I wasn't aware the Soviets had a submarine let alone fleets of them so I went digging. Not mine, from this site...
Victories and losses of Soviet submarines during WWII • Axis History Forum
Use of Soviet submarines during WWII [according to statistics from 2004]
Soviet submarines sank by torpedos and artillery fire:
I. Pacific Ocean fleet - 4 enemy ships [Japanese] were sank by submarines in 1945: 2 small steamers, 1 cable wessel and 1 seine-netter.
5 Soviet submarines were lost in Pacific during WWII.
II. North fleet - 35 enemy ships [German] were sank in 1941-1944: 20 transports, 7 anti-submarine boats, 5 auxiliary patrol ships, 1 submarine, 1 mine-sweeper, 1 auxiliary ship. In addition 4 transports [19390 brt] were seriously damaged. The most successful year - 1943 [15 ships were sank].
23 Soviet submarines were lost in Arctic during WWII. The worsest year - also 1943 [10 losses].
III. Black Sea fleet - 45 ships [18 German, 2 Italian, 6 Romanian, 3 Bulgarian, 16 neutral Turkish] were sank in 1941-1944: 43 transports + tankers + anding barges. The most successful year - 1943 [17 ships were sank].
28 Soviet submarines wele lost in Black Sea during WWII. The worsest year - 1942 [13 submarines were lost].
IV. Baltic Sea fleet - 48 ships [17 German, 7 Finnish, 1 Danish, 2 Dutch, 11 Norwegian, 10 neutral Swedish] were sank in 1941-1945: 1 submarine, 1 mine-sweeper, 1 patrol ship, 1 training ship, 1 depot ship, 2 tankers, 1 tug, 1 barge, 37 transports, 2 seine-netters. The most successful year - 1942 [22 ships were sank]
45 Soviet submarines wele lost in Baltic during WWII. The worsest year - 1941 [27 submarines were lost].
The success of Soviet submarines was mediocre - USSR used 277 submarines during WWII [165 submarines were in 1939 - the largest world's submarine fleet]. They sank [by torpedos, artillery fire, mines] 191 ships during Winter war, wars with Germany and Japan in all seas - 4 submarines, 3 small destroyers, 11 patrol ships, 9 patrol boats, 2 mine-layers, 6 mine-sweepers, 9 landing barges, 6 military tankers, 6 military transports, 3 depot ships, 2 hospital ship, 1 training ship, 1 cable wessel, 6 tugs, 6 barges, 9 trawler ships, 1 small fishing ship, 86 transports, 2 tankers, 18 motor-sailing ships [172.785 brt total]. This data includes 5 ships were sank during Winter War [2 German, 1 Finnish, 1 Swedish, 1 Estonian].
Soviets achieved rate 1.89 [191 sank ships per 101 lost submarines]. British submarines achieved the ratio 9.29 [632 sank ships per 68 lost submarines], USN submarines achived fantastic ratio 24.15 as they performed in much more favourable conditions in comparison with other navies [1280 sank ships per 53 lost submarines].
Axis forces - Italian submarines had the ratio 1.1; Germans had the ratio 2.69 [2973 sank ships(!) per 1060 lost submarines including sank under capitulation]; Japanese - 1.73.