Jellyfish come in different sizes, shapes and colors – and many of them sting really bad – see examples here. The jellyfish on the left face swimmers in the North Channel; the blue bottles on the right face swimmers in Australia.

Nuala Moore, an open water swimmer, coach and diver, talks about the Lion’s Mane jellyfish that often grown to 2 meters wide with tentacles as long up to 10 meters. “We swam into walls of these on the north coast. Solid walls of Lion’s Mane jellyfish. When there are many, their tentacles become inter-meshed and form a spider’s web. It was walls of these webs that Anne Marie Ward swam through for five hours in the dark. They are often 1-2 meters below the surface of the water, but when the night darkness falls, they tend to rise for the heat. In the day, they sink down more from the sunlight.

If there is a lot of wind, then the tentacles break off and the toxins still remain viable. The sting is as effective [painful] if you swim into the rogue tentacle minus the body. Lots of stings happen without the main body in view. During post-storm swims, it is to be expected that stings will happen despite having visual.”

Diana Nyad will be speaking tonight at the TEDMED conference in San Diego, California in front of a brain trust of scientists, researchers and learned luminaries talking about how “60 is the new 40” – and how jellyfish play a part of that for open water swimmers of any age.

Like canaries in the coalmines, open water swimmers are out there taking the brunt of our changing planet.

Copyright © 2011 by Open Water Source