As has been mentioned before here, given the huge number of fishing vessels in those waters every night of any given week, I find it hard to believe that someone (quite a few 'someones' in fact) didn't se or hear something if the aircraft crashed in the immediate area.
I would imagine that part of the SAR effort would be patrol boats going from fishing boat to fishing boat - (and I'm not exaggerating when I say that that could take *** weeks, if not months) - asking if the fishermen saw or heard anything unusual on the night in question.