Industrial ports and harbors concentrate shipping and other industrial activities in river mouths and embayments, with associated increased risk of physical habitat disturbance and pollution. Shipping within the Great Lakes involves as much as 200 million tons of cargo at more than 100 ports; primary cargos include iron ore, coal, limestone and grain.
Mapping industrial ports and harbors as a Great Lakes stressor
We mapped the average number of annual ship arrivals at Great Lakes ports from 2007-2009.1
The most highly visited ports in this analysis include Duluth-Superior (MN-WI), Hamilton (ON), Toledo (OH), and Cleveland (OH). Because the impacts of port and harbor locations likely are restricted to the port vicinity, we assumed their influence decayed to 10% of effect within 2.5 km and was negligible at 5 km.
Spatial distribution of industrial ports and harbors as a stressor in the Laurentian Great Lakes. (Inset: Western Lake Superior).