Casiguran in Aurora Province is home to the Kasiguranin. Their language is 82% mutually intelligible with Paranan, a language in eastern Isabela, probably because Aurora and Isabela lie in close proximity.
The Kasiguranin rely mainly on fishing and farming, as do other groups in Casiguran.
Lewis, M. Paul (ed.), 2009. Ethnologue: Languages of the World, Sixteenth edition. Dallas, Tex.: SIL International, http://www.ethnologue.com/
Casiguran, Aurora: Undiscovered Paradise. http://casiguran-aurora.blogspot.com/