Because the ocean is so huge
"Officials: No nuclear risk to North Pacific fish"(also here)
...a spokeswoman for the federal Food and Drug Administration tells the Anchorage Daily News that the ocean is so huge, and Alaska fisheries so far away, that there is no realistic threat. Alaska's food safety program manager, Ron Klein, says the FDA and the National Oceanic and Atmospheric Administration have demonstrated that Alaskans have no cause for worry. Klein says that based on the work they're doing, no sampling or monitoring of our fish is necessary
"...based on the work they're doing." What kind of work? Does it include sampling? They just said it wasn't necessary, so no. Blanket assurances from officials are always reassuring.
New York Times, "In Financial Crisis, No Prosecutions of Top Figures"
It is a question asked repeatedly across America: why, in the aftermath of a financial mess that generated hundreds of billions in losses, have no high-profile participants in the disaster been prosecuted? Answering such a question — the equivalent of determining why a dog did not bark — is anything but simple.