This is generally not a bad thing, though. From my slight applied linguist background: These fillers are generally used in order to establish that the speaker's turn is not yet done. In a conversational situation, having pauses instead of fillers gives the listeners openings into the conversation to become the speaker.

In presentational speeches, fillers aren't so bad, but long pauses IMO are worse. It's a natural thing to have fillers. If you want to have less, just practice more and be more comfortable with what you're talking about.