There seems to be a lot of unsubstantiated rumors flying around on the internet regarding the toxic radiation being spilled into the Japan Waters. Spilling large quantities of radiation into the ocean is definitely not good and a topic we should all be looking into thoughtfully, but from what I have seen, there is nothing of striking evidence that we need to be worried about going into the Pacific waters in the US or Hawaii or eating local fish.
One pretty image was getting passed around all over the internet with a NOAA logo on it with a description of radiation spread across the Pacific. It turns out this image was actually showing a wave height forecast from the Tsunami for the hours after the Tsunami hit. This just goes to show how easy it is to spread rumors and false information over the internet, and we need think carefully about everything that the social or "real" media is passing to us. Its definitely easy to get freaked out about something like this.
The one news, that is substantiated, is the Blue Fin Tuna caught off of California that migrated from Japan showed marked levels of radioactive isotopes - caesium-137 and caesium-134. However, even with the increase, the quantity of radiation doesn't seem to be a great health risk.
I wouldnt worry about going in the ocean in Hawaii, but I think I would pass on any fish that I knew was caught off Japan...