Lake Superior other Great Lakes fish, populations have also been affected by the accidental or intentional introduction of foreign species such as the sea lamprey and Eurasian ruffe. Accidental introductions have occurred in part by the removal of natural barriers to navigation between the Great Lakes. Overfishing has also been a factor in the decline of fish populations. Lake Superior Lake Superior (; ), the largest of the Great Lakes of North America, is also the world's largest freshwater lake by surface area, and the third largest freshwater lake by volume. The lake is shared by the Canadian province of Ontario to
Yangcheng Lake Yangcheng Lake Yangcheng Lake () is a freshwater lake about northeast of the city of Suzhou in Jiangsu Province, China. It is the most famous area of origin for the Chinese mitten crabs which are considered a delicacy. Yangchen lake is located between Lake Tai and the Yangtze River. It crosses the boundary of the cities Suzhou, Changshu and Kunshan and has a surface area of about . The Chinese mitten crabs migrate from Yangcheng Lake towards the Yangtze delta for mating in September and October. The local fishermen harvest the animals during this migration. In 2002, the total production