In an 8 vs 8 base game 2 sharks is recommended but not required. You can win with 1 shark but everyone has to do their jobs very well.
Strategies:When sharking in base, your main purpose is to use all yours reps and die. Getting a few kills here and there is your second objective. Dieing with reps is something I call dieing prematurely and should never happen.
When attacking base first rep for the spiders (spids) trying to clear lower. Then push your way up to entrance and rep for your team. If your team mates die you have no pushing power. Watch for javelin (jav) bombs and warbird (wb) bullets. Unless you have a jav on your team, use a mine to take out the jav or wb shooting through the holes in lower entrance. Also look for chances to throw a mine up entrance. This is risky but possible and some sharks don’t expect it.