In the Baltic Sea Germany choose another strategy of naval operations.Rather than destroying the Soviet Baltic Fleet they choose to blockade it.To achieve this they layed mines all along the Gulf of Finland.This would prevent the Soviet Baltic Fleet from attacking German ore convoys coming from Sweden.However mines alone weren't enought to contain the Soviet Baltic Fleet due to the fact that the Soviet Navy would use mine clearing ships to clear the lanes.Using this kind of ships the Soviets evacuated Talinin,however they took heavy casualties,loosing some of the transports and light ships,but the big soviet ships managed to get away.Soviet submarines conducted patrolling missions in the Baltic and managed to sunk some german transports.This lead to more mines being laid along the gulf of Finland.Submarines were also used to bring supplies to the besieged city of Leningrad and take out of the city wounded soldiers.To prevent the Soviet submarines from breaking the blockade an anti submarine net was layed along the Gulf of Finland.The net streched from Talinin to Helsinki and was made of reinforced steel.It proved to be impossible to break.The Soviets tried to bomb the net by air,submarines tried to torpedo it and also crashed with it in the hopes of destroying it but nothing worked.It wasn't until 1944 when Finland signed the armistice that the blockade was broken and the Baltic Fleet was free to operate again.In the North sea soviet Naval Fleet had the mission of protecting Land Lease convoys coming from Great Britain.Their objective was intercepting German heavy ships sent to destroy Land Lease convoys.However they only achieved small victories.They were very active during the 1944-1945 period during which they sunk several German transport ships evacuating civilians and troops from Konigsberg.So to conclude,Luftwaffe air superiority,mines,costal batteries and the anti shipping net were all factors that inflicted heavy losses to the Soviet Baltic Fleet.