I could do a thesis paper on seasickness AKA ‘Mal de Mer’ & while hardly fatal the symptoms such as nausea, stomach cramps and vomiting, it can put a damper on your diving. It can be hazardous for divers as the dehydration after vomiting increases your risk of decompression illness so it is important to keep up the fluids. I normally feel better once in the water & my SAC normally allows me to be first in & last out. I have been known to feed the fish through the regulator as well. That takes a special knack and an understanding dive buddy as it will surely test your octo as you swish about the primary getting rid of all the fish food. On the other hand it’s a great photo opportunity. There are many articles on the web but remember its never wrong to say your not going to dive if you don’t feel up to it & I have done this a few times because of Mal de Mer. I wish you all the best and hope this helps. For more information see: http://www.ehow.com/how_13191_prevent-seasickness.html