I also don't get your first question.
But the body fat percentage varies massively from surfer to surfer.
You need to be more specific about 'surfer' tho, cos there those who surf once a year and those who get in most days and they are all surfers.
If you compare surfers to atheletes - say 100m sprinters for instance, I'd say that sprinters have less body fat cos not many people call themselves 'sprinters' who only do it once a year, in fact I'd say anyone who calls themselves a sprinter probs does it several times every week so they are gonna be very lean (...er I spose, actually I'm just totally guessing and don't really know anything about sprinters

).
But the top pro surfers, from what I've seen all seem to look like they have pretty lean athletic builds, I guess due to the fact most the time surfing is purely aerobic exercise

.