I hope +Mark Limb
doesn't mind, I felt the best way to explain the crop was to show it, so I dropped his original into lightroom and experimented. This is the crop I liked best. It removed that bottom band of sand that I didn't think added to the image, and that puts more of an emphasis on those light yellow bands at the bottom (I did that from lower right corner, preserving aspect ratio). Then from top right I pulled in until it felt right and the fisherman started to intersect the lower left third intersection, while still keeping enough of the surf as I could.
I did a couple of other things to this just to see how I liked them: raised the whites and highlights a bit (about +20) and dropped the blacks and shadows (-30, -40 respectively) to intensify the silhouette and increase contrast a bit. I also added a touch of grain to give it just a bit of grit, but working from a jpeg, the overall processing you can do is limited (and I'm unconvinced about the grain, but then I'm always unconvinced about grain. Still, this is the kind of image I'd experiment with it on).
I looked at it both with color, and as a b/w conversion. I decided I really liked it with the colors in it, especially with taht one fisherman with the yellow jacket. I think that's a fun surprise for the eye and helps the eye find and focus on looking at the fisherman, and you lose it in a b/w conversion. I also really liked those yellow bands in the sand at the bottom, it gives the image some personality.
So this is my quick thought on the direction I'd take the image. It's definitely not the only way to go, but it might give you a few ideas to play with.