Wow, I have never really thought about this questions. A great tidbit for the Science Class. I am learning more about the Arctic Ocean and these pelagic creatures everyday. Jellyfish are not the first critters you think about in the Arctic. But there are a lot of them. The continental shelf is very large off the western coast of Alaska. And Discover Magazine has and article about how these simple creatures may be increasing in number.
There are also some incredible photos in the Nikon Micro photography Gallery at Discover Magazine.