The Christmas Island guys nail these within sight of the reef on the North shore pretty regularly - nobody was targetting them on flies though - the guides wanted as many lines trolling as possible - deep water trips are meat trips out there!
When I was there last year the guides came in most evenings with Wahoo in the 60 - 70lb class - defeinite world record fly prospects for anyone with the time and $$$ to soend. Awesome fish and one of the fastest in the ocean!
The yellowfin were pretty impressive too.
When sight fishing, look over your shoulder from time to time, you never know who's behind you