Sharks can be anywhere just look what happened in the "true" story Sharknado.
.....most spearing beach locations have varying levels of currents so best to do your homework about an area, pick the right day, have a dive buddy or even better go with somebody that knows the area and have proper safety equipment (float, flag, etc)
. As for Inverloch having extreme currents maybe in the inlet but you can't spearfish in there.
.....not many places to spearfish in Inverloch. You can only spearfish in smallish area between Anderson's Inlet and Bunarong marine park. I think it's an area called Flat Rocks.
Your closest spots are Cape Paterson "Swimming beach" (not surf beach) small bay left of the big rock pool but again pick the right day as current can be strong as you get 100m+ off the beach. Harmers Haven then Kilcunda are other spots but are more open to the ocean so best to dive when you get more experience.
As for Phillip Island
Sunderland Bay can be a good beginners spot but out wide the current can be quite strong especially with the out going tide.
Someone else more experienced may give you more info regarding PI (Phillip Island) locations such as YCW, Cat bay, Kitty Miller, etc