 Between 1820 and 1865, the state of Maryland banned the practice of dredging for oysters.In the latter year, the law was relaxed; the use of steam power remained banned, however, and remained entirely prohibited until 1965, in which year powered dredging was allowed two days of the week.As long as dredging for oysters in the Chesapeake was prohibited, oystermen working from log canoes tonged for oysters.