I just walk close to the fruit beetles on the trees and chase the hoppers and crawlers away. If it slows down, I take a little swim and it seems to pick right back up again. What I do notice is that I seem to get a lot more of the Dynastid Beatles.
Often, I get another shark fin when I do this. Yesterday, every time I took a swim, I caught another shark--sometimes I had to swim around the shark to get to shore.