...exactly why do we need this? Shark attacks on kayaks are exceedingly rare.

Brian, I posted this article as a kind of follow-up to another thread of a few weeks ago that got into sharks. I posted some facts about shark attack in that thread. At $240 US and very small and lightweight (one pound) it seems an amazing little device. And I sure do not know of any other way of doing this being available before. For a diver in some conditions it could be a lifesaver. For a swimmer likewise. For a kayaker it is his/her option, but AT LEAST NOW there is THAT option.

: If it's mounted to your ankle, and the shark is REALY hungery, wouldn't this
: get you bit in the head :>
: If they have this technology, someone should check into floating bouys around
: popular swimming areas that sharks are known to frequent. Alot better than
: killing an animal for following it's instincts.

David, the article adresses both issues specifically:

"testing...showed sharks were repelled at about two to three meters (six to nine feet) from a swimmer."

It does seem they are cutting it kinda close for a 6' tall swimmer! The operative words in the article were "...sharks were repelled at about 6 to 9 feet FROM A SWIMMER". A safety "Zone" is therefore created "around" the swimmer by the device. Because it sure would be a shame for the shark bite your head off while the "rest" of you is "protected", ha, ha.. But if a shark is interested that 6 feet FROM YOU could become pretty important in a hurry!

And for your 2nd point the article says it well how this device could help prevent the needless killing of net protection:

"{The Company is} working on electronic shark repellant units which can be used to create a safety zone {....} a larger version for beach protection. "Apart from protecting human lives, the beach protection units would enable the removal of existing net and hooking systems that are responsible for the slaughter of a range of marine life, including protected species such as whales, dolphins, turtles and dugongs,"