Buy the August on the water and read Janet Messino's insider report for the Vineyard. I don't have it here in front of me, but she observes based on her experiences as a taxidermist that bonito and albacore jaws are tooth, with sharp teeth, but the teeth do not go all the way to the corner so it is hard for them to bite off line.
Spanish mackerel on the other hand have teeth that go right into the mouth's corner, where a fly or hook ends up, and thus can bite off mono far easier than bonito.
I neglected to examine the bonito I caught this weekend closely enough to verify this.
L.