1. We are told that the bulk of the radiation in Japan is blowing out to sea.
2. The Pacific is full of life.
3. Japanese people eat lots of seafood.
4. Irradiated sea creatures turn into mutant monsters. We know this from the Godzilla historical documentaries.
5. Ingesting mutant flesh turns you into a zombie. (Everybody knows this.)
6. Therefore, Japanese people will not simply get higher rates of cancer from eating fish poisoned with cesium. Tokyo will become a battleground between Godzilla and an army of ninja zombies.
Okay, I'm just having some fun. But in all seriousness I don't think the idea that a possible seafood-path might expose Japanese citizens to nuclear fallout has been investigated. I've heard about the food-path for milk and iodine, but nothing about fish and cesium.