It's a question I've found myself asking over and over. Charlie and I call these jumping carp clown carp because they are reminding of a circus clown doing somersaults and acrobatics.
For quite sometime it's been my belief that these carp jump in order to cleanse their skin, fins, or some part of their body.
Jim Burns over at LA River Fly Fishing has now asked the question and even put a poll up to get other opinions from the fly fishing for carp community.
Visit the LA River Fly Fishing blog and participate in the poll... it will interesting to see the answers.