach violation standards have changed overtime from single sample standards of 5000 CFU/100 mL for total coliform (prior to 1981), to geometric mean 400 CFU/100 mL for fecal coliform (1981 to 1996) and then to a daily geometric mean of 300 CFU/100 mL and a monthly geometric mean of 130 CFU/100 mL for Escherichia coli (1996 to current). Because indicators and sampling methods have changed over time, data were normalized to E.