Piracy under the principate and the ideology of imperial eradication

In his Res Gestae, Augustus boasts:

I made the sea peaceful and freed it from pirates (mare pacavi a praedonibus). In that war I captured about 30,000 slaves who had escaped from their masters and taken up arms against the republic, and I handed them over to their masters for punishment.

(Res Gestae, 25. 1, trans. P. Brunt and J. M. Moore)