"I want him to eat as much fish as possible because that's his favourite... but I think radiation accumulates in creatures at the top of the food chain," she said.
Yokono, 27, now buys imported fish, but says she would support Japanese trawlermen if she knew what she was buying was safe.
The problem for Yokono is that she -- along with a significant proportion of the Japanese shopping public -- does not trust the government's safety standards.
In the immediate aftermath of the nuclear crisis, Tokyo announced it was raising the permitted level of radiation in food by a factor of five, meaning produce that would previously have been thrown out was suddenly alright.
Rice grown just a short distance from the plant was declared safe after spot sampling, but later tests revealed radiation levels far higher than even the new raised limits.
Hiroaki Koide, assistant professor at Kyoto University Research Reactor Institute, said the official declaration that food with five times the previous "safe" level of radiation was fit for consumption raised suspicions the government was acting on behalf of producers, instead of consumers.