I vote boogy boarders at the BOTTOM!!!!
With my two water sports of surfing and kitesurfing they have (for both) been the most annoying group of users IN the water.
Be out on the water around 3.30 on a nice bank to yourself either surfing or kitesurfing and watch the swarms of grommet boogs running down the beach, then swarm towards you and frenzy for every wave to destroy your sesh [}:)]
The sheer numbers of these pests show they are ripe for culling and are quite clearly at the fat end of the pyramid. That, and it is also by far the easiest of the sports to master....man, that close-out barrel roll on every wave is so exciting

I do however accept that this is a fine sport for ladies to adopt and grace us with their presence in the lineup