My friend Brian Denaro just completed a 17+ mile swim from the Hawaiian island of Kauai to Niihau.
Here's a picture of Brian with the island of Niihau in the distant background.

On the way he and his fellow swimmers encoutered jellyfish, Portugese Man o' War and saw a few sharks swimming around/under them. Thankfully they made it across safe (ie with limbs attached) but they did have some crazy stings and sunburns.
The link in the title will send you to a summary blog post in "The Daily News of Open Water Swimming".
And here's a link to the full 'Swim Report' by one of the four who crossed that day.
http://jenschumacher.com/blog/comments/kauai_to_niihau/
Just thought some of you swimmers would be interested in seeing this.