 However, unbalanced fishery led to the drastic decrease of catch in 1955–1963, sometimes to 1,600 tonnes per year.Trawling has been forbidden in Lake Ladoga since 1956 and some other restrictions were imposed.The situation gradually recovered, and in 1971–1990 the catch ranged between 4,900 and 6,900 tonnes per year, about the same level as the total catch in 1938.